[caserep]

I purchased my '87 444 this past spring at a consignment auction and have been working on it ever since. I have learned much from all you gentlemen on this site and this has been helpful in the rebuild process, as I am not much of a mechanic.

I now have my tractor running and am breaking in the rebuilt engine. I have about 10 hrs. on it and have change oil twice and expect to take it easy on the engine for another 5 hours. I have not run the engine over 50% throttle, with only very light mowing.

I feel the engine is running too hot. Too guage how hot, I used a stack thermometer I use on my wood burning stove. After running the engine for 15 minutes with the mower running, I turned the engine off and placed the magnetic thermometer on the engine in the area of the engine name plates. I get a reading of 125 deg. F. The hood gets too hot to hold your hand on it. The metal below the controls, in front of your feet, is warm. Everything seems hotter than it should. Is this normal for a newly rebuilt Kohler motor?

The motor has a new std. piston & rings, and rod. A friend of mine helped with these critical parts of the rebuild - he is competant in this type of work.

Do you feel I have a problem here? Should I shut her down until I figure out the problem; if there is a problem. Or will this engine cool off after it has "seated in"? Or maybe this heat normal?

Thanks in advance for any thoughts you may have. I enjoy this site a lot and look forward to learning more about the great tractors in which we all have an interest.

 

[Bart]

Usually an engine running hot is running lean, i.e. not enough fuel in the mix from the carb. You may want to first check the carb adjustments to make sure they are correct. An infiltration of air between the carb and the engine can also cause this type of problem though I don't believe it is common on Kohler engines--make sure you didn't forget a gasket between the carb and the engine.

The engines are also designed to be run at full throttle which moves more cooling air across the head so it could be that you're running it too slow.

As for heat around your legs, make sure all the engine baffles are in place as they help direct the hot air away from the rear of the tractor.

 

[Hydriv]

I wonder if you realize that the water-cooled engine in your car or truck has a thermostat that controls the flow of coolant through the engine block. Most thermostats are set to open at 190 degrees F and that's the temp your engine runs at most of the time. Air-cooled engines often run a bit hotter than that. You are not getting a true reading. There are better thermometers available and you might want to consider investing in one. One or more of our members will make some recommendations, I'm sure.

I also suggest that you learn how to READ your spark plug because that's a good way to figure out just how hot things really are inside the combustion chamber where it all happens.

http://www.ngksparkplugs.com/tech_suppo ... aqread.asp

 

[Bob MacGregor]

A few questions and comments:
Does the carb have and adjustable high speed jet?
Fixed spark timing, no breaker points?
Flywheel alternator?
Were all the cooling baffles put back in place?
Were the piston ring gaps checked prior to installing the piston?
Was the carb cleaned and settings checked?
What does the exhaust pipe interior color indicate?
Breakin oil? Non detergent 30W?
Exhaust leak towards the hood?
Bring the engine up to 3,600 RPM and adjust the high speed jet.
87 octane gas with 10% ethanol is no longer 87 but more like 84-85, try 91 or 93.
All new or freshly overhauled engines will run hotter until they settle in.
Use an IR non contact thermometer like a Raytech.
Check the spark plug condition/coloration as Hydriv has mentioned.
Find someone with a similar tractor and compare temps with a IR thermometer.
Hood will get hot, the paint on both my Ingersolls is borderline burned particularly the undersides around the engine. Each have over 2,000 hours, repowered and were used commercially for mowing and snow removal.
Mad Mackie in CT :mrgreen: :mowlawn:

 

[caserep]

Gentlemen, Thanks for taking the time to respond to my inquiry.

Hydriv, I have pulled the plug on which I have these 10 hours of break-in running. The plug looks normal compared to these photos. This was a good suggestion, as these photos are usually in black & white in a manual, these sharp color pictures were easy to compare. My plug looks good.

I realize my thermometer is not high tech, but it is consistent and gives me a frame of reference as to what the engine is doing as I make adjustments.

Bart,I believe my carb. is adjusted correctly, but not 100% certain. My friend that helped me rebuild the engine was here yesterday and we were looking at a few things. His comment concerning running lean was the engine would bog down/choke, when accelerating the engine quickly if it were too lean - this was not the case with this engine. Not sure this is a good check.

Yes, a new gasket on the carb. - don't know if there are any other issues with incoming air - none obvious. Do you feel it is OK to run this engine at close to full throttle during this break-in. I am hopeful this may be the problem - if I run at higher rpm, but just little to no load on the engine, this might be better? All the baffles are in place.

Bob MacGregor This is a K321 engine with flywheel alternator and points.
The carburetor is not original, it is a new Kohler TT245-A purchased locally and installed since I got the tractor. It was adjusted by a past Case dealer when we installed it. This carb. has the normal 3 adjustment screws.

All the baffles are properly in place. Concerning the piston ring gaps, I don't recall micing the gaps. The cylinder was in pretty good shape, we honed it and installed a standard piston and ring set. I did look at the interior of the exhaust pipe at the engine side of the pipe, all I recall is it being dark colored coating. On this last oil change, I did go to straight 30W oil. That didn't change the engine temp though.

I don't detect any exhaust leaks. New gasket on the pipe at the engine, new muffler at the other end. All seems tight.

I am using cheapest gas; are you suggesting I should be running higher octane fuel? I have never used anything other than regular gas in all the engines I have.

I will try to borrow an IR thermometer and see what I can see.

At this point, if you agree, I am going to run this at a higher rpm and see if this changes anything. Because I am not smart about most of this, I want to error on the side on caution so as not to damage this engine. Too much time and money envolved. Hopefully all is OK with this engine re-build and she will cool down with a little more run-in time.

Thanks so much for all the advice and suggestions.