How hot is too hot?

[goldeagle 31]

With the ongoing issues on my K341 engine I have been concerned it is overheating. Finally got around to taking a temp reading (using one of those non-contact IR sensors) and after running the tractor for 3 or 4 minutes (with PTO on) the hottest part of the engine was the exahust/muffler (if that's the right term) which is hitting about 600 Degrees C (1112 Deg. F). Is that an acceptable temperature or does it suggest there is an issue with overheating?

 

Whether or not i makes any difference but the exhaust/muffler has a crack in it which appeared recently and fairly certain it has something to do with the heat, but could be wrong

[oliver2-44 9,758]

I’m not aware of any published temperatures for small engines. But 1112F on that muffler is HOT in my opinion. Sometimes running the engine with the carb adjusted to lean can cause an extra hot exhaust. Go to the Kohler manual and adjust the carb the way it describes.  

[peter lena 8,634]

@goldeagle would personally look over the engine related cooling intake / discharge areas , might even  pull off a few engine cooling tins  , mice / related love to find a warm spot to build a nest , collectively add up to issues . possible muffler  inner flange , noisy  ? snoop around , a grass / litter  area , might show you the way . pete

[ri702bill 8,327]

8 hours ago, oliver2-44 said:

I’m not aware of any published temperatures for small engines. But 1112F on that muffler is HOT in my opinion. Sometimes running the engine with the carb adjusted to lean can cause an extra hot exhaust. Go to the Kohler manual and adjust the carb the way it describes.  

There have been posts here in the past that show the muffler inlet (tube, not pipe) glowing red at night. Richening up the mix helps. Too lean can cause exhaust valve damage. As can having the exhaust valve clearance to the tappet too tight - the valve cannot shed the heat to the seat... A chunk of unburned carbon caught on the seat under the valve will do that too.

Ever had the head off to de-carbon it per the Kohler schedule????

Edited July 5 by ri702bill

[goldeagle 31]

1 hour ago, ri702bill said:

There have been posts here in the past that show the muffler inlet (tube, not pipe) glowing red at night. Richening up the mix helps. Too lean can cause ehhaust valve damage. As can having the exhaust valve clearance to the tappet too tight - the valve cannot shed the heat to the seat... A chunk of unburned carbon caught on the seat under the valve will do that too.

Ever had the head off to de-carbon it per the Kohler schedule????

 

I had the head off a while back when I had to replace the exhaust valve (previous one bent after screw came lose and ended up in the head), so it is a new valve, and checked tappet clearance at the time. Will spend some time working on the card adjustments and see if that helps. Muffler has got a big old crack that appeard recently which I will have to repair

[8ntruck 7,016]

That crack looks like it started in an area of rust.  The rust thinned the metal and operational vibration probably opened the crack.  Exhaust heat helps accelerate the rust formation.

[oliver2-44 9,758]

Looks like someone has done a braze repair around part of that in the past. brass and steel don't mix, so you may have to continue using braze for at leas part of the repair.  The rust on the inside of that will make it a challenging repair no matter what type weld you use.  if you have access to metal forming equipment fashioning a large cone shaped washer to go from the pipe (over the crack) maybe all the way to the outer crimp area.