Won't Idle

[legend]

I just bought a 14' Flats boat with 92 Johnson 40 HP. Don't know much on History. I runs Great at Top Speed but will not Idle. As soon as I put it in Neutral, it Dies. Does this sound like Carburation or Electrical issue? I had a similar problem with an old Evinrude 70 and it turned out to be a bad coil. Does this 40 even have coils? Any help would be great.

 

[jtexas]

Re: Won't Idle

You have two coils, one for each cylinder.
What's the compression on this motor?

It idles ok after starting, *before* you put it in gear?
After it dies, does it start back up and idle ok then? If not, check for spark on both cylinders after it quits.

Sounds to me kinda like float valves leaking a little, flooding it out when you stop.

 

[tashasdaddy]

Re: Won't Idle

agree, a little trouble shooting goes a long way.

 

[legend]

Re: Won't Idle

Thanks for the input, The Compression 1s 140 on Top Cylinder,150 on Bottom Cylinder. The Engine would not idle when you had it at neutral. Again it runs great wide open, but when you go to put it in gear it the rpms get so low it dies unless you are really quick about getting it into gear and then giving it a quick throttle. I took the carbs off this weekend and took them apart and cleaned all orifices with a soak in gasoline and then copper wire and then carb cleaner. It runs a little better but it still sounds rough almost like the rpms increase and decrease on their own. I guess I should get a manual for it. Could it be electrical? Where are the coils located? Is it the 2 small Black Boxes on the Starboard side of engine? Thanks

 

[tashasdaddy]

Re: Won't Idle

did you blow out the pick up tubes in the center of the carbs. http://forums.iboats.com/showthread.php?t=244013

Ethanol and fuel lines
replace all fuel line with Alcohol resistant lines. Ethanol deteriorates, the rubber lines, then they start to sluff off on the inside, going directly to the carbs. Settling to the bottom of the bowl. Contaminating the carbs high speed jets. clean a rebuild carbs, flushing fuel line before connecting to carbs.

 

[jtexas]

Re: Won't Idle

also, see here:
http://forums.iboats.com/showthread.php?t=167352
for adjusting needle valves.

Wandering idle speed suggests the throttle lever is not butted up against the idle set screw (throttle cable adjustment). This is a step in the link & sync process, which will be covered in the service manual.