Vapor lock

[Yzpass]

I have read lots of threads about 350 mag mpi vapor lock everybody says to install the check valve my question to everyone is how can you install the check valve kit when you have a five point drain system? Thanks

 

[Grub54891]

Vapor lock is the fuel system. Nothing to do with the water system, unless the fuel pump is cooled by the water.

 

[Yzpass]

Vapor lock is the fuel system. Nothing to do with the water system, unless the fuel pump is cooled by the

 

[Yzpass]

Yes you are correct vapor lock is in the fuel system and yes it is cooled by water

 

[Yzpass]

Yes you are correct vapor lock is in the fuel system and yes the water cools it

 

[QBhoy]

I have read lots of threads about 350 mag mpi vapor lock everybody says to install the check valve my question to everyone is how can you install the check valve kit when you have a five point drain system? Thanks

To be honest, from memory, the drain system here, drains into a manifold below. Not sure if what you are trying to attempt is the thing to do or not…but I wouldn’t think it should be affected, if you put it upflow of the manifold it drains into. First I’ve heard of this being a solution to vapour lock, to be fair.

 

[Scott Danforth]

doubt you have vapor lock. the fuel pump on the MPI engine is not concerned about fuel pump temps and will push fuel thru regardless.

check your fuel pressure.

 

[QBhoy]

doubt you have vapor lock. the fuel pump on the MPI engine is not concerned about fuel pump temps and will push fuel thru regardless.

check your fuel pressure.

Might be right Scott. And it’s certainly not ever an issue I’ve known here in Scotland. But I have read occasionally that some 350 mag mpi in particular, with cool fuel…have apparently suffered it. Not sure I’ve read that this was actually the end diagnosed cause of the issue reported as such though. Who knows.

 

[Tail_Gunner]

What type of symptoms is this engine experiencing? Gas boils at approximately 160 degrees Fahrenheit, marine blocks simply do not run as hot as a automotive block.

 

[achris]

The check valve goes into the water line that is coming into the engine. It goes between the steering pump fluid cooler and the cool fuel pump assy...

#2 in THIS drawing.

Chris...

 

[Stinnett21]

My 5.0 MPI did this. The fix was exactly what Chris describes above. I think this valve stops hot engine water from flowing back into the fuel cooler.

 

[Stinnett21]

#2 in the pic.

 

[Yzpass]

The check valve goes into the water line that is coming into the engine. It goes between the steering pump fluid cooler and the cool fuel pump assy...

#2 in THIS drawing.

Chris...

I do have that could my check valve be bad how could I test it?

 

[achris]

Pull it out, try to blow through it. Should be very easy in the direction of flow, and opposite shouldn't allow any air through.

Chris.....