# choke on a merc 2 stroke?



## Un-shore (Sep 27, 2007)

I went to look at an '85 merc 9.9 2 stroke last night. The motor started with the choke knob pulled out all the way but stalled when I pushed it back in. If you only push it back in only about 3/4 of the way it stays running. When I did that it wasn't like there was a point that it clicked into that spot so I had to just kind of delicately push it in to that point and be careful not to pass it. Even after letting the motor run for a while it still stalled when I pushed the knob in. Is this normal? The knob says idle fast slow on it and turns. Is there a trick to this?


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## B.Lee (Apr 29, 2008)

Just an educated guess, but it sounds like the pilot jet may be clogged. it supplies fuel at idle and very low rpm. it also tends to clog first when old gas varnishes up a dirty carb. 

The engine will run on choke and half choke, as the choke will either induce more vacuum to pull more fuel in, or in some cases the choke is a primer circuit, and feeds fuel itself. 

Should be a simple carb clean to get it running good, provided there are no other issues, like low compression, weak spark, etc.


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## hoser3 (Mar 24, 2008)

I would have a compression test done and if that checks out I would say just clean and rebuild the carb. How it is acting now is a standard indication that the carb needs to be cleaned. Good luck


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## Guest (Jul 18, 2008)

Not normal for a Merc but I'm used to the later models. Sounds like a carb job to me. Merc seem to be a little cold natured but from my experience, but not as bad as Yami. Did you let it warm up pretty good before pushing in the choke?

I do a compression check when I buy a used motor.


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## noeettica (Sep 23, 2007)

See if you can Borrow a Known good carb Beacuse If you are looking at Crankshaft seals that is A Pretty good chunk of change ...Also check for Good Spark ...(On my old Merc the Ignition system Costs MORE than the motor is worth ...)

Also look for any other vacuum leaks ... I bought a motor one time Dirt cheap I Inspected it saw a rotted hose closed the cowl ...Paid the Money .... loaded up the motor up , stopped by Napa bought the hose ... Later that Day Had the motor screaming its ASS off ...Whille Laughing My ASS off .... Previous owner said "what was it ?" I told him For $50 bucks I'll tell you ... He was a wise ass and thought he was putting one over on me ...LOL ... Sometimes we get Lucky .... Good Luck


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## Un-shore (Sep 27, 2007)

> Not normal for a Merc but I'm used to the later models.  Sounds like a carb job to me.  Merc seem to be a little cold natured but from my experience, but not as bad as Yami. Did you let it warm up pretty good before pushing in the choke?
> 
> I do a compression check when I buy a used motor.


I let it run for a good 5 mins. Comp. check is next, wanted to get the skinny on the choke thing first. The motor is almost brand new. the sellers dad won it in a raffle in '85 and never used it. The seller used it once (or so he says) and was not enough power. motor sat for 2-3 years with old gas in it. not a scratch on it, not even the skeg. cowling got scratched up in the guys garage from stuff getting piled on it.

I have no idea how I ended up here in the bragging spot, not looking where I'm webbing I guess.


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## deerfly (Mar 10, 2007)

> I have no idea how I ended up here in the bragging spot, not looking where I'm webbing I guess.


looks like you have some leeway to brag on mastering a sticky tricky choke on a 23 year old engine.


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## HaMm3r (Dec 11, 2006)

I have the same setup on my merc 8. Turning the knob to the right increases your idle speed, left lowers it. Out is full choke, in is choke off, but you probably figured all that out already. When starting mine cold, I use full choke and maybe 1/2 idle adjustment. After 30 seconds, choke off and then lower idle after 1-2 minutes.

I recently had a situation where the motor started running rough, then the next time I used it it was doing exactly what you described. I replaced all the fuel/oil in the tank with fresh, then added sea foam fuel treatment. What a difference! It's like a new motor now.  Still, I expect it's time for new plugs and a carb cleaning, so I'll be doing that here soon. Good luck...


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## Guest (Jul 18, 2008)

> > I have no idea how I ended up here in the bragging spot, not looking where I'm webbing I guess.
> 
> 
> looks like you have some leeway to brag on mastering a sticky tricky choke on a 23 year old engine.


 ;D ;D ;D ;D


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## cal1320 (Jun 6, 2007)

choke on a merc 2 stroke?
Chew it in smaller pieces


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## Un-shore (Sep 27, 2007)

> I have the same setup on my merc 8. Turning the knob to the right increases your idle speed, left lowers it. Out is full choke, in is choke off, but you probably figured all that out already. When starting mine cold, I use full choke and maybe 1/2 idle adjustment. After 30 seconds, choke off and then lower idle after 1-2 minutes.
> 
> I recently had a situation where the motor started running rough, then the next time I used it it was doing exactly what you described. I replaced all the fuel/oil in the tank with fresh, then added sea foam fuel treatment. What a difference! It's like a new motor now.   Still, I expect it's time for new plugs and a carb cleaning, so I'll be doing that here soon. Good luck...


I was only guessing that in all the way was idle, now I know. I hooked up a tank of fresh gas and changed the filter, he was using old gas and aircooled 2 cycle oil  to start it when I got there. so hopfully with a night of clean gas in the carb and what I know now I can get this thing running. Thanks everybody, I'll let you know what happens.


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## Un-shore (Sep 27, 2007)

> > I have no idea how I ended up here in the bragging spot, not looking where I'm webbing I guess.
> 
> 
> looks like you have some leeway to brag on mastering a sticky tricky choke on a 23 year old engine.


Just got lucky, I break more things than I fix messing with things I shouldn't!


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## stickwaver (May 13, 2008)

> choke on a merc 2 stroke?
> Chew it in smaller pieces


LOL- what the hell does that mean?!


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## mad_redfisher (Jul 22, 2008)

yea turn the nob to the right and see watt it dus i had the same problam with mine


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## noeettica (Sep 23, 2007)

I have a low time 15 merc was doing the same thing ...took it out on lake tarpon and after 30 minutes it cleared right up  

These carbs are Weird ! They have no real choke , just a primer and enrichment valve ... still learning ...going to dig out my spare carb and play with it a while and see what I can learn ...

Dave


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## TomFL (Oct 2, 2007)

One word: Chemtool. Get a can of it at Wally-World in the automotive section, put some in the tank and let it run. It'll clear up in less than 5 minutes, guaranteed. 

http://www.berrymanproducts.com/Default.aspx?tabid=140 it's the second can down the list, B-12 chemtool

Trust me, the stuff has saved my bacon so many times it's not even funny anymore. 

-T


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## Flyline (Mar 3, 2008)

if your motor runs like syht then I highly adjusted you to use a carb and power tuner spray can (quicksilver spray can) then take the spark plugs off and then spray into the piston area. pull the cord until another piston gets close the the spark valve area then spray it again then let it sit for a day and do it same thing one time a day for 3 days.

your carburator and your piston will runs like brand new again! runs like u stole the motor on the water.

that's what I did to 2003 yamaha 9.9 2-stroke after been sitting new in box for 5 years! my 9.9 2-stroker runs like never broken in yet with double oil then after 11 hours later with 100:1 ratio/BP gas station then my motor runs unbelivable!!!!!! now it ready to tune up for upgraded to 15hp by changing the reed assembly and some ther stuff!

good luck! I'm drinking Crown and Coke!


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## noeettica (Sep 23, 2007)

What kind of Oil ???


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