I have read all the threads from beginning to end regarding this issue.

Quick history:

I converted Starboard engine from carbed to Mercruiser 502 EFI. All used stuff. Motor has ran flawlessly under all circumstances. Hot, cold, long idles, after sitting hot, etc. etc.
I just performed the same swap on the Port side. Took it for a quick test drive and it ran great. Next time out I ran at cruise power for about 15 min. Shut her down and dropped the anchor for a couple of hours. Pulled anchor and idled for about five minutes, then Port engine died and would not restart. Opened valve at end of fuel rail, got nothing but air. Let it vent until mostly fuel came out. Then engine started back up, ran great under hard throttle, cruised on plane for about 30 min, then idled again for a few minutes and engine died again. I'm sure it would start up right now cold and run fine as long as I stayed on plane running at speed.

Possible options:

1. Switch vst tanks from one engine to the other. This would verify if the diaphram vent assy is the problem. Then replace both of them. Then just leave the system in stock form. I am not confident in this approach. I do encounter some very hot weather in the summer. I do not want heat related problems later on.

2. Install a cooler of some sort and loop it back to the VST. I was considering a power steering cooler, but I'm not sure if it has enough capacity.

3. Install a cooler, route the return line back to the fuel filter, that is upstream from the electric low pressure pump. eliminating the VST. (This seems to me to be the most fool proof option).

4. Route the return line back to the fuel filter without a cooler, again, eliminating the VST.

Note: Running the return line to the tank is not practical with three tanks.

I'm leaning towards option 3. I'm looking for any and all experiances with this issue.

Thanks,

Steve

Run the return line back to the water sep extra input. You may not need a cooler then, or you can easily add one later. A cooler will add much work as you have lots of water plumbing as well as fuel plumbing to do.

The rest of the story:

I removed the VST tank, mounted a marine high pressure pump in place of it, and ran the return back to a "T" fittingthat I installed on the suction side of the low pressurepump. It ran fine untill I shut it down and let it sit for an hour. Then started it and idled along for about ten minutes and it started to idle rough, but did not die. So I did make progress! Then getting on plane it did not run good for about 20 seconds, cleared up and ran fine all the way home.

So I installed one of these:

http://www.mrcool.us/fuel-cooler/mar...er-513451.html

on the return line and so far it has ran flawlessly. The fuel temp is definetly COOL. Both pumps and all lines are cold to the touch! And the engine looks much better without the VST tank.

Thanks for the advice.

Steve

Great news, sounds like a good solution. Should hold up even in the heat of summer. Only $75 for that cooler, nice.

another thing to check,,fuel pick up tube in the tank..i had a few crack where it threads into the 90..was sucking air at idle but on plane all the furl rush's to the back of the tank force feeding the suction tube..