20 hp kohler command horizontal shaft?

Geo-TH,In · Jan 28, 2015

I have a 20 hp kohler command horizontal shaft engine on a terramite T5C. I change oil and filter every 60-75 hours. Engine runs fine. No major issues. Was told the kohler has a tendency to blow head gaskets. So, I never turn engine off for short periods of time, let it idle.

I want to know many hours can I expect to get out of engine if I take good care of it and only run it about half speed. Anything I need to watch for?
Thanks
Geo

jeffcat · Jan 28, 2015

From what the guy at the repair shop told me. Kohler engines know as "courage" engines have the most problems. Made from like 2005 and up. Blocks crack, heads blow and don't know what else. The ones made few years back to today are supposed to have all of the cheap engine bugs worked out. CHina... Heads did not have enough bolts and the head would end up blown into the head lites. They added another bolt so the head wouldn't blow off. Engine would crack at where the cylinder and the block meet up. One fix was to lock tite the head bolts and make sure they had the correct tourqe. I had one till it cracked and replaced it with a Briggs twin V 21hp. Fantastic engine. You could always go to a real good shop and ask them to just check her over. Should take them only a few minutes.Jeffcat

W_B · Jan 28, 2015

I have a Courage twin vertical shaft on a Husqvarna mower with 540+ hours and it still purrs like a kitten, well a bit of a ragged kitten but still...

Geo-TH,In · Jan 28, 2015

Jeff and W-B, Mine is a command, roller mains, hyd lifters. 2014 and 1600 hrs. Runs great, doesn't use oil. change oil 60-75 hrs

Just wondering what the issues may be. I talked to one guy who had either dropped a valve seat or something wrong with exhause valve on his command.

So I wondering if running engine full throttle and getting it hot may cause exhause valve issue.

jeffcat · Jan 28, 2015

Ok ..now that you added a little more information. No you have a good engine but if it is OHV then what I do.."this is me", I use a synthetic blend oil. I use 5 w or 10w30 all summer long in all of my lawn stuff. You may want higher like 10w40 . That blend stuff will not screw around with your seals and the sythetic will not burn in your engine. This is one of the things that will make all of that carbon in your engine. I can hear all of the ney sayers reving up in the wings!!! All I can tell you is the OHV engines have more heat out there where the rockers and rods are and my little Troy Pony has run fantastic for going on seven years now. Two years ago I pilled the valve cover to check the valve clearance. It looked as if the engine had been run for maybe ten minutes! NOT A SINGLE spot of crud anywhere! This synthetic deal has gone round and round a couple of times but I am very happy with it. It DOES flow a bit easier so check your dip stick more often cause you may have a little consmption! Just check it.

T.R.K. · Jan 28, 2015

I work on a lot of those Kohler Command engines in commercial zero turn mowers. I have seen one go 2500 hrs. when it needed rings. It is rumored that there is one out there still running with well over over 4,000 hours on it, but I bet it uses lots of oil.

Several factors come into play to make one run that long. Regular service is one factor. Clean air filters, clean fuel and clean oil count for a lot. And Kohler does not recommend blowing out air filters, tamping the dust out of air filters, washing air filters or anything other than replacing the air filter at regular intervals. (I'm harping on this because we had a Briggs engine in the shop today with 700 hours and worn out and leakng oil because the customer never changed the air filter.)

All the above said, your particular Command engine is probably not going to give you the above stated kind of life. You say you are running it at 1/2 throttle, so it is not cooling itself efficiently and also if that Terramite is hydrostatic powered, you are lugging the engine too. Most hydrostatic equipment is really designed to run at wide open throttle to operate most efficiently.

Geo-TH,In · Jan 29, 2015

Yes, the Terramite is hydrostatic powered. Never seem to be lugging the engine. I can always adjust the controls to slow it down, rarely stall the engine. If I run wide open, the backhoe controls are very snappy, too much hyd pressure. Some times I may run at 2/3. Rarely run 100%. The engine seems to play with hyd pump.

