Missfire and smoke on 15hp Evinrude

[mattjeanes]

Hi guys.<br />I've just put my 1974 15hp Evinrude back together after dismantling just about everything. It started easily and ran well at first but after a while it started to get more smokey and every few seconds it missfires,sometimes with a slight backfire, almost stops and then runs OK for a few seconds before doing the same again. I'm running 25:1 oil at the moment which I guess may account for the smoke but this missfire used to occur before the rebuild on 50:1 so I can't blame the oil for that. I've got new coils, and have done a full rebuild of the carb but the other ignition parts are untouched as they looked OK and I was feeling poor after buying gaskets, coils and bushes. All suggestions gratefully received!

 

[DJ]

Re: Missfire and smoke on 15hp Evinrude

Matt J,<br /><br />Is this a misfire or a backfire "sneeze". A backfire or sneeze can be caused by a couple of things.<br /><br />1. The mixture (gas to air) NOT the oil to gas mixture is too lean.<br /><br />2. The timing is off. Is the flywheels seated and torqued correctly?