Engine dies at idle

[txhorns0508]

I have a 1992 Johnson 140 outboard that dies at idle speeds. Should I just make the idle speed faster? What else could it be? Thanks.

 

[Xcusme]

Re: Engine dies at idle

Well. if the motor is idleing at the rated speed and it still dies, then a carb(s) rebuild would be order......
if the gas filters are clean.

 

[boobie]

Re: Engine dies at idle

What's the compression on it ? Is it running on all 4 cyls ?

 

[txhorns0508]

Re: Engine dies at idle

I haven't checked the compression but will do that as soon as I get a chance (hopefully one day this week) and get back to you guys. But it runs just fine at cruising RPMs (but it is pretty sluggish on getting up to speed), so I'm pretty sure all four cylinders are working at that speed at least.

On the idle speed - how do I adjust that? Ive looked in my seloc book and they didn't have any pictures or a good description, and I don't want to turn the wrong screw.

 

[txhorns0508]

Re: Engine dies at idle

Could be helpful to provide a little more background - the boat sat for a few weeks without being run and that is when the port engine started dieing at idle.

Also, I mentioned it is sluggish getting up to cruising RPMs, and that is definitely the motor, not the boat. When I push it the strbd motor gains RPM quickly, and the port one (the one that is dieing) climbs to about 3000 rpms or so then kind of stops, then after a couple seconds it finally keeps climbing up to 4000 rpm. So I guess it just feels really bogged down at lower RPMs, but runs fine at higher ones. This has been going on for awhile though.

 

[archcycle]

Re: Engine dies at idle

Could be a fuel issue. First check for restrictions like a kinked hose or a closed tank vent. You could also try swapping the fuel lines to the other motor and see if the problem follows. Easy and no tools.

Then you should check for a strong spark that jumps a 7/16 gap on a spark tester from an auto store. If you have spark then check for even compression.

If you have spark and compression and the fuel lines are ok then you've got clogged carbs. Pulling the plug wires while running might point you to the correct cylinder (port carbs feed starboard cylinders) and taking that one (or those) apart and cleaning it might solve your issue but if you've got gunked up carb in the port motor you've probably got 4.

Make sure you remove the idle bleed orifices (on the face of the carb) as well as the high speed jet in the float bowl behind the big drain screw and clean them out really well and blow all of the passages out with low pressure compressed air 30lbs or so.

 

[txhorns0508]

Re: Engine dies at idle

Thanks, appreciate the help and clear path to figuring it out. Will get on that this weekend.