I've got twin Merc 496 Mags with less than 100 hours on them. Twice in the past 6 weeks BOTH engines have died (one, and then a few minutes later the other). Both times were after long idle periods without running them up (marina cruising and getting fuel) and wouldn't restart for 5-10 minutes (would start rough 5 sec and die). Changed fuel filters and cleaned and tightened all the electrical connections. Mechanic is telling me BOTH the fuel pumps are bad ($$$) and they need replacement. Instead of 60psi, they are at 6 and 8 psi with good voltage to the pumps.

So here are my questions.
1.) What would cause BOTH pumps to fail at the same time? The mech says the pumps are overheating with the long idle periods. (???)
2.) Anyone else had this issue?
3.) Did Merc really build a pump that can't handle a long idle? (one end of Newport Beach harbor to the other is 45 mins! And that's without stopping to check out the giant Virgin Cat)
4.) Any other ideas as to what it could be that's showing itself like this?

Thanks all!

How hot is it outside? It sounds as though they could be vapor locking. Did the pressure ever come back up? Did they restart after a period of time that they could have cooled off?
Eddie

this is one of the reasons to run the bilge blowers. they are not just for startup but to move air thru the bilge when you are not going fast enough for it to flow thru on its own. people do not realize how hot it gets in there idling around for almost an hour.