Kohler CH 20 Running Super Rich ?

GTSRider · Aug 18, 2011

Here's a quick background of what I 've done to this Keihin carb on a
CH20 engine with 550 hrs.
New fuel filter
New Fuel pump
New carb rebuild kit with new O-rings and gaskets
New Air Filter assembly
New Spark plugs
Engine running Super Rich....only thing I can think of is float level is off
Anyone know proper Float level adjustment ?
Seems like way too much fuel in bowl...about 1/2' from top.
Tempted to put on new carb.... but I must do a compression check first...
Are vales in these engines hydraulic ?
If not I think the valves may be tight....
Just can't believe the problems with this thing.....last season ran 100+ hrs.
incident free....this year daily problems.
I also need to install a new crank seal...tractor is one greasy mess.
Thanks for reading,
Pete

OldMachinist · Aug 18, 2011

Here's the Keihin float level adjustment info from the Kohler service manual.

I uploaded the complete manual here.
Command_18-26hp_horz_oper.pdf

GTSRider · Aug 18, 2011

Thanks...interesting what they say about replacing float, if spec is off...
I've never heard of such a thing.... what say you ?
Pete

OldMachinist · Aug 18, 2011

I've never seen that before ether. It can't hurt to try.

GTSRider · Aug 18, 2011

Compression in right cylinder is around 160.... 180 lbs. left, according to
Snap On compression gauge...so I think engine internals are ok.....
maybe a little weak on right...but good enough.
So now I am shopping for a new Keihin carb.
I've done everything to this one and engine barely runs other than full
throttle..... and runs like a soot machine with black smoke out
exhaust pipe.

GTSRider · Aug 18, 2011

Now that I have decided on a new carb..... my engine is a 2003 model...
but my question is... is there a better more updated carb to go with....
rather than put on the same carb that was on there ?
Pete

OldMachinist · Aug 18, 2011

You are sure that the choke is opening fully after you put it back together the last time.

GTSRider · Aug 18, 2011

Positive..... I 'm so careful at this point... I clean air filter once a week....
and it only has about 15 hrs. on it from new.
Funny thing is ... engine ran lean from around June to end of July....
and would not run without 1/3rd choke.
then it started running rich....super rich !
I've cleaned carb so many times I lost count.... and installed a rebuild kit....
I'm finally at the end with this carb and will order a new one.... but it better
not have the same results with the new carb.... I mean could it be ignition ?
I don't think so , because it runs fairly strong at full throttle although not clean.
I was mowing a very thick lawn this morning, so thick it was caking out
" bricks " ,and engine never lost rpm.... and compression check says cylinders are ok.... so by process of elimination.... it must be carb.... sunk $120
in new solenoid... and $50 in rebuild kit...**** ...that's most of a new carb right there !

OldMachinist · Aug 18, 2011

There are several carbs on Ebay for the CH20. This one is a good deal.
Kohler Carburetor Part 24 853 34 s | eBay

GTSRider · Aug 18, 2011

Hey thanks Man !
That is a great price... I think I am going to go with it.

GTSRider · Aug 20, 2011

Ordered new carb thanks to Old Machinest.... and from pictures ... it has a
linkage assembly on right side opposite choke and cable connections....
could this carb have a pump on it ?
Pete

OldMachinist · Aug 20, 2011

Yes it looks like it has a accelerator pump.

GTSRider · Aug 21, 2011

Ok.... I know why motorcycles need an accelerator pump....
but a garden tractor ?

GTSRider · Aug 25, 2011

Ok...latest up-dates....
yesterday, I installed new crank seal to stop oily mess all over front of engine and mower deck....took like 3 hr.s to do job , and 2 hrs. to clean messy greasy tractor. Engine is bone dry now....but still runs like crap from super rich
mixture.
Today I installed new Keihin carb ,with fuel accelerator pump, and bigger throat from ebay.... (thanks to Old Machinest )
After 10 -15 minutes or so of trying to get engine to run for more than
2- 3 seconds, I gave up in discusst and went to have a beer with my buddy and get his input. He said I got a bad carb off ebay.
Left there, in a state of depression... and went home , and cranked engine...
ran for like 4 seconds with choke on. Kept playing with it , and got it to run for about 5 seconds tops ..... gave up again , and decided to shower up, and call it quits. Picked up any tools , and put them away.
As I was walking away from tractor , I , for some reason, I decided to give it one more try, I forgot that I had thrown a t-shirt over the carb for the night ,
to keep any debris out of it. I turned starter over , and engine ran
fine for about a minute.. then stalled...when I remembered t-shirt.
Pulled t-shirt off of top of carb , and tried again...this time engine purred like a new re-built engine. So what happened ?
I have a theory that bone dry carb, took that long to fill from fuel pump...BTW fuel pump is new with about 25 hr.s on it now....
Or was there a piece of dust in carb that broke free ?
Don't know , but fine now...of course real test is a 3 hr. mowing
This problem has been going on since May, and has been making me crazy.
First post will tell you what I replaced.
Thanks to Old Machinest and others for your input.
Pete

GTSRider · Aug 25, 2011

One last carb question... there is a very fine spring on the throttle linkage rod,
to this Kohler CH 20..... it broke when removing it.
Dealer did not have one in stock ...so ordered a new one.
Now it seems it is unnecessary, as it seems to run fine without it.
I already ordered spring and will get new one next week.... but what is this very fine small spring for ? I can't figure out what it's purpose is ?

OldMachinist · Aug 25, 2011

The spring is just to keep pressure on the governor linkage. Without it the rpm's may surge up and down some.

GTSRider · Aug 25, 2011

Ok..thanks... I have it coming in on order and will use it.
I have 2 brand new Kohler crank seals....some how ordered wrong part #
They are new in Kolher bag. If you want them I will send them to you...no use to me.
Part # 24 032 19-S about 1.25 inch inner diameter, so must be for a
smaller engine.
Pete