# 2003 70hp Yamaha - Poppit???



## Dillusion (May 21, 2012)

You mean the thermostat? It's there on the top-side-corner of the engine by the oil tank.


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## gtpvette (Jun 4, 2013)

> You mean the thermostat? It's there on the top-side-corner of the engine by the oil tank.


No not the thermostat. On the larger Yamaha motors there is the poppit valve. The way I understand it,,, it allows pressure in the cooling system to bleed off if it's too high. Of course it needs to close fully to allow the cooling sytem to work. It seems to be changed when the thermostat is. 

BTW,,, read your Carb cleaning thread. I need to do that as well. Gas tank is full of water and other crap. Carbs need to be cleaned.


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## Dillusion (May 21, 2012)

Here is the crankcase parts diagram for your motor:

http://www.boats.net/parts/search/Yamaha/Outboard/2003/70TLRB/CYLINDER%20CRANKCASE/parts.html

The only thing I see on there, is the thermostat assembly.

There's guys who will chime in that know more than me though...I could be wrong.


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## Creek Runner (Sep 1, 2011)

> > You mean the thermostat? It's there on the top-side-corner of the engine by the oil tank.
> 
> 
> No not the thermostat. On the larger Yamaha motors there is the poppit valve. The way I understand it,,, it allows pressure in the cooling system to bleed off if it's too high. Of course it needs to close fully to allow the cooling sytem to work. It seems to be changed when the thermostat is.
> ...


Your engine does not have a popit valve just the thermo on the exhaust housing. Only the larger ones with the thremo on the head had popit vavles.


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## gtpvette (Jun 4, 2013)

Thank you gents!


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## gtpvette (Jun 4, 2013)

Got the carbs off this weekend,,, and pumped out the old gas. What a mess. Here's what the first of the gas looked like:











Don't know if it's just water or 'phase seperation',,, but I pumped out everything I could which was almost 15 gallons on a 30 gallon tank. towards the end the fuel looked pretty good though. The lingering question is,,, is the pickup all the way on the back of the tank?? Do they normally put the pickup iat the back of the tank??  If not I doubt I got everything out. I did pick up a RACOR so that should help. 

Good thing I had a fuel pump at the house,,, it would of taken forever squeezing that ball:










OK,,, so the carbs. This was the top carb. It's toast as I was unable to get the main jet out. It's fused in there. I tried heat,,, then drilling it out then hitting it with an Easy-out,,,, it broke off. Ordered a new one from SIMS. When you consider the rebuild kit is $40 and the new carb is $145 it's not a bad deal. 










Let me ask another question. The middle carb has a cold start attachment,, I think they call it fuel enrichment. The part #33 in the diagram below is the trigger. The way I read it is when the motor has been off and cold, the plunger is retracted in the housing which activates the fuel enrichment,, once the motor has been on for a while,,, the plunger extends turning it off. The manual says to verify it's working,,, turn the key on for a while and it shoud extend. Mine not's doing anything. It appears to me that it's all the way extended already and the bottom of the plunger is flush  with the mounting flange. Does that sound wrong?? I'm thinking the plunger should be up inside the housing some,,, but I'm not sure. Any thoughts??


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## Dillusion (May 21, 2012)

WOW that carb is bad. I have never seen a carb like that before.

As for the fuel enrichment pump. I rebuilt and checked mine.

Do you have a multimeter with an ohms setting? With the fuel enrichment pump disconnected (mounted or not) from the wiring harness: 

Fuel enrichment valve resistance:
Blue - Black
2.32 ~ 3.48 [ch937] at 20°C (68°F)

I coped and pasted that from the yamaha manual...I tested mine like this and mine read about ~3.1ohms so it was good to go.

Even when it's removed from the carb, the fuel enrichment pump needle does NOT retract all the way into the housing. I THINK, i read somewhere, that there is a wax ball inside the housing and it melts when the motor is warmed up which moves the needle.

The motor should be able to start and run without the need to move the red switch at all, and it should be in the 'normal' position at all times. If the motor needs the red switch in 'open' to run, then you have a clog somewhere in the enrichment pump diaphragm or fuel pump.


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## gtpvette (Jun 4, 2013)

> WOW that carb is bad. I have never seen a carb like that before.
> 
> As for the fuel enrichment pump. I rebuilt and checked mine.
> 
> ...



Yep,,, those are some carbs aren't they??? This boats been sitting a while. Surprisingly the other two cleaned up pretty well. Only had 1 bowl screw that gave me a problem. It's been a lot of years since I did dirt bikes carbs! 

Saw the test you mentioned in the manual,,, don't have a multi meter yet,,, the plan was to get one this week though. I didn't test the leads to see if 12v was applied when the key was turned on either. Just ran out of time.

