# Yamaha carb adjustment instructions?



## Dillusion

So I got this here 50hp 2-stroke yammy...I have both the owner's manual and the service manual. But neither tells you how to 'adjust' the carbs as the mercury manual does.

The service manual tells you how to remove the carbs and re-install them, and shows you an exploded parts diagram...I found the chart with the float height and etc...but for the life of me, I can't find where it says my idle adjustment screw and my carb needles should be adjusted...IE- '1.5 turns out from lightly seated. The Merc manual for my old outboard says this in plain English, Yamaha, not so much.

I have a carb kit coming this week for all three carbs as well as a new fuel pump, fuel filter, and fuel enrichment gaskets/diaphragm...*but when I put it back together, it doesn't tell me how to adjust that silver carb needle inside of each carb? or the pilot screw on the side of the carb under the cap?*


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## cutrunner

The cap is the epa not wanting you to adjust idle mixture.
And you shouldnt have too.
Just clean the carbs and put it back togther as it was and it should be good to go.


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## Dillusion

> The cap is the epa not wanting you to adjust idle mixture.
> And you shouldnt have too.
> Just clean the carbs and put it back togther as it was and it should be good to go.


Ok, so the silver needle should just be lightly seated? How many turns out for the idle screw?

PS- the motor is not starting right now if the emergency fuel enrichment is set to normal...so I'm replacing all this stuff. The carb bowls were dirty on the bottom so something is clogged up. With the emergency enrichment set to 'on' the motor turns on, but stalls out and misfires and runs like chit.


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## cutrunner

You dont need to adjust anything imo.
Your problem is it has 10 hours on it then it sat and I would bet money on at least one of your idle jets (tiny) are clogged causing the hard start.
Trust me


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## Dillusion

> You dont need to adjust anything imo.
> Your problem is it has 10 hours on it then it sat and I would bet money on at least one of your idle jets (tiny) are clogged causing the hard start.
> Trust me


I'm with you, I completely agree something is clogged- that's why I'm rebuilding the entire fuel system from the QD to the carbs....I'm just used to merc carbs, that's all.

I know there's a silver needle valve in there and didnt know if it needed to be seated all the way or not- I guess I just seat it lightly and leave it!


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## MariettaMike

I cleaned mine a while back and was told by a Yamaha mechanic who looked it up in a book he had to set the idle mixture needle valves at 1-1/2 turns from seated as a starting point and adjust from there. That worked and I didn't touch them. (I have a 90)

The only other adjustement was idle speed located on the throtlle linkage of one carb. I did lower my idle speed.

I just cleaned under the cap by squirting carb cleaner through the hole with an infant nasal aspirator and then air. I did the same with all the other parts and it worked out fine.


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## cutrunner

Your right it does have a needle, and seat like any other carb I just cant understand what you mean by you cant find it?
Sorry im not following you


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## Dillusion

> I cleaned mine a while back and was told by a Yamaha mechanic who looked it up in a book he had to set the idle mixture needle valves at 1-1/2 turns from seated as a starting point and adjust from there. That worked and I didn't touch them. (I have a 90)
> 
> The only other adjustement was idle speed located on the throtlle linkage of one carb. I did lower my idle speed.
> 
> I just cleaned under the cap by squirting carb cleaner through the hole with an infant nasal aspirator and then air. I did the same with all the other parts and it worked out fine.


Mine doesnt have that black rubber cap next to the main jet, I have a silver needle valve that screws down. Which of those was your idle mixture needle?

My silver needle vale has no spring to put tension on it if it's loosened....


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## cutrunner

You really are losing me matty.
I thought about it and im pretty sure ive never done a 50. I have done 60, 70, 90 40, 25blah blah. 
Anyways I checked the microfisch just to be sure and its almost exactly like the 90.
Fwiw I looked up a 2005..


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## Creek Runner

I'm just not going to say it, same thing we went through with setting the timing on his Merc. Everyone wants to be a boat Mechanic. Those carbs are simple, I can have them off, cleaned, back on and running in an hour. Take it to a shop!

Also didn't in the other post you tell me that the carbs were just rebuilt by a Yamaha dealer, as I told you the carbs would need to be gone through due to the lack of use. 

Also those pictures don't show the air/fuel mixture screw (not called idle mix screw) the air/fuel mixture screw is located on the outside of the carb just like every other 2 stroke outboard carb in the world!


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## AfterHours2

Not to confuse things anymore than they already are but which type of screw is located under the brass factory plug that has to be drilled out to expose? I know I had to remove mine on my Yamaha to get to it. Maybe this could be it. Just thinking out loud..


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## Creek Runner

> Not to confuse things anymore than they already are but which type of screw is located under the brass factory plug that has to be drilled out to expose? I know I had to remove mine on my Yamaha to get to it. Maybe this could be it. Just thinking out loud..


