500 EFI Issues. Wont Stay running......PLEASE HELP!!
 

I have twin 1999 500 efi's in my boat. I pulled the boat out of storage today and I went to go start it. It will run for about 1 minute then die......like is is out of fuel. I took off the fuel filter and it make a hiss noise like pressure had built up and the fuel filter was only 1/2 full. I refilled the fuel filter with fuel and it starts right up. Again, only runs for about 1 minute at idle and then dies. When I turn the key you can hear a whining noise like always. If I turn the key on an off a bunch of times (more then 10), the boat will start again but then die after 1 minute. Here is the most confusing part- both motors do the same thing!!?? I cannot figure it out. I think I am looking my marbles!! There is plently of fuel in it, new fuel filters, etc. What am I missing?? Please help......leaving for a triip in 1 week. Thanks guys.. Mike

Plugged tank vent? See how long it runs with the cap off.

this might sound silly but did you charge the battery,s?

dam good idea! but both tanks,maybe.

I can recharge them but they are charged enough to start the boat though.

I took off the cap and blew compressed air into the take to make sure the vents weren't clogged. There were not. :(

hook up fuel psi gauge on rail when it quits make sure psi is also dropping to make sure it is a fuel issue ,then i would hook the engine up to test fuel tank,if it still does it bad fuel pump,if problem goes away you have a restriction in the fuel line,probably in the anti syphon valve if it has one.The early 500 efi only had the electric pump while the later ones also had a mechanical pump which could also be your issue

Good info. The hiss will be from breaking a vacuum, not from psi inside filter. This means you either have an air leak before the filter/seperator - crack in fuel tank pickup, loose fitting, hose, filter oring - or a restriction like an antiphon valve sticking.

Filling the separator/filter and it running for a bit means from filter to electric pump to engine working fine.

Tighten all hose clamps, see if any fitting can be tightened a little more, and if that doesn't work....check antisiphon valve and then tank pickup.

MDGperformance- I do not have a fuel PSI gauge. Again, both engines are doing the exact same thing......what are the chances that both fuel pumps are bad? They are both electronic. Where is the anti-syphon valve?

Where is the anti-siphon valve? I have a 1999 36 outlaw.