I have a 2001 Argo Bigfoot with the 18 horse Briggs. The problem is that the rear cylinder burns much richer than the front cylinder. I am always blowing black soot out the exhaust pipe. The front cylinder burns perfect!!! I checked the valve lash and opening distance and it is fine. The compresson of both cylinders is exactly 90 psi each. When I have the air cleaner off I notice that when i goose the throttle, there is raw gas being blown back thru the carb. I don't think it is a carb issue because both cylinders run off the same intake and 1 barrel carb. I am wondering if there is a restriction in the rear exhaust pipe or valve that is causing the unburnt gasses not to be totally exhaled thru the pipes and blowing back thru the carb on the intake stroke. Has anybody had this problem????? I've had this problem since the day I bought it. I purchased this machine with only 17 hours on it and now I have 70. Any ideas would be great.
Mike, My Argo has done the same thing from day one also. I have to "goose" the throttle to let the engine clear it's throat before starting from a stop or it will stumble. Mine also blows the black soot, I ended up changing the back spark plug because of it - the machine would lose power when turning and bog out. And now it back fires when turned off. I love the machine and it's capabilites but am a little disappointed with the Briggs motor. I will probably take it to a lawn mower repair shop this summer and have the engine tuned correctly.
I have done the same thing. I am now burning a hotter plug in the rear and it at least doesn't foul out every few hours now. Mine also back fires after shut off. Unburnt fuel left in the cylinder I think. I am very dissappointed in the briggs but love the argo. I bought a john deere lawn tracter with a briggs last year and I'm not happy with that engine either. This month I am going to do some more diagnosis on the argo moter even if I have to tear it appart. I will fill everybody in. Any more ideas????
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