235 Johnson / Idle Cough & Die-Outs

[ob1jeeper]

Have a 1983 Johnson 235, that is giving me fits. Was told the ignition & carbs were out of synchronization, so I had that done. It's slightly better, but still won't idle for long periods...like when idling through the no-wake zones, or trying to dock it, or load it on the trailer, or..... you get the picture... The NEW spark plugs are dark black & oily after 3-4 hours of running this weekend. All operation above idle is "FINE". Cracking the throttle, so it will run smooth makes the sneezing and die-out problem go away, but it's sure hard to dock it, or load it on the trailer like that. Once it dies, it's hard to start, and has gotten to the point, that I have to open the throttle nearly WOT, to get it to start. FUNNY THING... It starts & idles like a champ, with the motor on the garden hose in my driveway...<br />I suspect it's too richly jetted, but the Official Johnson Dealer, say's it's got the right jets in it... ANY SUGGESTIONS?...

 

[Salty Dog]

Re: 235 Johnson / Idle Cough & Die-Outs

Check the coil grounds.

 

[rwise]

Re: 235 Johnson / Idle Cough & Die-Outs

ob1jeeper<br />about the only thing I have seen cause "sneezing" is the idle jets are to lean. anyway riching up the idle mixture stoped my old rude from sneezing!<br /><br />Richard

 

[CAPTBLACKSMARINE]

Re: 235 Johnson / Idle Cough & Die-Outs

IF YOUR MOTOR IS COUGHING AND SNEEZING IT IS MOST LIKELY DUE TO A LEAN CONDITION.I HAVE NEVER SEEN WHERE A RICH MIXTURE WOULD DO THIS.IT COULD BE CAUSED BY A LEAKING INTAKE GASKET,CARB BASE GASKET IMPROPER JETTING,CRANKCASE LEAK,OR FUEL LINE LEAK,ALSO IF I REMEMBER RIGHT BUT NOT CERTAIN THIS ENGINE HAS CHECK VALVES IN THE INTAKE IF SO THEY CAN ALSO CAUSE QUITE A FEW PROBLEMS SIMILAR TO THIS .

 

[ob1jeeper]

Re: 235 Johnson / Idle Cough & Die-Outs

Thanx for all the notes & Reply's... My experience with 4-strokes tell me that a poorly grounded coil, would cause MORE problems at higher rpms, but then again, I have minimal experience with 2-strokes, so I looked it over... All were good... ohmed out fine, with no changes even after removing all bolts, cleaning, and re-inserting.<br /><br />HOWEVER... I think I've located at least part of the problem... I fabbed up a run tank, using an old stock watering tank, and am now easily able to duplicate the problem with the boat on the trailer, and the motor dunked into the stock tank, with a hose running to keep it full (and cool) which gives me the opportunity to examine it closely while running... What I've found is a trace amount of fuel "seeping" from the lower carb. It appears as if it's being forced out under pressure, as the fuel is "bubbly... almost to the point of being foamy..." strange... the only thing I can think of is that it's by-passing the needle & seat, causing the fuel in the bowl to foam, and causing the bowl to overflow... Anyone ever hear of such a thing? I've only seen that once before on an old Ford I had as a kid...<br /><br />Have ordered (yes from the LOCAL DEALER) a full set of carb kits, and fuel line supply hoses for all three carbs, as well as the replacement diaphrams for both of the fuel pumps... Hopefully, replacing all this stuff, should help dry it out, and let the mixture get lean enough to keep it from sooting up the plugs, and clear up the stumble / cough / die-outs at idle...<br /><br />Thanx again guys...

 

[ob1jeeper]

Re: 235 Johnson / Idle Cough & Die-Outs

FINALLY FIXED... The problem turned out to be a small tear/hole in one of the crankcase check valve vent hoses... dry-rotted and cracked where it made a sharp bend coming off the "hidden" check valve behind the bottom carb. It purrs at idle like a contented kitten now. FINALLY...