Ding, ding, ding and the winner gets!


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## cutrunner

> I'm just not going to say it, same thing we went through with setting the timing on his Merc. Everyone wants to be a boat Mechanic. Those carbs are simple, I can have them off, cleaned, back on and running in an hour. Take it to a shop!
> 
> Also didn't in the other post you tell me that the carbs were just rebuilt by a Yamaha dealer, as I told you the carbs would need to be gone through due to the lack of use.
> 
> Also those pictures don't show the air/fuel mixture screw (not called idle mix screw) the air/fuel mixture screw is located on the outside of the carb just like every other 2 stroke outboard carb in the world!


X2

Either take it to a shop or take it apart, leave the idle mixture screws on the outside alone, soak it in good carb cleaner (merc powertune) for a day or two, clean with brakeclean and blow thru every oriface with air, put it back together and go.
As long as no one messed with the tuning screws it should run darn near perfect, like the factory desired


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## Dillusion

> I'm just not going to say it, same thing we went through with setting the timing on his Merc. Everyone wants to be a boat Mechanic. Those carbs are simple, I can have them off, cleaned, back on and running in an hour. Take it to a shop!
> 
> Also didn't in the other post you tell me that the carbs were just rebuilt by a Yamaha dealer, as I told you the carbs would need to be gone through due to the lack of use.
> 
> Also those pictures don't show the air/fuel mixture screw (not called idle mix screw) the air/fuel mixture screw is located on the outside of the carb just like every other 2 stroke outboard carb in the world!


The air fuel mixture on these is blocked by a cap.

No, the outboard is not going to a mechanic.

No, the carbs were not serviced by a tech. When I got there the guy said he did it himself....awesome I know.


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## Dillusion

I just took apart the fuel enrichment housing and pump. One of the metal paddles inside was completely disconnected, the screw and nut came loose. It was also full of black and orange debris.


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## Creek Runner

> I'm just not going to say it, same thing we went through with setting the timing on his Merc. Everyone wants to be a boat Mechanic. Those carbs are simple, I can have them off, cleaned, back on and running in an hour. Take it to a shop!
> 
> Also didn't in the other post you tell me that the carbs were just rebuilt by a Yamaha dealer, as I told you the carbs would need to be gone through due to the lack of use.
> 
> Also those pictures don't show the air/fuel mixture screw (not called idle mix screw) the air/fuel mixture screw is located on the outside of the carb just like every other 2 stroke outboard carb in the world!
> 
> 
> 
> The air fuel mixture on these is blocked by a cap.
> 
> No, the outboard is not going to a mechanic.
> 
> No, the carbs were not serviced by a tech. When I got there the guy said he did it himself....awesome I know.
Click to expand...




> Yeah I can do it all, I'm switching from mercury to yamaha so I'm not familiar with all of these new brands of things lol
> 
> Which LU oil now?
> 
> Edit: I am just going to call my local yammy dealer and find out what LU oil and yamalube I need and get a bunch.
> 
> Edit2: The owner of the engine said he got the carbs rebuilt already by a shop and has a receipt to prove it


Just going by what you said. 

I don't care if you do it your self or take it to a shop all my motors run fine to each his own. I was just offering you advice on what you should do as you are not a trained marine tech. I mean really it's $175 to have a shop go through them and then there done right and no guessing, BTW if they are not right they will burn a piston up and you will need a rebuild.


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## el9surf

If you cave in Gordon at central florida marine knows that engine very well. Not cheap but they can fix it. They always serviced both of my yami's (f40 and 50 2strk) and did a great job.
Hopefully you are not reverse engineering someone elses project.


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## Creek Runner

> If you cave in Gordon at central florida marine knows that engine very well. Not cheap but they can fix it. They always serviced both of my yami's (f40 and 50 2strk) and did a great job.
> Hopefully you are not reverse engineering someone elses project.


Surf he has a simple carb issue that would take any Yamaha tech about an hour to fix, no reverse eng. going on just needs some who knows what they are doing. 

That motor is about as simple as it comes, Suck, Squeeze, bang that's about it.


