I have a 1996 Wellcraft Scarab with 454 Mag MPI serial #0F802426. I am having an intermittent problem with the motor shutting down after extended periods of time when its in gear at idle; it never does it at cruising speed or at WOT. The only way I can get the engine to restart is to crack the line going into the VST from the mecanical pump, I always get a lot of air out of the line and as soon as I see fuel drip, I close it off and the engine will start back up and run fine. Sometimes it will do it only once, but sometimes it will happen 2 or 3 times a day. I know it sounds like vapor lock, but it will do it even when the engine is cool. I have replaced the mechanical pump head; not the body; with an upgraded KE pump. It still did not fix the problem. I have checked all the clamps and fuel lines and fittings and all seem to be fine. Could the stock pump body be the problem?
Check to make sure your fuel tanks are properly vented. Check the fuel fill caps as well. It sounds like something is just not allowing fuel flow and it is usually air if the pumps are working. There is also a small screen filter on the electric pump inlet on some serial numbers. The only other thing you can do is check the fuel tank fittings. They have a check ball in them that often get stuck. We usually pull those, clean them then put a tid bit of Lucas Oil Assembly Lube on the ball and they usually work fine for a bit until the ethanol eats em up again. Thanks
We have also seen the distributor module act up causing this issue as well. The internal transistor gets intermittent and tells the ECM to shut off. It usually happens more often when ambient temperatures are hot!
Check it out if the problem persists.
Have a similar problem with a 1998 502 no vst, Cool Fuel. Also does not have the extra fuel pump. Happened twice the other day when it was 120. it would start for a second or two and then die. There wasn't really anyway to cool it down. Took messing with the throttle both times to keep it running. Any suggestions.