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hi there I have a 11hp Briggs and Stratton from 1978 whoever owned it before me has hammered what looks like an exhaust and muffler from a push mower into the hole in the engine block the muffler is completely rusted out inside (The baffle plates) and is incredibly noisy as a result I have pulled and pulled and soaked it in wd40 but it still wont come out any ideas on how to remove it? Also is tere a cheap universal exhaust and muffler for one of these engines? thanks

whmtd said:

hi there I have a 11hp Briggs and Stratton from 1978 whoever owned it before me has hammered what looks like an exhaust and muffler from a push mower into the hole in the engine block the muffler is completely rusted out inside (The baffle plates) and is incredibly noisy as a result I have pulled and pulled and soaked it in wd40 but it still wont come out any ideas on how to remove it? Also is tere a cheap universal exhaust and muffler for one of these engines? thanks

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Apply heat to the muffler with a torch then use a pipe wrench to twist it off. If need be add a cheater pipe to the wrench for extra leverage. Make sure the engine is securely attached to the mower or a bench so you can lean on it pretty good if need be. When you get it off check and see how bad the threads are mangled on the engine. It might not be worth the time/money to try and install another muffler. Aftermarket mufflers are available just about everywhere small engine parts are sold. Just take it with you to make sure you buy the right size to fit back on the engine. Good luck.

FWIW those are standard pipe threads. If the threads are bad, you could always get a thread chaser tap to clean up

Replacement mufflers aren't that expensive, at least over here on this side of the pond. The important thing is to use a lock nut on the new one. The muffler itself should never be tightened in. It should be loose, and a lock nut should be used to make it tight. Clearly, the PO didn't know this.

Mini Motors said:

The muffler itself should never be tightened in. It should be loose, and a lock nut should be used to make it tight. Clearly, the PO didn't know this.

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Good important point.

Mini Motors said:

The important thing is to use a lock nut on the new one.

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Like said the muffler is pipe thread and you can use electric conduit nuts for the lock nut.

Ok update thanks for all your help I have managed to get the exhaust out now And the thread is ok so I will be ordering a new exhaust tonight:smile:

When I was short on mufflers, or in a have-to make do situation I would sometimes use a standard thread water pipe section about 6"-8" long and simply screw it in! Works great and not really that loud. Louder than a regular muffler, but hey...it won't burn out!! Has to be at least 3" long to keep the cold air from rushing back in and warping the hot valves. Easy to get on, easy to get off!