Johnson 150 Idle Problems

[dartman]

I have idle problems with my 2003 150, and I'm having trouble finding a solution. The difficulties arise when lowering the speed to idle in gear or out of gear. With the idle speed set at 750 or below, the idle speed will gradually lower until about 500 rpm where the engine will kill. This takes about two minutes, and it will not restart until I pump the fuel bulb. <br /><br />My theory is that there is insufficent volume of fuel being pump to the carbs and the level drops until the engine kills. However, it would seem that the greatest problem would be whenthe fuel system is most highly loaded at the top end, but I have absolutely no indication of a problem at max rpm. <br /><br />Could it be a poor pulse to the pump and how can I check it? Any other suggestions?

 

[Seasport]

Re: Johnson 150 Idle Problems

I guess you have checked your fuel lines for air leaks?<br /><br />Check out your timing sensor plate to make sure it is rotating freely and returning to home base under spring tension. Idle rpms are determined by the idle timing setting. A few people have reported sticky timing plates. This could cause idle problems. The plate was sticking on my motor and I freed it up using fine valve grinding paste.