1972 125 Johnson Erving on its own

[lwhiteb]

I cleaned the carbs put new gas in it.it has 120 compression on all cylinders.when I started it it was running ok then revved up to 3500 rpm and ran like that for several minutes then idled down.then it revved up again.when it's running it sputters thru the bottom carb and a puff of smoke will come out at the prop at the same time.what could cause this

 

[boobie]

Re: 1972 125 Johnson Erving on its own

Do a sync and link on it and make sure you don't have any linkage hanging up after doing the carb job.

 

[emdsapmgr]

Re: 1972 125 Johnson Erving on its own

Agree. It's possible that the butterflys on one carb are not closing completely at idle.

 

[lwhiteb]

Re: 1972 125 Johnson Erving on its own

Ok guys i adjusted the carbs so that they are closed at idle.it still revs up to 3000 rpm and revs up and down.and the plugs are wet with gas now.when it shuts off fuel comes out the front side of the carbs.i have pulled the carbs twice and the floats are adjusted correctly.does anyone know why it's doing this

 

[emdsapmgr]

Re: 1972 125 Johnson Erving on its own

Have you checked the degrees of timing at idle? A broken reed will be evidenced when fuel spits back out of the carb each rpm of the engine.

 

[steelespike]

Re: 1972 125 Johnson Erving on its own

Sounds to me like a fuel delivery problem Motor could be running ok occasionally starving as it leans out it revs up as 2 strokes are inclined to do,then the fuel catches up perhaps because the pump works better at higher rpm.
Probably pretty far fetched.
You could try squeezing the primer bulb or maybe a little choke.
Fuel coming out the carbs would indicate the floats or float valves aren't closing.