Stalling after running at 25mph for several minutes

[jeep8589]

This one has me baffled. My boat runs fine most of the time. The problem I am having is that if I run at about 3000 rpms or around 25mph for several minutes and then throttle down to an idle the boat dies. It is then hard to start. The little switch that kicks the motor out for a second when taking it out of gear is not the problem. It will run all day at 25mph and runs at WOT with no problems either. If I only run at 25 for a short time and then throttle back it doesnt do it. It only does it after cruising for a while at a constant speed. Any ideas, or has someone had similar problems. Oh yeah, it is a 1993 3.0 mercruiser 130hp.

 

[Mahoney]

Re: Stalling after running at 25mph for several minutes

Only guessing, but from reading many other posts, it sounds like it could be due to fuel heating. <br /><br />Can you try running with the engine cover opened and see if that results in the same symptoms? That would tell you right away if your fuel lines might be heating the gas up so much that when idling back down and the carb isn't bringing in as much cool fuel from the tank, that the carb is getting some vapor instead of liquid fuel.<br /><br />Just a thought, and it wont cost you anything to check.