"Mike Slater" wrote in message
news:knfZl.742458$yE1.158636@attbi_s21...
I was cruising along in my 24ft pontoon boat when I got a real surprise.
Somebody please tell me how and why I could be running wide open throttle
at my normal 5500 rpm and then suddenly the boat took off like a bat out of
hell running at 8000 rpms and 25mph??? I never touched the throttle. It
has never run that fast ever. After about 2 minutes it went back down to
5500 and never did 8000 again. Its a 60hp mercury Bigfoot outboard. It
has never done this before and I don't even know how it could rev that high
and go 25mph. Normal is 5500 and 17mph. What happened??

Mike
I wanted to try to close the loop on this issue and I think I can. I think
as someone stated, running "lean" can cause the engine to rev higher. I
looked at my inline fuel filter and the thing was empty when it did it
again. Today I replaced all the fuel lines to make sure no air was getting
in and it has not happened since. I am back to 17mph. BTW, I don't trust
the tach reading of 8,000 that I got because the reading is a little
"unsteady" despite no discernable (by ear) engine rpm changes.

I know that running lean can burn the pistons so whoever mentioned running
out of fuel (lean) as being something to check... THANKS.

Mike