Craftsman 18.5 intec
After mowing,started losing ppower and muffler got vvery loud,removed mmufflers
And shook it, can hear baffle
Ratteling, could bad muffler cause low power problem?Does this eengine need bback pressure to run properly?

Hi,
Bad muffler is just that. Replacement is warranted if not in warranty. Backpressure is usually not an issue, so you may well have another problem that you have less chance of hearing a symptom of with that muffler.
Peace,
Clarke