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How will my pushmower run if...

thatK30guy

thatK30guy

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...I remove the muffler completely?

Other than loud. :doah::haha:

Will it eat up or burn the valves due to lack of back pressure?

Do it or not? I think its plugged up right now as I've already changed the plug, wire and cleaned the carb out good.

I can see the neighbors poking their heads out their doors wondering what all the noise is coming from. :haha:
 
What kills an exhaust valve is cold air hitting a hot valve. So after many uses the exhaust valve will eventually burn. There is no problem to remove the muffler to at least check that it is your problem but i wouldn't continue to run it with no muffler.
 
Most of those motors, no matter how the muffler is originally attached, are threaded for 3/4 pipe. Many times when the stock muffler blew off from rust, I have screwed on some galvenized pipe with good effect.
Once made a muffler out of, in order from engine to air, a short nipple, 3/4 to 1inch adapter, 2 inch long 1 inch pipe, 1 inch to 3/4 adapter, short 3/4 nipple, 3/4 street ell.

The 2 inches of 1 inch acted as a resonating chamber which reduced the noise before reducing it back to 3/4.

There was no design involved, the muffler blew off, the hardware store was closed, I had a yard to mow, and some scrap pipe laying around.

Worked amazingly well. The noise level would change a lot with rpm. I suspect that the length of 1 inch was critical. At certain speeds, you would hit resonate frequency for that length. Person wanted to experiment, might do pretty good.

J.
 
I definitely agree with running at least a 6" Pipe, that should take away the threat of warping a valve.....although it may run a tad on the lean side.
 
I used to make a 3' pipe for my mini-bikes,they had a nice "rasp" at about 3000 rpm's..below that they sounded like a harely!..when you backed off the throttle from high rpm they would go "fraaaaaaaaaap" like a glass pack!..

My older brother used to take a air cooled VW tailpipe and braze a pipe nipple in them so they'ed fit our go-carts and mini-bikes,they were baffled and fiberglass packed and made a cool sounding muffler..I have made my own heavy duty tractor mufflers by drilling a bunch of holes in whatever size pipe screws into the exhaust port,until it looks like swiss cheese..then I'd make a 6-12" hunk of 2" pipe fit the smaller pipe by using thick large washers welded to the larger pipe and pass the smaller one thru it and weld it up..its quieter than a stock muffler and lasts a lifetime..
 
Put a 6" pipe on it and it still runs like crap. Turns out to be the carb. Any tips on getting these things clean and tuned?
 
thatK30guy said:
Put a 6" pipe on it and it still runs like crap. Turns out to be the carb. Any tips on getting these things clean and tuned?
Click to expand...

Well first thing first, what condition is the gas in? If its old or any possibility of water in it then drain it. Then drop the bowl off the bottom of the carb clean it out with carb cleaner and run a thin metal wire of some sort through all the little holes and ports. Make sure the o-ring is in place then put it back together.
 
Gas is new and fresh. I run the tank dry when I quit mowing for the winter. When spring starts back up, fresh gas goes in. Mower was running fine when I started it up and mowed the yard until it ran empty again. After that, it ran like crap. Not a fuel problem. I will mess with the carb over the weekend.
 
think maybe some kind of rust/particulate fell down into the carb when the last of the gas went out of tank?
 
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