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## Dillusion

> I'm just not going to say it, same thing we went through with setting the timing on his Merc. Everyone wants to be a boat Mechanic. Those carbs are simple, I can have them off, cleaned, back on and running in an hour. Take it to a shop!
> 
> Also didn't in the other post you tell me that the carbs were just rebuilt by a Yamaha dealer, as I told you the carbs would need to be gone through due to the lack of use.
> 
> Also those pictures don't show the air/fuel mixture screw (not called idle mix screw) the air/fuel mixture screw is located on the outside of the carb just like every other 2 stroke outboard carb in the world!
> 
> 
> 
> The air fuel mixture on these is blocked by a cap.
> 
> No, the outboard is not going to a mechanic.
> 
> No, the carbs were not serviced by a tech. When I got there the guy said he did it himself....awesome I know.
> 
> Click to expand...
> 
> 
> 
> 
> 
> Yeah I can do it all, I'm switching from mercury to yamaha so I'm not familiar with all of these new brands of things lol
> 
> Which LU oil now?
> 
> Edit: I am just going to call my local yammy dealer and find out what LU oil and yamalube I need and get a bunch.
> 
> Edit2: The owner of the engine said he got the carbs rebuilt already by a shop and has a receipt to prove it
> 
> Click to expand...
> 
> Just going by what you said.
> 
> I don't care if you do it your self or take it to a shop all my motors run fine to each his own. I was just offering you advice on what you should do as you are not a trained marine tech. I mean really it's $175 to have a shop go through them and then there done right and no guessing, BTW if they are not right they will burn a piston up and you will need a rebuild.
Click to expand...

I know what I typed previously, that was before I picked it up and asked the previous owner about it.


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## cutrunner

Blow


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## Dillusion

> Blow


Huh?

I know his engine is very easy to work on. I was asking a question to verify what I was already doing. This engine is a simple one just like the merc 25. Just more carbs lol

I don't see how you can blow a piston with a carb...unless you pinch an oil line somehow.

I will rebuild the carbs and pumps and that's it. Thanks to those who were helpful.


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## Creek Runner

> Blow
> 
> 
> 
> Huh?
> 
> I know his engine is very easy to work on. I was asking a question to verify what I was already doing. This engine is a simple one just like the merc 25. Just more carbs lol
> 
> I don't see how you can blow a piston with a carb...unless you pinch an oil line somehow.
> I will rebuild the carbs and pumps and that's it. Thanks to those who were helpful.
Click to expand...

And that sir is why you should take it to a shop, and if it's wrong you will find out how. 

I was just as helpful as anybody else on this post just like I was on every other post you have made about Mech. work.

My issue isn't that you try and do it yourself or that you ask questions it's that you don't listen, and that you try to come off as this great tech, well sir I'm sorry you're not, you probably could be but you don't have the experience or training. You post on other threads about what people should do to their engine to fix it, then post up your own questions on how to fix yours. That's my problem, with your post, I'm as helpful as it comes to people even offered to fix your 25 merc for free if you brought it to me. Heck I will even offer to fix this one for free if you drive her up to me, (Parts not Included). I have also helped other people on this forum.


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## cutrunner

I was just finishing creek runners last sentence. Suck squeeze bang blow

A motor can certainly lose a piston from a clogged carb.
A clogged carb is a lean condition.
Its why nitrous kills so many motors.
The gas itself isnt some kind of super combustible fuel.
All it does is bring the incoming airs temp down greatly, giving the motor more air (same as a turbo, just a different mousetrap). Whenever you put nitrous on a motor you have to put more fuel to it to make up for the increase in air or it will be lean. Google stoichiometric air fuel ratio.
But this is meant for a naturally aspirated engine (yours)

But yea a lean condition will put holes in the piston, break off a chunk of the ringland (excessive lean conditions)


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## Creek Runner

> Blow


Cut you may Blow I prefer to Bang, LOL! ;D


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## cutrunner

> Blow
> 
> 
> 
> Huh?
> 
> I know his engine is very easy to work on. I was asking a question to verify what I was already doing. This engine is a simple one just like the merc 25. Just more carbs lol
> 
> I don't see how you can blow a piston with a carb...unless you pinch an oil line somehow.
> I will rebuild the carbs and pumps and that's it. Thanks to those who were helpful.
> 
> Click to expand...
> 
> And that sir is why you should take it to a shop, and if it's wrong you will find out how.
> 
> I was just as helpful as anybody else on this post just like I was on every other post you have made about Mech. work.
> 
> My issue isn't that you try and do it yourself or that you ask questions it's that you don't listen, and that you try to come off as this great tech, well sir I'm sorry you're not, you probably could be but you don't have the experience or training. You post on other threads about what people should do to their engine to fix it, then post up your own questions on how to fix yours. That's my problem, with your post, I'm as helpful as it comes to people even offered to fix your 25 merc for free if you brought it to me. Heck I will even offer to fix this one for free if you drive her up to me, (Parts not Included). I have also helped other people on this forum.
Click to expand...

Let me add to this..

Matty, I as sell as creek have no problem with someone working on their own stuff. Either they are actually doing it right or they made it worse and I'll be fixing it later.
Were only trying to help, so please take our advice and use it.
I know you do computer programming or web design something like that. Believe me, if you told me how to fix something on my computer I would take your word for it, so do the same for us


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## Dillusion

I never said you who was not being helpful. Don't know why you took offense to that. If I blow my motor I own up to it and I get it fixed if and when it comes to that.