It just seems that the plunger and needle are already extended. I would love to see a new part to see how extended/retracted it is.


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## Dillusion (May 21, 2012)

Here's one:


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## gtpvette (Jun 4, 2013)

> Here's one:



Yep,,,, that's the way mine looks. The bottom of the plunger is about flush with the flange. Was that yours????


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## Dillusion (May 21, 2012)

No that's not mine, I dont remember mine having that silver cylinder though. It might have.


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## gtpvette (Jun 4, 2013)

Got a reply on the Yamaha forum. They said that it get power from the charging system,,, not the key. I'll splice in a 12v source this weekend and see what happens.


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## cutrunner (Jun 8, 2010)

Dont cut any wires.
The enrichment needle should have bullet connectors on the wires

Wow those csrbs looked really bad btw.
Make extra sure to puge the fuel system with fresh fuel before you prime up the clean carbs


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## Creek Runner (Sep 1, 2011)

Thats correct the power comes from the stator, as cut said don't cut any wires. No need for a direct 12v source as you will melt it. 

Matty is spot on the enrichment systems uses a wax ball that when power is supplied to it melts which retracts the needle then when power is stop the opposite occurs. 

The pic that Matty posted is correct in the way it should look. 

Carbs are pretty nasty but trust me I see ones like that every spring! Next time soak the carbs over night in power tune and the main jet will come right out. 

Good luck standing by


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## gtpvette (Jun 4, 2013)

Thanks guys,,, took last weekend off and went fishing offshore so no work was done. My new carb should be here tomorrow,, so I'm hoping to get her started on Saturday. I've gotten a new 6 gal tank to run it off of for now so I can flush the main tank a bit more. I think I'll do premix first and verify the oil pump is functional while I'm at it. May try a tub of vinegar to flush the motor in while I'm at it. 

As a side note. The gauges in the console are pretty much toast so I'm looking at a new setup. I'm thinking all I really need is a Yamah multifunction tach and fuel. it currently has a speedometer, tach, water presure, tilt/trim and fuel. 

I've been looking for wiring diagrams for the 10 pin harness and the stand alone key switch. Anybody have one to share??


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## gtpvette (Jun 4, 2013)

Good news. I got a new engine harness, remote control, tach and key switch and hooked them up. The engine started right up. Amazing, Yamaha is really plug and play. Tach all seems to work less the trim indicator. I need to replace the sensor on the motor. 

I also stripped everything that was left out and removed the center console. I brought it back to the house to fiberglass up the no longer needed holes, cut some new ones and a repaint.  








  

Ordered a new teleflex steering kit, FF/GPS, compass and fuel gauge, switch panel, batery switch etc etc. Funny how these project expand with the 'well,,, since I'm doing x I might as well do y'.


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## gtpvette (Jun 4, 2013)

So this past weekend I decided to flush (or douche as my neighbor called it  ;D) my motor with vinegar. As I needed to replace the waterpump and the foot was off... I thought I'd take that opportunity. I decided to use a Harbor Freight fountain pump to circulate white vinegar through the motor.  

OK here's the pump I bought,,, $18 bucks 260 gallons an hour. Pump had lots of different attachments for different hose sizes. One was the same size as the tube that connected to the water pump and feeding water to the the motor. If I were to do it again,,, I'd get a bigger pump. 










I got some clear plastic tube and one hose clamp to attach the fountain pump to the water lift tube and a 5 gallon bucket filled with 3 gallons of white vinegar. Plug it in and go.










At this point I had vinegar going everywhere. I rerouted the pee hose,, then just clamped it off,,, then wraped a plastic bag around everything. Worked like a champ,,, let it run for 4 hours,,, figured about 1000 gallons went through the motor. 











Let me also mention this. When removing the thermostat,, one of the bolts sheared off. So to get this rolling I improvised. Worked fine for the flush. Still need to figure out how I want to fix this.  










So the results. I don't have lots to go on but the port inside the thermostat had all kinds of crap in there as well as the copper water lift tube that I connected the fountain pump to. After 4 hours,,, both were as clean as a whisle. I'm a believer


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## Dillusion (May 21, 2012)

Broken bolts in outboard block suck huge balls.

Your going to need to try using a reverse drill bit or an extractor bit to remove it. If that doesn't work you need to drill out the old screw and use a helicoil to retap it or manually retap it to a bigger size.

You can also try welding on a nut in order to extract it gain with a wrench depending on the situation and where it's broken off


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## gtpvette (Jun 4, 2013)

I drilled a hole in it last weekend and tried an EZ-Out. After breaking one trying to get the main jet out of the carb I really didn't want to put too much presure on it so it didn't do much. I went ahead and drilled most of it out. I'm a little off center but I think I'll be OK. I'll bring my tap set this weekend so we'll see if I can get this squared away.


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