Lawn Care Forum banner

Kohler CH20 pulls down under load

13894 Views 18 Replies 8 Participants Last post by  kernopelli
I just bought a JD F680 w/54" deck and will be picking it up in a few days. Owner reports mower has a new short block, PTO clutch and carb installed by dealer w/ 2 hrs on them and it runs/drives fine but revs pull down when the clutch is engaged and you start to mow. The clutch and carb were installed separately by the dealer as attempts to cure the issue and eventually the previous owner and the dealer grew pretty aggravated with each other and threw up their hands and gave up. JD owner became a Dixie Chopper owner and I became a JD owner.

I am thinking governor but can't imagine that the dealer didn't try adjusting it 1st thing but the old owner doesn't think so. I would also guess carb but that has hopefully been addressed. Since it was a short block, it am wondering if the valves were reinstalled a little tight and maybe it's down on compression? I don't know yet if this engine has the smart spark feature but am wondering if this could be an issue since I read about a similar problem in an old forum?

I'd like to hit the ground running as soon as I get the mower home and have a list of all possibilities to check. I really don't expect this to be a major issue since the heads were supposedly checked out and OK, the engine has a new factory short block and carb and the work was done by a (questionable???) dealer but do need some help on possible ideas that would cause this symptom...any ideas out there?
1 - 4 of 19 Posts
As mentioned,

Check both coils by removing each plug wire one at a time at idle (use rubber handled pliers) and see if the engine stalls completely, If so the coil/plug on the opposing side is not functioning.

Check governor adjustment.

Check high speed RPM's, Can be set at 3750 no load.

Check ALL deck spindles and any idler pulleys for binding.

That should be enough to get you started....
See less See more
Is it safe for me to run this engine at 3600-3700 rpms?
Do you think for a minute I would have typed 3750 above if it would cause issues ?

Most commercial Z's come from the factory set at 3700-3750 no load....
is the JD spec engine significantly different than the other CH 20's and won't tolerate the revs and if not, am I going to damage something like a hyd. pump or something else by spinning it faster than Deere intended?
No difference in engine build, There are only a couple companies that build hydro pumps for all the OEM's so Deere uses one of these. So if a pump works fine on one unit at 3750 it will work fine on another brand unit at 3750.

You should be fine at that RPM.....

please don't take offense by this question
None taken..... Thumbs Up
Two words, Tiny Tach;

It's also a hour meter so you can keep track of maintenance, This is the same one we use on all our rental equipment. If you mount it on the machine do so out of direct sun light.
1 - 4 of 19 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.