Again, thanks for the help and advice but if the issue is not fixed and the motor does not run properly after I do this carb clean and etc, then ill drive up to Jacksonville and take it to you. Deal?


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## MariettaMike

#11 for a 2002 90TLRA Carbuerator Outboard Motor

http://www.yamaha-motor.com/partviewer/default.aspx?ls=outboard#/Yamaha/90TLRA_-_2002/CARBURETOR/90TLRA_(2002_OUTBOARD_MOTORS)/CARBURETOR_(90TLRA_-_2002)


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## Dillusion

> #11 for a 2002 90TLRA Carbuerator Outboard Motor
> 
> http://www.yamaha-motor.com/partviewer/default.aspx?ls=outboard#/Yamaha/90TLRA_-_2002/CARBURETOR/90TLRA_(2002_OUTBOARD_MOTORS)/CARBURETOR_(90TLRA_-_2002)


#11 is not adjustable on my motor. It is blocked off with a brass cap.

What I was asking about was the silver pin needle that comes in the carb kit.

The silver needle valve in this photo:










EDIT:

*My carbs are missing the rubber cap inside the carb. The fuel enrichment pump gaskets were also installed incorrectly.*


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## Creek Runner

The silver screw/needle is the adjument screw for the fuel/air mixture. Just on your motor they are blocked off, remember the kits are for multiple engine models. 

Also you can remove the brass plug to gain access to the adjustment screw just 99.9% of the time you don't need to and shouldn't.


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## Creek Runner

> I'm just not going to say it, same thing we went through with setting the timing on his Merc. Everyone wants to be a boat Mechanic. Those carbs are simple, I can have them off, cleaned, back on and running in an hour. Take it to a shop!
> 
> Also didn't in the other post you tell me that the carbs were just rebuilt by a Yamaha dealer, as I told you the carbs would need to be gone through due to the lack of use.
> 
> Also those pictures don't show the air/fuel mixture screw (not called idle mix screw) the air/fuel mixture screw is located on the outside of the carb just like every other 2 stroke outboard carb in the world!
> 
> 
> 
> X2
> 
> Either take it to a shop or take it apart, leave the idle mixture screws on the outside alone, soak it in good carb cleaner (merc powertune) for a day or two, clean with brakeclean and blow thru every oriface with air, put it back together and go.
> As long as no one messed with the tuning screws it should run darn near perfect, like the factory desired
Click to expand...

Best part about this thread is Cut said use something mercury makes ;D. He secretly like mercs!!!

But yes power tune is the best carb cleaning product for the last 20+ years.


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## Dillusion

> The silver screw/needle is the adjument screw for the fuel/air mixture. Just on your motor they are blocked off, remember the kits are for multiple engine models.
> 
> Also you can remove the brass plug to gain access to the adjustment screw just 99.9% of the time you don't need to and shouldn't.


That silver screw/needle is INSIDE my carb....not blocked off and not accessible from the outside when the carb is reassembled.


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## cutrunner

Mercurys oils, greases and other products are bar none the best, and you need it with a merc so it doesnt blow up and corrode ;D


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## cutrunner

> The silver screw/needle is the adjument screw for the fuel/air mixture. Just on your motor they are blocked off, remember the kits are for multiple engine models.
> 
> Also you can remove the brass plug to gain access to the adjustment screw just 99.9% of the time you don't need to and shouldn't.
> 
> 
> 
> That silver screw/needle is INSIDE my carb....not blocked off and not accessible from the outside when the carb is reassembled.
Click to expand...

We need pics homie


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## Dillusion

Ask and ye shall receive:

current state of the union-
(even using powertune like you said :-*)










This is a photo of EVERY SINGLE part that is removable from the carb besides the linkage on the side, and the one large gasket thats missing:










Photo of carb with jets and needle removed:










This is EXACTLY where the jets and silver needle were installed before I got the motor in my hands (and the damn thing ran):










ALL THREE carbs are setup that way. And all three are missing the parts below:

As per this chart: http://www.boats.net/parts/search/Yamaha/Outboard/2004/50TLRC/CARBURETOR/parts.html

The carbs are missing in each one:
Part # 23, 24, and 28

In the diagram of the fuel enrichment pump from the middle carb, gaskets #42 were stacked up ontop of eachother and not spread out on both sides of the diaphragm screen like the microfiche says to do. Also part #38, one of the silver paddles was completely unscrewed and the hex nut was on the floor of the pump housing.


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## Creek Runner

Give me the serial number and model number to your engine so I can pull it up please because the done't look right to me. 

Cut does that look right to you. 

I don't think thats wear that silver needle goes your suppose to have a jet there. 

That silver needle goes in the top plate found on pic 1 of yours. 

I'm like 99.9% sure of that, heck I even have the same motor I can pull it apart and look at it. 

