Thread: Help please
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Old 11-28-2018, 10:02 AM   #18
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Join Date: Nov 2011
Location: Grand Rapids, MI
Posts: 19
Default Re: Help please

Originally Posted by Tom Wesenberg View Post
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.
Certainly checking the conensor is a great idea, but I would certainly listen to Tom. His advise to me a while back was spot on - baffles had come loose in aftermarket muffler, causing blockage. Car ran great at idle, but no power and backfiring when under power.
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