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post #1 of 3 (permalink) Old 08-30-2010, 10:28 AM Thread Starter
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17 HP B&S Backfire


I have a Murray Wide Body with the B&S 17 HP Twin II I/C Model # 42A707. For the past 2 years this thing has been back firing when I shut it down. Before shutting it off I wait for approx 1 minute at the lowest idle with the blades disengaged. That does not help. I have checked and the choke appears to be fully open. I can tell when it is going to back fire because the engine when nothing is engaged will idle up and down on it's own.

What I have done.....I was told by an older gentleman down the road that Briggs had a carb problem with this series of engine. He told me to loosen the screws holding the float bowl to the carb, then push the bowl as far forward as possible, then tighten the screws. This seems to work every time, but I do not know why, or what the real problem is. Anyone know what might be going on with this thing...........thanks.
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post #2 of 3 (permalink) Old 08-30-2010, 01:30 PM
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If the engine is running a little rough. Adjust the valves (use owner mnual),then remove carborator and blow through ports and all openings with air (gently)replace carb on engine and see if this helps. If not then it is probably time to rebuild or replace carb.
Hope this helps!
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post #3 of 3 (permalink) Old 08-31-2010, 12:12 AM
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If it's one with a fuel solenoid valve on the carb, I think those are supposed to be shutdown at mid throttle. Might double check your manual and see which method it recommends.

Mark - 2002 John Deere LT150H

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