Merc 502 stalling/dying on acceleration after idling for awhile

[Big Block Power]

When I did my engine compartment temperature test the blower made no difference. On / Off temp inside the engine compartment remained the same.

viewtopic.php?f=44&t=471&p=7805&hilit=Fireboy#p7805

Really that's interesting. It was interesting reading that merc bulletin that they made it a rule that the temps can't go over 175 in the engine compartment after a certain year.

[thunder550]

Thanks for the info Driller, I'm not surprised that the blower didn't change anything. Hot air rises, and the blower is designed to suck air from the bottom of the engine compartment where fuel vapor would sit. Any fresh air that was drawn into the engine compartment would most likely be cooler than the other air, which would cause it to sink to the bottom and get sucked out before the hot air as well. Best thing I can do in that regard is to open the engine hatch, which would immediately let the hot air out.

Honestly 175 degrees is REALLY hot...I can't see the ambient air getting that hot without causing problems with other wiring, blower tubes, life jackets, all the other stuff that sits back there around/next to the engine. Maybe the temp directly above the engine (where the VST sits), but not everything.

I'd be really interested to find the temperature inside the VST, since that's where the problem does (or doesn't) occur. I'd actually love to stick both a temp and pressure probe in there and get readings before and after moving the return line. No idea how to make that work though. Either way, I think I can make the line return to the tank for < $100 and have it be easily reversible in case I needed to remove it for whatever reason.

[Big Block Power]

Shoot it with a infer red guage.

[Big Block Power]

Let's redo your swim platform you don't like it anyways

[thunder550]

Good idea on the IR gauge! I could use one of those anyway

[thunder550]

Took a look at the fill hose, it's 1.5" ID. I think this is how I'll end up rerouting the return line. It's circled where it currently goes back to the VST, will get an adapter to screw on to the line and a plug for the VST, run it along side the other hoses, then down to the fill hose with the tee spliced in as indicated. Anyone see an issue with this?

IMG_20180421_090407.jpg

[thunder550]

Maybe I would be better off returning directly to the tank instead of cutting the fill hose, not sure about marine standards for fill hose and if splicing something in would cause issues with fuel vapors in the engine compartment.