Need help with '95 40 HP Mercury motor

[fishbuster]

My dad is looking at a '95 Mercury motor, Power Trim, 40 HP, oil injected. Runs/idles fine for 5-10 minutes, then when in full throttle, runs half speed or less. Motor hasn't been used since '98, and even then was used very little. Fuel/fuel filter were replaced, Seafoam added to tank, carbs cleaned. Still having the same problem. Any ideas of what we can do next? Owner is willing to correct problem.

 

[JB]

Re: Need help with '95 40 HP Mercury motor

Howdy, Buster.<br /><br />Sounds to me like it is running on one cylinder.<br /><br />If the compression is good it can pretty easily be fixed, but it might be costly.<br /><br />Don't buy it as is unless the price is VERY low.<br /><br />Good luck.