F40MLHY bogs down at high RPMs

[JakePDX]

This motor has been worked on by 2 mechanics and everyone is stumped. The carbs were re-built, taken apart and cleaned, and then cleaned again. They look syncronized and the fuel pump is pumping.

It starts immediately on 1 or 2 pulls, idles perfectly, but bogs down and nearly dies when I throttle up quickly. I can get high RPMs if I very slowly increase throttle.

 

[boscoe]

Did the motor start running poorly all of a sudden that resulted in the need for the carburetors to be cleaned?

 

[JakePDX]

Did the motor start running poorly all of a sudden that resulted in the need for the carburetors to be cleaned?

It was came on the boat that was just bought and is new to me

 

[boscoe]

That model is known to be problematic when it comes to the carburetors not providing sufficient fuel flow. One fix is to increase the size of the carburetor jets.

 

[boscoe]

Google Search