Engine knocking noise

Joined
Aug 11, 2018
Messages
3
I have a 2004 Yamaha f115 that has a knocking noise. But sound like something is tapping on the motor. The motor does have any powerless when I hear this sound an only does it when on plain typically. Some said it could be the exhaust an that it does sound like it coming from the power head . Any ideas?
 

99yam40

Fleet Admiral
Joined
Sep 7, 2008
Messages
8,851
Maybe the fuel has lost Octane(gone Bad) and the motor has preignition or detenation going on.
very bad for the pistons if it is

drain fuel from lines and pumps, Hook up a portable tank, and flush with new gas and then test run to see if that took care of it.
if so drain and clean the main tank and put fresh gas in
 
Top