I've looked at those, but my sender looks like is a threaded unit. Not the standard looking sender with a flat mounting flange

Nailit, so teeing both return lines together to a single hose didn't cause any issues. I was afraid there would be some type of fighting between motors doing so. That would make it so much easier

My 502 mpi w/VST vapor locked several times a few years back and it was mainly ethanol and winter fuel mix. Filled the boat up at the local gas station before putting it away for the winter. Managed to get most of the gas burned and filled back up with pure gas. I only use non-ethanol fuel now and so far no issues. I do make sure after running on hot days to do a bit of idling to cool the engine down, but so far so good.

I think that's a key point, idle down after a run. I've always done that, idled around 1100 for a minute or two before shutting her down. It's enough to move the gauge south and has to help getting cooler water ingested before the heat soak.

I've never run anything but E10 or whatever they're pumping at the quick stop. No ethanol free stations around here.

I was told that when I bought the boat, but twice last summer after doing so no start. Once I was idling into a no wake bay, long and narrow it crapped out. 15 minutes later starts right up and golden. There is no rhyme or reason to when it occures. The only difference I could see was it was at a lake 6 or 7 hundred feet higher in elevation than I normally boat at.

That sounds like the ICM crapping out. Or at least the way mine did.

I'll check that too, but after returning home it only happened once the rest of the summer, is there someone on oso that can line me up with a merc manual?

Agree with Hook'em, this would be another issue. Vapor lock happens after running and the engine has stopped and heat soaks into the fuel system components. If after sitting it starts up and as you idle back out of the cove it then dies

Twice since I've owned this boat I had to depress the fuel pressure check valve (looks like a tire valve) on the front of the fuel rail to release the vapor. Actually, I'm amazed how much vapor comes out before fuel. Afterwords, starts right up and keeps running. Kind of embarrassing though. Learned to idle with hatch open slightly like others have mentioned since.

Unfortunately, no ethanol free gas around here.

In stead of raising the hatch, just run the blower.

So far as non-ethanol gas, here in KY I'm starting to see it at the corner station in Premium. The inland lakes I boat in many, but not all have non-ethanol gas at the marinas for mid and premium grades. Locals know which marinas have it. I only need 87 octane but will run the mid grade do to ethanol.

I've had the problem even with long idles thru marinas and back into the coves and engine hatch cracked. Made no difference. I also run the blower all the time. Have thought about bleeding the the fuel rail by the valve also, but had this ugly thought run thru my mind....if it's so hot in there to vaporize the fuel in the lines, no so sure I wanted to bleed it onto the top of said hot motors. Was going to do this the last time we had the boat out, but there were always other boats tied up next to me, so I decided against using that time to try it.