422/425 exhaust muffler

[KMA]

I drilled out the misaligned holes as Tim suggested. It backfired the first time I shut it off after only running for a little while. The good news is that it didn't do it the second time I ran it, which was for even longer. So I'm still not sure how much it helped yet, but it definitely didn't hurt and was easy enough to do.

To stop my PT422 from burning my lawn when I stop for a few seconds or from kicking up ton's of dust when working in dirty areas, I decided to do something simple and cheap since I do not own welding equipment (yet). I picked up a 1 1/2" copper elbow at the hardware store today and drilled a hole through my exhaust tip for a bolt. I added another set screw to keep it from vibrating.

 

[Marks481]

Looks like it works better then what I did. I took a cast iron elbow, and with a little work with a file, I was able to shove it over the tailpipe (same orientation). It fell off last summer, and I haven't put it back on,

Last time I mowed, I think I burned a couple spots in the lawn. I guess it is time to find that piece of angle pipe.

 

[Red Zebra]

no difference in power. I still get some dieseling when shutting down, but the backfires were starting to worry me so it is nice that they are gone..

I may pull my exhaust and have look too.

I did discover that after a running the 425 long enough to kick on the cooling fan, I let it idle at about 1/4 throttle for about 5 min (long enough for me to blow grass clippings out of all the nooks and cranies after mowing) it shuts
down without a hic-cup.

FWIW


Jim

 

[KMA]

Okay, I used my PT a few more times since following Tim's idea of drilling out the misaligned exhaust holes and it hasn't backfired again. It does run-on a bit if I shut it down hot as Tim mentioned.

I did discover that after a running the 425 long enough to kick on the cooling fan, I let it idle at about 1/4 throttle for about 5 min (long enough for me to blow grass clippings out of all the nooks and cranies after mowing) it shuts down without a hic-cup.

Jim, I do the same thing normally. I also turn on the auxillary radiator fan I mounted to the side before letting it idle a few minutes. Then it shuts down fine. After drilling out the exhaust, I have been shutting it down quicker just to see what effect it had on the back firing.

 

[Red Zebra]

....It fell off last summer, and I haven't put it back on,Last time I mowed, I think I burned a couple spots in the lawn. I guess it is time to find that piece of angle pipe.

Let the mower find it!

 

[Red Zebra]

That's what my dad would have called "Southern Engineering". Beautiful!
It's where function meets creative problem solving! Love it!