1999 Yamaha 200 OX66 Salt Water Series

Question
Just recently had my boat overhauled at the marina after 3yrs of layup, problem was engine dying at full throttle after 3-4 min.  They replaced the High Pressure pump and Gas separator.  Still dies.  Think it might be crud in gas tank or Tank Fuel pump?  Runs fine at lower speeds, also starts right back up when it dies at high speed.  Any ideas?

Answer
Hi Chris...Thanks for selecting the undersigned to reply to your question.

I'm not a mechanic but, I'm surprised the repair source didn't test the results of their efforts, otherwise, it's likely they would have identified the symptoms you have described and resolved them. Sounds as though you're on the right track. It appears there may be a restriction in the flow of fuel to the combustion chamber. In the event you've checked all lines and they're properly secure and in good condition, perhaps the fuel tank might be contaminated, so drain and flush it. On the other hand, the fuel may not have been stabilized while the boat was laid up for 3yrs, and adding a stabilizer to the fuel will improve the octane factor.

Safe Boating
Ron