Also let me add that not all Yamaha motors had the fuel/air screw blocked off, in fact most didn't have them blocked off. It depended on where the motor was originally sold. By looking at your pics can't really tell but yours appear to open (not blocked off). Which is where the silver need screw goes.


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## Dillusion

There is a brass circle cap blocking where the needle screw would normally go. 

The model is 50TLRC and its a 2004.


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## Creek Runner

Take a picture of the brass cap your talking about please.


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## cutrunner

Creek
That doesnt look right at all...
The lowspeed jet goes in there.
I hope they didnt crossthread that needle screw into the jet hole.
This is what matty was trying to explain to us that made absolutely no sense.
I looked up the microfisch for a 2005 50 tlrd and it looks like it is supposed to, with the low speed jet


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## Dillusion

> Take a picture of the brass cap your talking about please.


Ok, I will stop by my house in an hour or so and take a pic. All it is a is a brass circle covering where that needle adjustment should be.


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## Dillusion

> Creek
> That doesnt look right at all...
> The lowspeed jet goes in there.
> I hope they didnt crossthread that needle screw into the jet hole.
> This is what matty was trying to explain to us that made absolutely no sense.
> I looked up the microfisch for a 2005 50 tlrd and it looks like it is supposed to, with the low speed jet


I'm not as retarded as you think, I'm fairly meticulous  

It's not cross threaded, that silver needle screw goes in very lightly without pressure


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## Dillusion

I placed an order for three of those jets, #24 for a 50hp that I posted from the boats.net diagram before. Should be here by the end of the week.


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## cutrunner

> Creek
> That doesnt look right at all...
> The lowspeed jet goes in there.
> I hope they didnt crossthread that needle screw into the jet hole.
> This is what matty was trying to explain to us that made absolutely no sense.
> I looked up the microfisch for a 2005 50 tlrd and it looks like it is supposed to, with the low speed jet
> 
> 
> 
> I'm not as retarded as you think, I'm fairly meticulous
> 
> It's not cross threaded, that silver needle screw goes in very lightly without pressure
Click to expand...

I never suspected you of being mentally ill, minus that picture of you poling with your shirt off ;D
The difference between a diy er and a real mechanic is I can tell you what your missing without the micfoische, and tell you what every little hole or channel in the carb is and what it does and why.


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## Dillusion

> Creek
> That doesnt look right at all...
> The lowspeed jet goes in there.
> I hope they didnt crossthread that needle screw into the jet hole.
> This is what matty was trying to explain to us that made absolutely no sense.
> I looked up the microfisch for a 2005 50 tlrd and it looks like it is supposed to, with the low speed jet
> 
> 
> 
> I'm not as retarded as you think, I'm fairly meticulous
> 
> It's not cross threaded, that silver needle screw goes in very lightly without pressure
> 
> Click to expand...
> 
> I never suspected you of being mentally ill, minus that picture of you poling with your shirt off ;D
> The difference between a diy er and a real mechanic is I can tell you what your missing without the micfoische, and tell you what every little hole or channel in the carb is and what it does and why.
Click to expand...

Noted 

I'm hoping that after putting the proper jets back in and a thorough cleaning, as well as new enrichment diaphragm parts and new fuel pump; that the motor will be running like a top. We shall see...

I don't think any damage came from the previous users carb mishaps here because the compression on all cyls is still 110 across all tree with a cheap gauge and all within 3-5% of each other


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## Creek Runner

> Creek
> That doesnt look right at all...
> The lowspeed jet goes in there.
> I hope they didnt crossthread that needle screw into the jet hole.
> This is what matty was trying to explain to us that made absolutely no sense.
> I looked up the microfisch for a 2005 50 tlrd and it looks like it is supposed to, with the low speed jet


Yeah I knew it wasn't right, that's why I posted earlier that the needle valve is not located inside, and is accessible from the outside. 

But Matty told me I was wrong, and that his was inside made go  [smiley=1-mmm.gif] then when he posted the picture I was like whoa that's not right. No wonder that darn thing wouldn't run. Guess good thing I was kind of sarcatic earlier or we may not have gotten this far and been able to find out the issue, and he would have put them back together with the needle valve in the wrong location, just to have to take it back apart and start over.

What up with you 2 using Microfisch, I haven't used Microfisch since like 1995 I use yamaha yes/smart program on my laptop.


