Vacuum Leak

BigNiner19

Petty Officer 1st Class
Joined
Jul 1, 2006
Messages
234
Got a late 80's/early 90's Johnson 60HP. Motor seems to run pretty good at cruise and WOT. Even fast idle seems not so bad. However, the motor does not like to idle slowly and really doesnt like to go in and out of gear/nuetral/reverse. I have been messing with the timing some, and it has gotten a little better.

However, Im really beginning to think I have a vacuum leak somewhere. This could create a big problem on a 2 stroke I would think. Any where in particular I should concentrate or look for a specific vacuum leak? The boat also seems to get "stuck" in a fast idle, and continues to pick up RPMS from time to time. Especially running on the hose.

Cory
 

Dhadley

Supreme Mariner
Joined
Feb 4, 2001
Messages
16,978
Re: Vacuum Leak

They will idle faster out of the water because there's no backpressure in the exhaust.
 

BigNiner19

Petty Officer 1st Class
Joined
Jul 1, 2006
Messages
234
Re: Vacuum Leak

They will idle faster out of the water because there's no backpressure in the exhaust.

I knew that, but thats not what i'm inquiring about. I've messed with settings on my carbs and on my idle mixture screws...Messing with the timing helped...but I think it needs more timing. I just can't get it to want to idle with a lot of backpressure, and it doesn't like going in and out of gear/neutral (it will want to stall)

By the way, I just cleaned the carbs thoroughly, so im fairly certain this is not a "dirty carb" problem. I did experiment a little bit today though...with it running I sprayed some carb cleaner near the top carberatuer...and it ran better while I was spraying it (at idle) then it would immediately go back down to how it usually idles which is not so good. This is what has led me to believe I have some sort of a vacuum leak or something.

Cory
 
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