I will be happy to get another 1600 hours, even happier to get 4000. Will change oil, filters sooner than kolhler recommends. I change it when I notice oil turning dark and it will tend to use a drop of oil at that point too. Time to change which is 60-75 hrs. Been thinking of using synthetic oil. Any opinions on that?

The engine will cost about $2k, shipping and tax, so if I get 4000 hrs that's $.50/hr.

ztrmower · Jan 29, 2015

running it half speed under load is the worst thing you can do for it. they are design to be full throttle and run the coolest then when under load. idling engine down in air cooled engine makes them run hotter. put that baby at full throttle and leave it there. done my stuff that way for years and have yet been into one. ol in

OldBuzzard · Jan 29, 2015

Like a couple of other guys have said, run that rascal at WOT when you are working it. I'll double dang guarantee you that your owners manual will say to use WOT.

If the hoe is to 'snappy' for you, consider a flow limiter to cure that.

Geo-TH,In · Jan 29, 2015

I have an exhaust temp guage that I'm going to install on engine head and see if I can measure actual temps at 1/2 and full speed.

If the exhaust temp guage doesn't work, I'll buy an engine temp guage.

As for running an air cooled wide open, I ran my old air cooled VW wide open. It melted the exhaust valve in half. All Valve were just put in engine about 5k before, head job. So I'm not totally convinced wide open is that good of an idea.

Also worked on an old 3.5 briggs someone ran wide open. It dropped the exhause valve seat. Another hammered the valve seat in to block.

Will report back on what I find by measuring actual temps. Thanks guys.

JT · Feb 1, 2015

I will add my 2 cents for what it is worth. A Kohler command needs to run at manufacturers recommended WOT 90% of the time, as the air off the flywheel fan is what moves air across the fins on the engine to removed the heat out of the engine, if you do not run any air cooled engine at WOT throttle at least 85% of the time, the engine WILL have catastrophic. premature failure from over heating. Running at 1/2 throttle will blow a head gasket from overheating. What happens to your car or truck if you cover half the radiator so the engine only gets half the cooling ability?
As for synthetic oil, if you are using a good quality 10W30 oil, designed to run at the temperature an air cooled engine runs at, is not really needed.
Last but not least, when you shut the engine off, always shut off at 1/2 throttle or above, as they have a high speed shut down solenoid in the carb that shuts off the fuel so it will not backfire, shutting off at idle can cause a backfire that can blow a head gasket or blow out a 200.00 muffler.
Other then that, a Command is a pretty bullet proof engine with proper care and use.

Geo-TH,In · Feb 1, 2015

jt,
Thanks for your input. Before I figured out I had an ignition module problem, the module wouldn't stop making a spark when shorted out. I removed the kill wire to both coils and within a few seconds the solenoid in carb killed the engine after it ran out of gas. However, it would take more cranking to start engine once carb was out of gas.

I also discovered that making an E20 blend, cooled the engine, eliminating dieseling. I will try running engine faster before shutting it off. Only seem to diesel during the hot summer. I never had a backfire problem, just dieseling.

Geo-TH,In · Feb 2, 2015

jeff,
you are right about the heads get very hot. I purchased an IR laser pointer thermometer. To my surprise the head is extremely hot. Block cooler and crankcase about 130.

Next oil change will be 10w30 full synthetic.

I use 5w30 full synthetic in new generators and 10w30 in jubilee. No problem. Good seals and gaskets don't care about synthetic. If seals are old and dirty, the synthetic may clean the dirt and perhaps cause leaks.

Bob - MI · Feb 8, 2015

I have about 350hrs on my 20hp Courage horizontal in a Cub Cadet 2518 and I have absolutely no complaints.

After break in I followed the manual recommendation and put 50 hours on the clock and then switched to 10W-30 Mobil 1 Extended Range full synthetic oil. I change it about every 50 hours or so along with a fresh air filter cartridge and a new pre-filter. I have had zero issue with this engine and have been really pleased.

When I shut it down from running hard I let it drop to a fast idle for a bit and then run the throttle up while cutting the ignition. This lets the engine rev up so when the carb solenoid closes it's got enough momentum to clear the cylinders without backfire.

20 hp kohler command horizontal shaft?

Geo-TH,In

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W_B

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ztrmower

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