Hello, I am new to the boating. I inherited a 20-foot boat with a Mercury 225 Saltwater EFI.
I am used to working on cars so i know my way around a engine. I bought the Mercury Service manual and am using it to help me get this engine running. The engine motor has been sitting for a long time.
I have changed the fuel water separator, while I was there I cleaned the VST [vapor separator tank].
The high-pressure fuel pump was stuck. I used carburetor cleaner to get that working again.
I changed all the grounds and cleaned them up.
I installed new spark plugs.
The injectors were stuck; I freed them too.
I finally got the engine to start but--this is where i need help--the engine will rev on its own. The primer ball will empty and the engine will shut off. If I re-prime the VST, the engine will start right-up and then do it all over again.
What will cause this to happen?