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## Creek Runner

> Creek
> That doesnt look right at all...
> The lowspeed jet goes in there.
> I hope they didnt crossthread that needle screw into the jet hole.
> This is what matty was trying to explain to us that made absolutely no sense.
> I looked up the microfisch for a 2005 50 tlrd and it looks like it is supposed to, with the low speed jet
> 
> 
> 
> I'm not as retarded as you think, I'm fairly meticulous
> 
> It's not cross threaded, that silver needle screw goes in very lightly without pressure
> 
> Click to expand...
> 
> I never suspected you of being mentally ill, minus that picture of you poling with your shirt off ;D
> The difference between a diy er and a real mechanic is I can tell you what your missing without the micfoische, and tell you what every little hole or channel in the carb is and what it does and why.
> 
> Click to expand...
> 
> Noted
> 
> I'm hoping that after putting the proper jets back in and a thorough cleaning, as well as new enrichment diaphragm parts and new fuel pump; that the motor will be running like a top. We shall see...
> 
> I don't think any damage came from the previous users carb mishaps here because the compression on all cyls is still 110 across all tree with a cheap gauge and all within 3-5% of each other
Click to expand...


Oh he is mentally ill, lol! J/K matty that motor will run just fine, no way he ran it like that for any length to damage anything cause it wouldn't operate properly the way it was.

I still want more pics, of all angles, and of the top plate, all angles. I think I see something, but want to be sure before I post.


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## cutrunner

I just call it microfisch...
Dont know why
Maybe ill quit calling it something that it isnt


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## Creek Runner

> I just call it microfisch...
> Dont know why
> Maybe ill quit calling it something that it isnt


Oh okay, for a min there I thought you were old school, lol! I use to play with the microfisch as a kid in my dad's dealer until I would get caught and yelled at and made to go clean parts.


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## cutrunner

Too young to be oldschool...


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## Dillusion

This is what that brass cap looks like, to entertain the previous request:


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## devrep

I just did complete disassembly and cleaning on the 3 carbs on my 2005 50tlr 2 stroke. I drilled out the brass caps with a small bit, threaded in small screws a couple turns and pulled the caps with a pair of pliers. the air screws were almost completely closed, maybe 1/20th of a turn out. I turned them all 1 1/4 turns out. I warmed the engine up and adjusted the screws some to get a smooth idle. it seems 1 1/4 turns out was right on the money (I had read it on another forum written by a Yamaha tech). my engine has never idled so smooth or idled down so slow in gear. It has never run this well. I did seem to lose about 1/2 mph on my gps for some reason.


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## Dillusion

> I just did complete disassembly and cleaning on the 3 carbs on my 2005 50tlr 2 stroke.  I drilled out the brass caps with a small bit, threaded in small screws a couple turns and pulled the caps with a pair of pliers.  the air screws were almost completely closed, maybe 1/20th of a turn out.  I turned them all 1 1/4 turns out.  I warmed the engine up and adjusted the screws some to get a smooth idle.  it seems 1 1/4 turns out was right on the money (I had read it on another forum written by a Yamaha tech).  my engine has never idled so smooth or idled down so slow in gear.   It has never run this well.  I did seem to lose about 1/2 mph on my gps for some reason.


I might drill them out tonight, even if I don't touch the needle inside.


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## MariettaMike

Those are very thin. You can poke an ice pick or point of a cork screw threw the middle and pry them out easily. Throw them away.


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## Dillusion

I took the brass caps off, if for no more reason than to clean that needle jet thoroughly with all the debris i've been finding in the fuel system...

The caps came off easily.

The top carb was 2 turns out, and the bottom two carbs were both 1.5 turns out. When I re-install them I will do all three to 1.25 turns out. Seems to me 2 turns is running very lean?

Besides the fact I had a god damn air/fuel mixture needle inside the damn carb lol...


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## DuckNut

Matty- on my motorcycle carbs they needed to be hooked up to a vacuum system to ensure all of the carbs are allowing the same exact amount of air through. Turning the screw 1.5, 2, or whatever might not be right.

I am quite handy with the tool box but I know my limitations - I have learned the hard way, I will not even touch a carb anymore (even a weedeater)- leave it to the pro's.


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## Creek Runner

No vacuum machine needed, they are staggered for a reason, but heck what do those factory engineers know. lol! 

You say it seems pretty lean and haven't even ran the motor yet? Geese dude I'm mean come on!


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## Dillusion

> No vacuum machine needed, they are staggered for a reason, but heck what do those factory engineers know. lol!
> 
> You say it seems pretty lean and haven't even ran the motor yet? Geese dude I'm mean come on!


I have ran the motor. It was running with these messed up carbs...

I'm saying two turns out is lean based on my mercury experience. Is there a problem with that?


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## Creek Runner

> No vacuum machine needed, they are staggered for a reason, but heck what do those factory engineers know. lol!
> 
> You say it seems pretty lean and haven't even ran the motor yet? Geese dude I'm mean come on!
> 
> 
> 
> I have ran the motor. It was running with these messed up carbs...
> 
> I'm saying two turns out is lean based on my mercury experience. Is there a problem with that?
Click to expand...

No way that motor ran right with the carbs the way you showed them in the picture, it may have started but it didn't run. So whatever conclusion you came to while the carbs were jacked up is irrelevant to whether or not its lean/rich. I can guarantee you that all 3 cylinders were lean the darn idle jet missing and was completely blocked by a screw in it didn't belong. 

