stalling motor / vapor lock ?

[endless summer kona]

I have installed a 350 mag mpi mercury , quick silver repower unit in my boat, it seems to run quietly and smooth though after about 10 minutes and cranking the rpm to about 2500- 3500 rpms it hesitates and stalls . After stalling it repeatedly over an hour or less it doesnt want to start for a while . Ive drained both tanks and added new fuel before installing motor. after i took fuel filter off and ran fuel pump for a second or 5 . it cranks over no problem.

 

[rodbolt]

Re: stalling motor / vapor lock ?

not starting and not cranking are two different subjects. as I understand it you have to remove the filter to get a restart. is that correct ?

 

[JB]

Re: stalling motor / vapor lock ?

I/O topic

 

[highaltitude]

Re: stalling motor / vapor lock ?

i would check the anti siphon valve first. a vapor lock condition could also exist.

 

[Reel Poor]

Re: stalling motor / vapor lock ?

Is there fuel in the filter when you remove it? If so how much? If not full, could be restriction in pick-up tube from fuel tank i.e. antisiphon valve or screen filter located in bottom of pick-up tube.

 

[DaveM]

Re: stalling motor / vapor lock ?

It is unlikely that you have vapor lock with MPI. I'm with Higha, I would first replace the anti-siphon valve if it has a few years on it. Next step is to look at the fuel pump and filter if you are suspecting fuel supply issues. Using an aux. tank may help in your diagnosis. Good luck.