Side mounted fire starter. Red Hot exhaust

[Goose1776]

Yeah, I’m aware that engines that are being worked can make the muffler glow when looked at when twilight/dark. Around here back in the day when farmers used to full till the ground, they would do allot of their plowing at night after the cows were milked. With some tractors The muffler would get red from the engine being worked, tilling that ground.

I’m curious as to what Terry’s opinion is on your pt muffler getting red?

He said it was pretty much normal


I’ve been using the 1430, and haven’t had time to look into the 425 anymore, to make sure everything checks out, will probably look into it more by the weekend

 

[Goose1776]

Normal or not,
I had to know what the inside of the muffler looked like. So I Cut the PT425 muffler apart to see the internals

Will make some modifications to allow more flow
I already drilled out the manifold that was
mis aligned,
I will say, it was all welded up good. LoL

 

[cqaigy2]

My nephew made a new exhaust system for my Robins. He used stainless milking tube for the pipe and a fire extinguisher for the muffler. The pipe from the cylinders was all sweep 90 into the main tube and sweep 90 toward the rear where the muffler was. I have to say, he did a pretty good job of it. Much quieter and seemed like things were cooler inside the tube.

 

[Goose1776]

My nephew made a new exhaust system for my Robins. He used stainless milking tube for the pipe and a fire extinguisher for the muffler. The pipe from the cylinders was all sweep 90 into the main tube and sweep 90 toward the rear where the muffler was. I have to say, he did a pretty good job of it. Much quieter and seemed like things were cooler inside the tube.

Sounds like a good setup
If my mods don’t work on the factory muffler as well as I want. I’ll try something like that.
If nothing else, just to lighten the weight of the darn thing.

 

[joshlee]

So, your not seeing anything change to the red hot color anymore, I take it?

That’s awesome how you found someone to makeup a custom exhaust for that

 

[joshlee]

My nephew made a new exhaust system for my Robins. He used stainless milking tube for the pipe and a fire extinguisher for the muffler. The pipe from the cylinders was all sweep 90 into the main tube and sweep 90 toward the rear where the muffler was. I have to say, he did a pretty good job of it. Much quieter and seemed like things were cooler inside the tube.

That’s awesome If I had a 425, that would be the way I would want to go.

 

[cqaigy2]

I finally took the time to find the thread. PT422 Muffler Mod Fair disclosure, i don't have that engine anymore, replaced with a Kohler (25hp) <- best mod to date on my 422.

 

[Goose1776]

Put on a factory Kohler exhaust manifold to a stainless 1.5” elbow, and a junk open pipe motorcycle muffler
It still glows red at the elbow
Which is exactly what Terry told me would happen
So the hot exhaust isn’t caused by a restriction
Everything on the engine checks out, and it’s only at 13 hours
but I still don’t think this is normal
Note:
This pic is taken at night, just looks bright due to camera flash

 

[m5040]

IMHO it is just the nature of gasoline engines. Think of your fuel consumption to get 25 hp and compare to what my PT1460 uses (<10 gallons in 10 hours) for 60 hp. It is waste heat going out the exhaust.

 

[deezler]

I've never had or even seen a PowerTrac, but as a mechanical engineer with a day job of dyno testing internal combustion engines, I will add my 2 cents.

That is not normal. Your exhaust gas temperatures are clearly way too hot, and that looks downright dangerous.

Sure, on a dyno torture test we can also get entire exhaust manifolds, turbos, and exhaust pipes glowing bright red here at work. But thats at sustained peak power conditions on highly boosted engines. A naturally aspirated Kohler 2-cylinder loafing around should not be anywhere near that hot. The only time I would call that acceptable is after a full hour of dragging a plow through soil on a hot summer day, or similar punishing work.

Multiple things can cause excessively hot exhaust gas temperatures. But ignition timing is an obvious suspect, valve timing another. Exhaust restriction would be also be one, but looks like you already answered that question. I know it would be obnoxiously loud, but did you try running with no muffler at all, just to see?