I have a 40hp Force by Mercury. The boat is new to me but a 1995 model. The engine starts right up but it has a ping or ring, not sure, when at full throttle. Seems to run fine just kind of annoying. I am running 50 to 1 Quicksilver with premium fuel. There was some fuel in the tank when I got the boat, and not sure of the age. It only occurs at 85% to full throttle.
Any Thoughts?
Thanks

CAUTION!!!
Detination will distroy the engine! Use a good brand (Texaco,Chevron,Exxon) premium (High octane)fuel and keep using the good oil. It could also be an ignition timing problem. I have heard 2 strokes sound like they were pinging when they had a cracked reed valve. This can be just as distructive.
In any event, I wouldn't use it until I found out what was causing it and cured the problem.

look at one more thing. This happened to me on a 200 Merc. On the steering linkage there is a nut that connects to the motor. There was a washer on the bottom of mine and the nut was just a tad bit too loose and at 3/4 to full throttle I was hearing a ringing type of noise and worried the hell out of me. The mechanic said there was nothing wrong with the motor. One day I had my wife drive it and I laid on the back deck and finally saw it. About 1/16 of a turn and my problem was no more. Just thought you might want to check yours. I took mine to the shop just for them to check the motor and they said everything was fine both times. It did not do it every time I went out but did it probably 5 out of 7 times. I hope this is what yours is and nothing more. Good luck!

I will check it out Steve,
Thanks,