Thread: optimax trouble

combustion engines need three things to work, compression, spark and fuel. Always check compression first then check spark, if those two thing are good then you have a fuel problem. This will help narrow down where your problem is.

I would recommend you get a fuel pressure gauge that reads over 100 psi, hook it to the fuel rail, key on not cranking should read 20-30 psi then jump to 80 when cranking/starting. If no pressure, high pressure pump inside VST tank is probably bad, if its been sitting a long time pump may be gummed up, I have seen a few pumps bad in my time

Opti Max, otherwise knows as "Opti-bomb". The best recommendation that I could give you is to take the motor to someone that has a computer. He will be able to plug it in and find out what codes it is throwing. You could throw different things at it and guess but the computer tells the tail. Those motors are/were notorious for throwing different fault codes all the time. I know that one of two year classes in that motor had coil recalls on them. I also know that some of the main issues with the motor was the impeller going bad due to a little known screen that needed to be cleaned. Most mechanics didn't even know about it. They would change the impeller (due to the computer codes) and the issue would continue due to low water flow. It was usually not the impeller that was bad but rather the screen needing to be cleaned...

One other thing, make sure it is getting air. You might be getting a tank vapor lock although I doubt it with it only running for a minute.

Thank for the input i just took to dealer and hope they can find the problem this may be the last merc i ever owen i havent been happy with it so far.