Mercruiser 5.7 efi cuts out

[ridinspurs]

I start my boat cold, runs great. I can run for hours and runs great. When I turn it off for an hour to swim, I start it back up, starts fine. I go to full power and it dies out before it goes to full. After a few attempts to start it, it starts and runs fine until I shut it off and let it sit for a while. then same thing. Almost like it's heat related.

 

[achris]

When was the last full service? I would start at the basics, make sure everything is right.... Here's my list...

1. Compression tests.
2. Check spark plugs, replace if needed.
3. If points, replace, along with condenser and rotor. Check and adjust, if needed, points cam dwell angle.
4. Inspect distributor cap, rotor and leads, replace if necessary.
5. Check spark quality (needs to be a nice BLUE spark drawn over 1/2").
6. Set timing. Check timing advance is working correctly.
7. Check/change fuel filters and check that the fuel system is not sucking air.
8. Check fuel pump pressure.

If doing all this doesn't show up a problem, or cure the problem, then start with the troubleshooting...

It sounds like a filter problem, but let's get everything else sorted first.

Chris......

 

[alldodge]

Being a EFI I would say this is classic vapor lock. Run your blower for a while after you shut it down and idle the boat for a bit before you shut down to try and cool things down. There is a fix but it will require a fuel return line back to the tank

 

[thumpar]

What is your serial number. Merc has mad a lot of changes to EFI over the years.

 

[ridinspurs]

Serial # is OF431773.............thanks guys!

 

[thumpar]

You have the same system I have. It has the VST which can still vapor lock if it is hot. One thing to check for is the small diaphram in the lid of the VST tank. They wear out and just let fuel through. I could see through mine. It is #6 in the pic.

 

[ridinspurs]

Thank you, I'll give it a shot.