Why don't small engines, like in lawn mowers, have better mufflers to make them quieter?

Question

Why is it that all of those small internal combustion engines, like the ones on lawn mowers, pressure washers, generators, ATVs, and outboard boat motors have such tiny mufflers and make so much noise? I especially wish the lawn equipment was quieter--the noise can ruin a nice day. Why not just put on a bigger muffler like a car has to reduce the noise? Even just a few decibles quiter would be nice!

Answer 1

Fricken great question. I remember many a day cutting the lawn and being annoyed by the same thought!!

Answer 2

Expense vs. compliance.  Larger and quieter mufflers cost more to make.  But everyone wants a mower for the absolute lowest dollar, so the compromise is cost vs. the compliance with federal noise levels.

Answer 3

meanolmama is right.  In the case of ATVs, Motorcycles, etc it is usually a matter of choice for the owner.  But, in the interest of holding down costs, most lawn equipment engines are borderline horsepower wise for the application.  Mufflers restrict exhaust flow, which of course restricts fresh air flow to the combustion chamber, which in turn reduces horsepower.  I expect the manufacture's engineers have already considered the largest muffler they can use in each application.  Why don't you spring for a great big motor for your mower and you can put as big a muffler on it as you like.  

Answer 4

think about it..... drag racers don't have mufflers.. hot rods have pretty much straight pipes, yes?.... why?... cuz the muffler inhibits the free flow thru the engine.... cuts horsepower... slows it down, chokes it off, so to speak.... I don't know how to say it like a mechanic would, I just know that you get better  power and performance out of an engine when it's not mufflered....