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ac912 actin' weird (ie, HELP)


Mann

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I had moisture in the gas and my 9hp. Briggs acted like you describe. I didnt know at the time it had moisture but after checking everything electrical and finding it ok I took a shot in the dark and drained the tank and carb. bowl. With fresh gas it ran just fine. My 2 cents. Dick
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If it chokes up when you put it under load, it could be the governor spring is set to weak, dumps too much gas in when it starts to come under load. Just another idea.
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I have an AC912 repowered with a 16 hp Briggs. It began acting up lately and I woder if someone might have an opinion on what the problem may be. It will start and idle fine. If I crank up the revs it runs fine. The problem seems to come up when I start to mow or even move at all. I guess when ther motor is having to work instead of just run. It will cut out and backfire like crazy then it's fine again for a few minutes only to repeat the backfire episode. Sometimes it dies and sometime it doesn't. I figure the best way to figure out the problem is to ask someone who actually has some knowledge of small motors. Anyone out there know the scoop? Thanks in advance for taking out the time to reply. Brian Mann
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The problem could certainly be the points, condenser, or carb. It could also be a bad wire, switch, or cable. I would try a new spark plug first, and check the air filter.
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An additional thought.... Make sure that none of the switch cut-offs (pto, seat (may not have this depending on year), etc) is not faulty or "on the edge". My Sovereign was doing the same thing especially going up/down grade or over rough ground until I held down the seat (deadman) switch with an electrical cable wrap. Also, check your wiring. Had backfires when the rear light wire became freyed and grounded on bottom of the seat cover only when I was on it. Sit on the seat, turn on the light, short out the ignition switch/engine and blow un-ignited gas mix into the hot muffler - bang! Something to check.
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This is the unit I had to set the points while it was running to get it right, as I told you. The points were new, but I wonder if the points plunger might be worn. Its entirely possible that the guy that rebuilt it omitted putting a new one in. A good question would be , would a worn plunger cause problems like this?
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I know that a bad coil can cause this condition on larger engines (like a Chevy 350). Might be rare, but it happened on a grain truck I was operating. I've got a 912 with the Kohler 12 horse (short-blocked it) and I've never had this problem. Good luck in getting it solved! Dave
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Change spark plug if still no good change points and cond. if still no good coil could be weak.Also check valves for sticking esp exh vlv. and proper valve clearance.
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