Poor Idle

[huttoboy]

I have done some work on a 1993 Johnson 115 (TJ115TLETS). Head gaskets, rebuilt carbs, etc. Did all the things the manual asks for(sync, timing, etc) but at idle after about 2 or 3 minutes it will die. When starting back up it acts like it was flooded (this is on the water, on the muffs will idle great and not stall) Adjusted the float level and float drop per the manual. What did I over-look? Makes good power-RPM 5200 and 44MPH on a Nitro bass boat.

 

[Dhadley]

Re: Poor Idle

What spark plugs are you using?

 

[huttoboy]

Re: Poor Idle

I'm using Champion L77JC4 plugs gapped at 30.

 

[huttoboy]

Re: Poor Idle

Dhadley, I have read other places on the forum that a larger gap, say 40, might improve idle. Is that true for this motor? On the water the idle RPM is about 700. On the muffs the idle RPM is about 1000. <br />From what I have read on this forum this is in the correct range. I have done a decarb with Seafoam. Any suggestions? Thanks for all your help. <br /><br />Bill

 

[huttoboy]

Re: Poor Idle

Dhadley, what do you think about that 40 gap to improve idle. Does that hold true for this engine? I read in one of the forum topics that this might help but maybe that was just for a ceratain motor. And, by the way, congrats on the 10K+ posts. You've been a big help to so many of us novices. Thanks

 

[Silvertip]

Re: Poor Idle

If you adjusted the carbs running the engine on muffs that's the primary cause for it NOT wanting to idle in the water. Why?? There is no exhaust back pressure when running on muffs. Make your carb idle mixture and idle speed adjustments with the engine in the water.

 

[huttoboy]

Re: Poor Idle

Hi Upinsmoke<br />These carbs do not have any idle mixture adjustments. They have fixed jets. I set the cam/cam follower per the manual where the carbs both just start to open when the mark on the throttle cam is in the center of the cam follower. Idle speed, if my tach is accurate, says about 700 RPM on the water and about 950 to 1000 RPM on the muffs. I think this is about the correct range, according to the repair manual. I've had this problem for quite some time, even before I rebuilt the carbs. It's just one of those nagging things that you like to clear up. New plugs, too.