Yamaha F80 backfire

racerx88

Recruit
Joined
May 18, 2010
Messages
3
I recently removed and cleaned all four carburetors to adress lack of idle. Upon reinstallation i noticed the engine was giving off a sputter like backfire that sounds like a compression release. I've removed each plug to test individual cylinders and noticed it sputtered less when cylinder 2 was removed. I did not rebuild the carburators and feel like the problem may be either too much air or bad fuel although the fuel appears to be fine. If anyone has experienced anything similar i would greatly appreciate your knowledge.
 

rodbolt

Supreme Mariner
Joined
Sep 1, 2003
Messages
20,066
Re: Yamaha F80 backfire

most likly its a lack of a 4 channel manometer and a yamaha service manual correctly set the throttles on reassembly, that and debris in the lines and carbs.
that motor is very touchy about fuel system cleanliness and the shutters being set correctly when reassembled.
 
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