90 HP Optimax Fuel system

[JDMorris]

I let my boat sit for too long and have gummed up the fuel system. I took the Vapor separator apart and cleaned it up. The boost pump had a lot of nasty gunk, I cleaned it up with carb cleaner and hooked it up to a 12v battery and could hear it running. the needle valve was stuck cleaned it up and got it working. The high pressure pump looked very clean but I still sprayed some carb cleaner in it just for good measure. I put it back together and the motor started right away. It ran for a few min's and then died. I am a novice on working on boat engines so I was wondering what should my next step to clean this fuel system up? Any help would be greatly appreciated.

 

[Chris1956]

Optimax is a complicated beast. Do you have a water separator on that motor? If so, change it. Make sure square fuel pump on block is working.

After that, it probably makes sense to put the air and fuel pressure gauges on the fuel rail and see what they say.

 

[JDMorris]

Thank you for the help. I think I got it fixed. I added some seafoam to the gas last night and started it, it would run for a min or two then die. I then let it sit for about an hour and tried to started it again. This time it ran like a champ! I suppose I got enough cleaner in the system to free up the parts that were stuck. I am going to take it out to the lake tonight and see how it does.

 

[Chris1956]

Best of luck. My neighbor had the same problem as you, however, 2 mechanics and $2K later it still won't rev up.

 

[JDMorris]

Have him try putting Seafoam in the gas. I finally got the chance to take my boat out last night it started on the first try and drove around the lake for about 45 min's. I had it going about 38 MPH for part of the time. The lake I was on is pretty small so I could run that fast for very long but it seems to be running well.