I have a lawn mower with a Kohler ch23s engine that I am trying to get running correctly & was wondering if anyone is familiar with them.
A bit of background I got the mower with low hours but not running. A fuel pump & tune up got the motor running but it burned oil badly on the left cylinder. Internet research showed head gaskets were a common issue so during the winter I pulled the cylinder head. I found someone had apparently had the head off before, as the dowles were crushed. I replaced the head gasket & both dowles on that cylinder, it did not make much difference in running. The mower will stall out in tall grass & burns about half a quat an hour. I removed the plugs & found the left cylinder plug was full of white carbon. So it looks like my issue is still with that cylinder.
I am between rebuild or replace at this time, rebuild kits are available & not too expensive but I would probably want to limp it through this year to avoid down time. It looks like the crank height is different than the hammer store predator so while that engine is cheap it would require fab work. Kohler has changed their naming system but it looks like the newer engines use the same basic block. There is a site that lists a 25 horse ch740 plug and play upgrade but that is the most expensive option by far.
Any advice on limping it through until winter without spending big money on oil? The white carbon on the plugs could be jamming a ring, sea foam in the oil did not have much effect, maybe an additive in the cylinder to soak followed by an oil change. Or should I suck it up & get the plug & play engine?
Im a big kohler command fan. I was an authorized kohler tech. I also heard they were running about 2 years out on being able to fill engine orders.
did you run a compression test?
Compression test is needed. It sounds like the rings may be worn out.
I still need to check compression, I really should have done that when I had the plugs out. Does kohler recommend a warm or cold compression test? I'm hoping the head not sealing allowed carbon to build up to the point of causing the rings to stick & if I can free them up the issue will be solved. It may have lived a rough life & is due for a rebuild. I am worried about what else I may find when tearing it down though.
what weight oil are you running? I'm seeing that Kohler recommends straight 30 weight or 20W50.
They have a number of different weights, the kohler service kit I bought came with 10w40 semi synthetic. I have not run anything higher than that yet as I have been trying to stick to locally available high zinc small engine oil.
I ordered some acdelco top end cleaner to try, I have had good luck with that cleaning intake carbon. I will take a before compression test, soak it for a few days, than start & run for some time & do a second compression test.
I'm still hopeful on freeing a stuck ring as the hour meter only show 374, but previous history may have damaged something.
Our kohler popped at 450 hours. And by popped the rings were so wore out that it couldn't restart warm and any grass more than 1/2" tall would pull the engine down 500rpm.
replaced ours with a 25hp Briggs. Literally a drop on and go. Make sure your crankndiameter and length is correct. The bolt pattern will be the same.
The Kohler command is a commercial quality engine. All the "courage" and newer motors are disposable and had a bunch of issues when new. I ONLY mess with the Command series.
the command series always asked for 10w-30. It has hydraulic lifters.
its a horizontal motor. It has a oil breather running into the carb. There is a spongy filter and a flappy metal leaf reed valve in there under the cap to act as a 1 way valve. It may be worth peeking in there and see if there is any abnormalities.
Im not vouching for this video, but it shows the process i mentioned.
https://m.youtube.com/watch?v=Ba7clojov14
I got around to working on this more this weekend. On a cold engine my compression was 60 psi on the left cylinder & 90 psi on the right. I used the top end cleaner for a few cycles on both cylinders & ran some through the carb. After that on a warm engine the compression is 140 psi on both cylinders, this is on an older craftsman compression tester that has always read about 20% low.
So I'm hoping I'm making progress on this engine. I do see some signs of an exhaust leak on the left head so I need to I check the gaskets & torque on the exhaust manifold. I have the left cylinder soaking again, after a run to tractor supply for an oil change hopefully my oil consumption will improve.
Update to this after a long time. We purchased additional acreage so have been working the mower harder. The oil consumption suddenly skyrocketed to close to a liter an hour. I made the decision to install the more expensive ch740 direct replacement engine from a company called repower specialist. It came with a crank adapter & wiring harness to make it plug & play for the most part, so it was a 1 day swap. Oil consumption is gone, heat is reduced but fuel consumption is up making me think a partiality clogged carb may have damaged a piston. When I get time I plan on pulling the old engine apart to see what I can find, it may make a fun gokart project for my daughter when she gets older
