Why does my muffler glow ?

[Green stripe wide frame]

today i got the belt ran on my 125 for the qa42a thrower and a ran it wide open for a few minutes and found the muffler glowing. i have never worked this machine since buying it, bought it not running. i did have the head off of this thing to see the condition, the piston is scored there is a peice of it echted away from where a peice of carbon fell i didn't look at the valves at this time. my thoughts are timing or a burnt valve. oh, at idle it does not glow

[johncub7172]

I don't believe those were the kind of cigarette lighters IH intended to use! My 161 in the 71 did just the same before letting go of the connecting rod. Rebuild or replace engine while you can?

[Darrell]

Sounds like you need to richen your carb. as that can be a lean indication. Turn the high speed screw out a little at a time.

Hope that helps !!!

[Juicybusa]

Retarded ignition timing will cause this as well.

[782CC]

You are seeing very high EGTs. The motor will not live long as that pace. Your piston comment indicates it has been a problem before.
Start with what is easy to check.
- Timing - slow timing can cause this easily. Timing is always the base to start with as it also can affect carb tune.
- Fuel - Lean can cause hot exhaust. given an adjustable carb it is likely a problem. This is a feel it out process and should look to the manual for tuning. if carb is gummed/ dirty the jet may not adjust in. One method is is... At WOT pull the choke on slowly. If the motor cleans up before it starts chugging on fuel and missing then you have a carb adjustment to make.
- Exhaust valve bent/burnt - Frankly this is already likely due to running such a hot EGT. But not always terminal. Best way to test this is to do a leak down on the engine. If you don't have a leak down tester, you can put compressed air into the cylinder thru a spark plug adapter (at TDC) and listen for air leaking from valves and rings.

[Cub Cadet 123]

My 104 did the same and shot a few sparks out on my cruise around the yard. For me, it was the carb adjustment as several have already mentioned. Looks like others have already given you good advice to follow. The carb adjustment is a simple fix and I hope that is all that it is for you, too.

Cub Cadet 123

[Yosemite Sam]

As you already know, the scored wall and eroded piston are not a good thing, hopefully you can get some more time out of it. About the only thing you can do (short of a rebuild) is make it run as cool and smooth as possible for the rest of its time.

The guys are exactly right... First thing, set your timing, next, adjust your carburetor and clean out the cooling system. Do everything you can to keep it running cool.

Keep in mind that it could come apart at any time. If it does, you stand a good chance of losing the block and maybe the crank too.

Good luck.

[J-Mech]

Originally Posted by Green stripe wide frame

.....the piston is scored there is a peice of it echted away from where a peice of carbon fell....

How can you see the piston is scored if you didn't take it out?

Sounds like it's running too rich. But it also sounds like the motor already has damage. I'm going with johncub, rebuild it before it goes.

[finsruskw]

I agree!! Do it now while you still have time. Otherwise, be sure and have your shovel handy!!

[Dave R]

Nope you are running it too lean. Gasoline is part of your engine cooling. As a rule of thumb with an aircraft engine, keep leaning the mixture during cruise climb as the rpm falls off, when at altitude, lean the mixture to max egt (at that point the engine will start to run rought) and then enrichen the mixture to cool off the egt about 50 degrees below max. Anytime you are glowing an exhaust pipe, you are too lean, which soon leads to disaster.

At least with the Cub Cadet you are on the ground and not at altitude.