MerCruiser 5.0 MPI intermittent no start (fuel filter empty)

[Miss"T"Blue]

MerCruser 5.0 MPI serial number OW364510. No start typically occurs after engine has been run awhile. Suspected vapor lock. However, problem has occurred while attempting first start of day. Replaced Idle Air Control (IAC) valve but problem still exists. Only solution to re-start is to remove the fuel filter and fill with fuel and re-install. Engine starts fine after this procedure. When fuel filter is removed following no-start problem, filter is dry. Engine performs fine when running, plenty of power sand idles smooth. Any help / suggestions are appreciated. Thanks!

 

[Bondo]

Re: MerCruiser 5.0 MPI intermittent no start (fuel filter empty)

MerCruser 5.0 MPI serial number OW364510. No start typically occurs after engine has been run awhile. Suspected vapor lock. However, problem has occurred while attempting first start of day. Replaced Idle Air Control (IAC) valve but problem still exists. Only solution to re-start is to remove the fuel filter and fill with fuel and re-install. Engine starts fine after this procedure. When fuel filter is removed following no-start problem, filter is dry. Engine performs fine when running, plenty of power sand idles smooth. Any help / suggestions are appreciated. Thanks!

Ayuh,.... Welcome Aboard,... Look for a vacuum leak, or restriction, Upstream of the fuel filter....

 

[Miss"T"Blue]

Re: MerCruiser 5.0 MPI intermittent no start (fuel filter empty)

Ttt

 

[Miss"T"Blue]

Re: MerCruiser 5.0 MPI intermittent no start (fuel filter empty)

ttt

 

[Bondo]

Re: MerCruiser 5.0 MPI intermittent no start (fuel filter empty)

ttt

Ayuh,... I guess ya don't like My answer,..??..??....:facepalm:

 

[Miss"T"Blue]

Re: MerCruiser 5.0 MPI intermittent no start (fuel filter empty)

Ayuh,... I guess ya don't like My answer,..??..??....:facepalm:

Local dealer found the problem. Vapor lock. Thanks for your suggestion.

 

[Fun Times]

Re: MerCruiser 5.0 MPI intermittent no start (fuel filter empty)

Local dealer found the problem. Vapor lock. Thanks for your suggestion.

What did they do to solve the vapor lock?

 

[spdracr39]

Re: MerCruiser 5.0 MPI intermittent no start (fuel filter empty)

I am having a similar problem but I am leaning away from vapor lock. I tried bleeding the pressure off the rail only to find there wasn't any and the pump wont make any when it is doing this. Maybe if the vapor lock occurred on the tank side of the pump( not sure how that would happen) it would put back pressure on the anti siphon valve preventing fuel from getting into the line ? Sorry if this seems like a hijack not meaning to be really.

 

[Failproof]

Re: MerCruiser 5.0 MPI intermittent no start (fuel filter empty)

Local dealer found the problem. Vapor lock. Thanks for your suggestion.

You stated it sometimes occured while cool? As it it would not prime and build pressure when vapor lock could not have been a suspect at all. Would like to see a future report on this, as I do not believe the issue is solved. Hopefully it is however!

 

[Miss"T"Blue]

Re: MerCruiser 5.0 MPI intermittent no start (fuel filter empty)

Dealer installed MerCruiser fuel boost pump part number 862264A7. Google "MerCruiser vapor lock"
and you'll find Service Bulletin 99-7 that addresses this issue. Had the boat on the water with an ambient temp of 109 degrees without any issues.

 

[Miss"T"Blue]

Re: MerCruiser 5.0 MPI intermittent no start (fuel filter empty)

Had the boat out this past Thursday with family and friends waterskiing. Must have stopped and started the engine 30 times. Didn't have any starting issues. Convinced problem is resolved.