The brass plugs were in still from the factory, so that means it has never been messed with what make you think the factory didn't know what they were doing. 

Lots of motors have staggered settings even on mercs, the older 4s merc every carb was set at a different setting. 

Matty even though I bust your chops pretty good, doesn't mean I have anything against you or wouldn't help you any way I could. Just thought I need to add that!


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## Dillusion

I swear to god the motor ran...I wouldn't have bought it if it didnt. I dont know how...but it ran on the hose for 10 minutes and I checked compression before and after...I dont know what to say lol


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## AfterHours2

I was burned once by the running great on the hose routine. The only way that I would purchase a used motor is putting it under a load. Pretty hard to do in your instance but it will always save you a ton of headache and help diagnosis.


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## Dillusion

> I was burned once by the running great on the hose routine. The only way that I would purchase a used motor is putting it under a load. Pretty hard to do in your instance but it will always save you a ton of headache and help diagnosis.


It was off the boat, nothing I could do.

After seeing the shenanigans in the carb, I'm going to redo the water pump too.

New spark plugs came in today as well as new fuel pump. Waiting on replacement idle jets, carb kit, diaphragm kit, and fuel filter.


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## cutrunner

> No vacuum machine needed, they are staggered for a reason, but heck what do those factory engineers know. lol!
> 
> You say it seems pretty lean and haven't even ran the motor yet? Geese dude I'm mean come on!
> 
> 
> 
> I have ran the motor. It was running with these messed up carbs...
> 
> I'm saying two turns out is lean based on my mercury experience. Is there a problem with that?
> 
> Click to expand...
> 
> No way that motor ran right with the carbs the way you showed them in the picture, it may have started but it didn't run. So whatever conclusion you came to while the carbs were jacked up is irrelevant to whether or not its lean/rich. I can guarantee you that all 3 cylinders were lean the darn idle jet missing and was completely blocked by a screw in it didn't belong.
> 
> The brass plugs were in still from the factory, so that means it has never been messed with what make you think the factory didn't know what they were doing.
> 
> Lots of motors have staggered settings even on mercs, the older 4s merc every carb was set at a different setting.
> 
> Matty even though I bust your chops pretty good, doesn't mean I have anything against you or wouldn't help you any way I could. Just thought I need to add that!
Click to expand...

There is one way it will run....
I saw this once, get ready to laugh...

So I have a guy come in say hes got a yamaha f40 thats not running right (imagine that..)
Anyways so carbs are my first thought.
I pull em off the motor and take em apart. Like I thought they were all at least partially clogged.
But it ran pretty good, sputtered a tiny bit and was hard to start, and almost got full rpm.
So I keep in mind something weird is going on because it shouldnt run that good..
Im looking at the intake as im putting it back together and someone black duct taped over half of the air Intake screens, essentially running it half choked.
I learned that day that if your carbs are all partially clogged and you half choke a motor it will run a whole lot better than ya think..


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## devrep

does anyone know why they put the rubber caps over the pilot jets? when I took my carbs apart one of them was out and laying in the float bowl. I've been racing and riding 2 stroke MX bikes most of my life and I've never seen a pilot jet with a rubber plug in it. not sure how it can even work that way.


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## cutrunner

What motor what year?


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## Dillusion

> What motor what year?


The microfiche for my motor shows the black plug. Part #23 on the carb diagram. 2004 50tlrc


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## Creek Runner

> does anyone know why they put the rubber caps over the pilot jets?  when I took my carbs apart one of them was out and laying in the float bowl.  I've been racing and riding 2 stroke MX bikes most of my life and I've never seen a pilot jet with a rubber plug in it.  not sure how it can even work that way.


It blocks of the fuel bowl from the idle jet so all fuel flows through the pilot jet, there is a passage that fuel flows between the idle and pilot jet. No fuel entering the idle jet comes from the bowl directly, it creats a more precise metered flow.


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## devrep

thanks!


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## cutrunner

Any uodates?


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## Dillusion

> Any uodates?


Boats.net had to order everything. Nothing was in stock, naturally. The three jets and carb kit as well as enrichment pump gaskets should be here late next week.

I did the water pump, thermostat, fuel filter, and fuel pump today.

I am memorizing how to sync and link and check the oil pump as we speak. I emptied all the oil out of the tank and with the key in the on position the alarm goes off, so it's good to know that works and isn't gunked up.

The auto fuel enrichment needle assembly tested working ok at 3.1 ohms, so that's good to go as well.

One thing I found after disassembling the carbs, is when they were reassembled, the oil line leading to the middle carb was pinched and not seated correctly. Another awesome little surprise. Luckily the compression is still good.


