2004 merc 50hp efi starts and stalls wont stay running

[MRJ82]

I am hoping you fine gents can help me trouble shoot my issue here. I have a 2004 merc 50hp efi That starts beautifully, but shuts off after 3 sec. I have replaced both fuel filters, completely cleaned vst tank, regulator screen, installed new high and low pressure fuel pumps. Shoots right up to 42psi. No leaks in fuel lines. Primer bulb is stiff and stays stiff. When it shuts off, it will not start back up unless I hold the choke in, but then dies again. If I keep the choke pushed in, it will run for about 10 sec before sputtering out. Will stay running on started fluid. I am at a loss of what else it could be. what else is there to check?

 

[cyclops222]

You may have a vacuum in your gas tank? Unscrew the gas tank cap completely to be sure. If it is a high vacuum condition. Make sure all fuel line connections are fully seated.

 

[MRJ82]

You may have a vacuum in your gas tank? Unscrew the gas tank cap completely to be sure. If it is a high vacuum condition. Make sure all fuel line connections are fully seated.

I forgot to mention I tried that as well to no avail

 

[MRJ82]

Any ideas are welcomed. We have a beautiful week coming up, and I would love to spend it on the water.

 

[airshot]

The oldies were so much easier to trouble shoot.......you have my condolences..

 

[cyclops222]

As many have noticed. I do not attempt any F I or computer motors,
I am a dinosaur.

 

[dingbat]

A choke on an EFI?
Never heard of such a thing.

Injectors are very sensitive to fuel quality. Must a 10 micron filter to avoid problems.

10 micron filter?
When was the last time the injectors were sent out for cleaning?

Have you monitored fuel pressure while engine is misbehaving?

No beep codes?