Fueling issue: Need opinions/ideas where to start troubleshooting
 

Got to East Chicago marina yesterday, fired the boat up on the trailer, and then pulled the trailer out. Boat idled while I parked the truck.

About two minutes after I got aboard and ready to leave, the motors sputtered and then died. Tried to restart both motors numerous times, but they would crank and then sputter and die. Both motors failed to start and stay running again. Had the boat out for the first time last weekend and it seemed to run fine... Anyway:

I removed, inspected and reinstalled both fuel filters which appeared to be functioning normally.

Also removed and inspected hose going to the mechanical fuel pumps from the fuel filter at the pump. Noted that the inside of the hose appeared dry, and no fuel leaked out whatsoever when it was disconnected.

All of my sherlock holmes powers of deduction lead me to believe I have some obstruction in the tank or activated some kill switch that I don't know about when I was installing my stereo (?) by accident....

Opinions? Other things to check? Power is 2 Merc EFI 502's on fresh rebuilds.

I'm going to pick up a fake lake weds so I can run this thing off the hose in my driveway and try to troubleshoot this.

Thanks in advance guys. I'm glad it happened on the ramp and not in the middle of the lake!!! :evilb:

what is a fake lake?

what year 502 EFI motors do you have? My '93 502s' did that exact same thing. When it is hot out, engine cover closed and idling (i.e. Fuel being heated up circulating in the small surge tank on top of the motor) the can vapor lock. I replaced the mechnical pumps on top of the seawater pumps and it fixed my problem. EFI 502s' don't have alot of problems, but this symptomis one of the ones it has. Good luck, and if it is the problem, it is a relitivley simple and cheap fix..... Mike

Rabbit ears for the water hose.

I don't remember what year for sure... 95's or so?

Thanks for the response. It was only 77 or so out and the engine hatch was open though...

I will definitely look into that though. Appreciate it, Mike.

Any other ideas?

it was hot I Havasu when mine acted up. As far as the year, the v-belt motors do not have the cool fuel. The serpentine ( gen6) motors do. Mike

does it act like it wants to fire up when cranking, or cranks with no sense of firing voltage? If not than you've got an ignition problem. If so then you've got a fuel issue probably pump. Is there an inline filter aside fomr the seperator?

If not for the ambient temp then possibly vapor lock?

Need to isolate whether it's ignition or fuel related before further guessing can be done in my opinion.

It acts like it wants to fire.

I didn't see another inline filter past the fuel seperator...

what he said....we've seen a few having vapor lock issues....need to cool the fuel......

Would vapor lock be an issue even if it's not that warm out and the motors are cool?