1996 Johnson 225 stalls low idle

I have a 1996 Johnson 225 outboard Ocean Runner Model # J225TXEDE with Champion QL78YC plugs installed. The problem is it Starts and runs good. After idling or running at slow trolling speeds for awhile it will shut down, other than that the engine runs great. I have replaced the main fuel filter and the inline fuel filter. Any suggestions as to what my problem is?

Re: 1996 Johnson 225 stalls low idle

Shaps.... Try a set of Champion QL77JC4 s/plugs with the gap set to .040 . Let us know how you make out.

Re: 1996 Johnson 225 stalls low idle

I actually tried those plugs gapped at .035. That is what the Champion book called for still had the same problem. I called Johnson and was told they recommended the QL78YC gapped at .030, which was previously installed. I believe I need the QL78YC plugs because they run hotter and their is a little oil on the plugs. What will the difference in the gap do? Any other ideas? I have read about other model Johnson’s having a similar problem with a recommendation of changing the squeezable clamps on the fuel line to a hose clamp, because they could possibly causing air leaks. What do you think? I can try as many suggestions as given this weekend and all is appreciated.

Re: 1996 Johnson 225 stalls low idle

You definately want the QL78YC's and .030" is the correct gap. OMC issued a service bulletin (95/96 time-frame) which listed all the spark plug recommendations. It also refers dealers to the current edition of the "Dealer P&A Catalog" (for future reference).<br /><br />Gaps were also changed to .030" - this is to reduce the likelyhood of false alarm signals causing the engine to go into S.L.O.W. (self-protect mode). I was told the engineers discovered spark plug gaps in excess of .045" could cause this - therefore if you start off @ .040"...<br /><br />You might just simply verify your engine's idle speed is correct. The spec is 650 +/- 50 rpm, in the water, in gear, NOT tied to a dock. Personally, I favor the +50 when I set them up. DO NOT rely on the in-dash tach, use an accurate "shop-type" inductive pick up tachometer when setting idle speed.<br /><br />When the engine stalls out, what do the spark plugs look like?? Is/are any one (or more) wetter than the others??<br /><br />-John

Re: 1996 Johnson 225 stalls low idle

John thanks for your reply, I will try your suggestion this weekend. All the plugs looked the same when I removed the old QL78YC. When I installed the QL77JC4 and pulled them 2 were wetter than the others, but I am assuming this happened because they are not as hot as the QL78YC. I replaced theses plugs with the old QL78YC. I just bought new QL78YC and will replace them this weekend.

Re: 1996 Johnson 225 stalls low idle

RPM's are fine and put in the new plugs same result. When the engine stalls all the plugs look the same. Now finding another problem, the engine is surging when going at high speeds. This may have been happening before I haven't had it out in the ocean since the stalling started. Could these be related problems? Any suggestions?

Re: 1996 Johnson 225 stalls low idle

Adjusted the idle on one of the carb no longer stalling. I changed some of the squeezable clamps and tightned the rest engine no longer surging when going at high speeds must have been air getting in the lines. Thanks for all of your help.