Thread: Help please
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Old 11-27-2018, 07:10 PM   #15
Tom Wesenberg
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Join Date: May 2010
Location: Mpls, MN
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Default Re: Help please

Maybe we can call a firing through the carb a "front fire".

It would be rare, but a backfire could damage the exhaust or muffler baffle, and might cause an exhaust blockage. This will be noted by a smooth idle, but not revving up as it should, and the manifold vacuum will drop very low at open throttle. If you hold your hand at the tailpipe, you should feel a strong blast of exhaust when someone snaps the throttle open.

In the 70's and 80's I had to repair a few exhaust with double wall pipes, where the inner layer collapsed, and couldn't be seen blocking the exhaust flow.
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