I bought a 1990 40hp 4 cyl a couple years ago that still has idle issues----in spite of all the things I have done to it. Starts fine, idles fine when its not fully warm, and runs great at medium or full throttle. I go out to troll for big fish and it will idle for for a few minutes, and then will act like its running out of gas. Quits, and you need to put it on fast-idle and choke it to get it started. And it wont idle after that.
I have rebuilt the carbs and fuel pump. It has a new gas tank, fuel line and bulb, and fuel filter. Of course, plugs are new. Other stuff I have done include new Ignition Module and Trigger, and disconnecting the oil injection. (Not all of this was done to fix the problem). But none of this stuff made any difference
Have had Merc's for years and have troubleshooted all kinds of stuff before, but this one has me baffled. Could I have a cracked plastic fuel pump case that opens up when it gets hot? Could it be a crankcase gasket that opens up when warm?
Anyone have an idea? What am I missing here?
I have rebuilt the carbs and fuel pump. It has a new gas tank, fuel line and bulb, and fuel filter. Of course, plugs are new. Other stuff I have done include new Ignition Module and Trigger, and disconnecting the oil injection. (Not all of this was done to fix the problem). But none of this stuff made any difference
Have had Merc's for years and have troubleshooted all kinds of stuff before, but this one has me baffled. Could I have a cracked plastic fuel pump case that opens up when it gets hot? Could it be a crankcase gasket that opens up when warm?
Anyone have an idea? What am I missing here?