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## cutrunner

The "mechanic" that did that carb job needs to stop "practicing"...


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## Dillusion

> The "mechanic" that did that carb job needs to stop "practicing"...


He has an account here, I think he did it all with good intention...it just came out all wrong. 

Once I'm done with it the motor will be back to new....or st least that's the plan.


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## Dillusion

Carb kit came yesterday. Expecting the jets today along with the diaphragm kit for the enrichment pump...may come tommorow, though.


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## Dillusion

Got my boats.net order,they only sent two of the three jets. I hate them now.


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## TwoKids

Matty,
FWIW, I buy all my Yami parts from Andy Jr at SIM Yamaha simyamaha.com, SIM's prices are great and he has provided any tech info when I needed it. One time he didnt have an answer and he called Yamaha Corporate on my behalf. Great folks to deal with, family run business.


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## AfterHours2

Boat tune is just right down the road from ya. Sarah can get most parts unless they are in stock in 2 days or less. Little more pricey, but for smaller items I would rather pay an extra few bucks to leave with in hand. Food for thought in case you get in a jam and need a quick part...


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## Dillusion

> Boat tune is just right down the road from ya. Sarah can get most parts unless they are in stock in 2 days or less. Little more pricey, but for smaller items I would rather pay an extra few bucks to leave with in hand. Food for thought in case you get in a jam and need a quick part...


I got the carb kit from boat tune, because they are right by me. Heir prices are higher and I asked about all the extra gaskets and jets I needed but they were about 3-5$ more on each part and had nothing in stock. I saw their showroom and will definitely purchase stuff there in the future.

I called every yamaha place in central Florida and no one had it in stock....so I alled boats.net back and they said it should be at my door by next Wednesday.


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## Dillusion

Welp, everything is here...except...ONE JET. ONE JET! ONE FREAKING JET!!!!!!!!!!!!!!!! AKS#OHER)*#!HQLJDHOP!*H)[email protected]:L!JDH*!OHD

I AM SO FRUSTRATED RIGHT NOW.

Everything is reassembled except for one carb which is missing that one jet...MOTHER F!


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## Dillusion

Jet should be here tommorow.

Shenanigans to ensue after I get it.


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## Dillusion

Nevermind, the idiots at boats.net have no idea what in the blue hell they're doing.

No idea when the jet will be here.


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## Dadvocate

Last time I ordered from them most of the parts were BO. Prices were worth waiting for. Hang in there they will come. :'(


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## Dillusion

I had the part overnighted by a small shop in VA...IT WORKS! It runs now with the emergency enrichment switch in the 'normal' position.

Motor starts first crank. Runs great. Idles fine. OBVIOUSLY I havent put it under load yet or in a tank for that matter, but right now it's miles better than it was before.

My fuel filter housing is leaking, but that's an easy fix.

My question now is, how hot should this motor be running?

The water coming out of the pee tube is hot, and the top cylinder of the block is HOT to the touch. Much hotter than my 25hp merc 2s was...I can barely touch it...maybe for 3-5 seconds but that's it.

Does this motor have a temperature sensor alarm? I know there is a thermo switch with an orange wire connected by the sparks in the rear, but I dont know what it does exactly.

Normal?

*I figured it out. I was running on the hose. When I ran the outboard in a large tub I have, the pisser was even stronger and the block cooled down to where I could keep my hand on it for a long time.*


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## Dillusion

Here's a video of the outboard running in the tub

Embed fail. trying to fix it...

Nevermind !


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## Dillusion

[media]http://www.youtube.com/watch?v=AQ1US5J6hYw[/media]


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## Micholetti

You guys rock!  [smiley=thumbsupsmileyanim.gif]
My local shop wanted *$750* (ouch) to clean/rebuild my Yamaha 2001 50hp TLRZ carbs/enrichment system. I read this thread, watched a couple Utube videos about motorcycle carb rebuilds & got started this morning with a can of Quick Tune, a can of compressed air, & a bowl of mineral spirits. A very easy repair with great results both in the tub & on the water this evening.

It was interesting to find my motor didn't come with an under cowl fuel filter, thus all the debris found in the bowls & jets. Added a clear glass fuel filter before the squeeze bulb.


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## Dillusion

> You guys rock!  [smiley=thumbsupsmileyanim.gif]
> My local shop wanted *$750* (ouch) to clean/rebuild my Yamaha 2001 50hp TLRZ carbs/enrichment system. I read this thread, watched a couple Utube videos about motorcycle carb rebuilds & got started this morning with a can of Quick Tune, a can of compressed air, & a bowl of mineral spirits. A very easy repair with great results both in the tub & on the water this evening.
> 
> It was interesting to find my motor didn't come with an under cowl fuel filter, thus all the debris found in the bowls & jets. Added a clear glass fuel filter before the squeeze bulb.


Glad it helped!


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