[CJ-8_Jim]

Somehow, I never noticed this until now. Did I just miss it or is there something more sinister going on?

After an hour of cutting grass, I drove it into the dark garage and noticed the muffler and both lead pipes glowing a full orange (blaze orange).
The entire exhaust subassembly was an equally intense orange.

Is this normal? Or do I have a restriction/obstruction somewhere?

NOTE: Lately, it is sluggish cutting grass up hill and will skip when warming up.

Tail pipe seems clear.

 

[jsoluna]

Most common causes of the exhaust glowing:

Incorrect Ignition Timing (unlikely)

Lean Mixture (more likely)

And when you say it will skip when warming up - can you elaborate?

 

[rscurtis]

For the benefit of the uninitated like myself, which engine are we talking about here?

 

[CJ-8_Jim]

All - should I assume a glowing muffler is not normal?

Lean Mixture (more likely)

I'll look into that. However for other reasons, I've suspected I've been running rich, no lean. Specifically:
- Not the cleanest air cleaner (though I remove grass/dust buildup every 2-3 mowings from the pre-filter)
- Black soot on a white cloth after 1 second or so in front of the exhaust pipe.

However, you do have me thinking -- that is, that maybe it's running lean due to a head gasket leak. (However, both exhaust lead pipes were glowing equally orange).
~10 hours ago I replaced the #1 cylinder head gasket because I had a blowout. At 6 hrs I rechecked the headbolt torque and all was fine. Head mating surfaced looked good after scraping with a wood shim and I assumed it was good since the engine had only ~50 hours at the time.

And when you say it will skip when warming up - can you elaborate?

At full throttle after starting, a cylinder will miss 1-2 times per second until it warms up. I should play around with it to see if I can figure out which cylinder by momentarily disconnecting one spark plug at a time.

Also FWIW upon starting when cold, it sounds like I have an exhaust gasket leak. Once it warms-up after 5 minutes, it goes away.

For the benefit of the uninitated like myself, which engine are we talking about here?

Kohler Command.

I and two other guys in my sub-division have had nothing but problems with Kohler Commands. One guy spent $2500 on engine repairs over his 5 years of owning his ~2005 GT2500-series

We all ove the Cub Cadets, but the Commands do a disservice to the tractor.

 

[diesel_nut]

Dirty filter will cause it to run more rich. The hot running of most newer engines of all kinds is due to EPA regs. Most all people that buy dirt bikes nowadays, IMMEDIATELY re-jet them so as not to have a melt down. Many new dirt bikes barely run because of the lean jetting. Crazy, but true.
Our own engines are showing problems from this. Too lean!

reminder to self: don't clean the airfilter(too clean anyway)

You got me thinking here. Just saw the restore on the CC100 (with the up-turned muffler ). If you added another muffler on the exhaust it would cause it to run more rich (and be that much quieter). Hmmmm. I have doubts as to whether the jets in these barbs are replaceable.

 

[1050Bolens]

Could be one of many things.

Personally I would take both valve covers off and check your valve clearances.

Had a couple V-Twin engines that were running HOT and it ended up being,on both of them,exhaust valve wasn't closing the whole way.Mufflers would glow cherry red and sputter like the choke was fully applied.

1 of the kohler command powered machines I've had,had a blown head gasket and acted like this also BUT it smoked pretty bad to.Gasket blew between the push rod channel and the cylinder so it was letting oil into the combustion chamber.

 

[jsoluna]

Is it possible that you may just need to check your torque on intake manifold and carburetor base? What happens to the glowing exhaust if you were to, say, apply a little bit of choke when they start glowing?

 

[diesel_nut]

carb...not ...barb. Can't edit my reply above. Time expired ?

 

[jsoluna]

Heeeheeeheee, and I thought I had missed out on a colloquial phrase that was short for 'carburetor'.