Vapor lock 7.4 mpi Sundancer 340

[VinceR]

We have a 2001 340 with 7.4 mpi engines. We could not do a hot start on the starboard engine after the fireworks on the fourth. We understand that there is a vapor lock problem on these engines. Have any of you experienced this problem? If so what was the solution? Thanks Vince

 

[fc3]

Never saw vapor lock on either of my 7.4s. Even with air temps in the 100 degree range and water temps around 90 did Just Ducky have a vapor lock problem.

 

[67vetteal]

Change out your Ignition Relay. They get Cranky with time. The Fuel Pump uses the same Numbered one and I'd change out that one to.

 

[sotaman]

I had the same type of problem on my 1996 7.4 EFI. I finally found a mechanic that told me the VST tank was no good. I never heard of a VST tank, but I was told it is in the feul pump and it keeps the pressure up going into the injectors. Anyway, the estimate to replace it was $1877. After I stopped choking, he said he would take it apart and see if he could fix it. He did and charged me $160. I have not had any problem since.