Mercruiser 5.0 EFI won’t start after warm up

[Kschimm]

Hello: I am having a problem with Mercruiser 5.0l efi, 2003. Runs good but when I stop to swim for a couple of hours when it is hot outside, it won’t keep running after being started. We wait 10 minutes and it runs great. I tuned it up but it is still doing it. I know everyone is going to suggest vapor lock, but why then would it start and run normal after only sitting for 10 minutes? I have seen similar old posts but no one ever posted the final solution. Thanks for any input.

 

[Bondo]

I tuned it up but

Ayuh,.... Welcome Aboard,..... Define yer tune up,.....

When ya last changed the fuel filter, did ya inspect the Contents of the old 1,..??
I use a qt. freezer baggie,....

Very important diagnostic evidence inside ole fuel filters,.....
Especially in the current ethanol age,.....

 

[alldodge]

Motor serial number please?

 

[Kschimm]

Serial number OM636492

 

[Kschimm]

The tune up was completed by an authorized Mercruiser dealer. They changed the fuel separator filter (not sure if they checked it for water), spark plugs, distributor etc.. I will see if I can find the receipt and add more details. Thanks

 

[alldodge]

Serial number OM636492

Thanks, helps me narrow my search

It could very well be vapor lock since the motor is hot. Your model could have a boost pump if it has a Bravo drive, but does not if it has an Alpha drive. Next time it does it have a rag and small screw drive. Remove the shrader valve cap (item 19) off the fuel rail. Place the rag to cover the valve and use the screw drive to press in on the valve to release some pressure.

Try doing this at least twice after turning the key ON then back OFF without cranking the motor. This will build pressure and if there is air in the fuel rail, this will bleed it off. Once it does start, replace the cap

http://www.mercruiserparts.com/bam/subassembly/31849/8093/90

 

[Kschimm]

Ok thanks, I will let you know how it works.

 

[Kschimm]

It is an alpha 1

 

[Lukien]

Hello: I am having a problem with Mercruiser 5.0l efi, 2003. Runs good but when I stop to swim for a couple of hours when it is hot outside, it won’t keep running after being started. We wait 10 minutes and it runs great. I tuned it up but it is still doing it. I know everyone is going to suggest vapor lock, but why then would it start and run normal after only sitting for 10 minutes? I have seen similar old posts but no one ever posted the final solution. Thanks for any input.

Hoping that you could update us with your fix, I’m having what seems to be an identical problem on my 305 Mercruiser with EFI

 

[GA_Boater]

Hoping that you could update us with your fix, I’m having what seems to be an identical problem on my 305 Mercruiser with EFI

Kschimm is long gone. How To Start A Thread

Closed.