Need a kohler expert opinion?

Geo-TH,In

Well-known Member
I have a 20 hp kohler command, ch20-64519. It
runs just fine, a little on the rich side. I have
1500+ hours on it, doesn't use oil, starts good,
no issues other than running a tiny rich which
shows up on sprak plug.

Been experimenting with blending my own E17.5 to
lean engine down, which is working well. Then
someone gave me heck, saying I could change main
jets and get the job done. That is easier said
than done. I've yet to find a source to buy any
jets. No tech source to find what jet goes with
my engine. However I did find carb rebuild kits
that show an adjustable idle jet, which mine
clearly doesn't have. I can see places where the
jet was located, but blocked off. I've also
learned that Kohler has a specific model number
for engines on different applications.

1. So what makes the kohler command different
from the other kohlers?

2. I'm guessing the older kohler engines had
carbs with adjustable jets? So When did the epa
require epa approved carbs? That would give some
idea how far back I need to go to find an old
used carb. However all I can find are the newer
carbs.
Thanks,
George
why so many different model s
 
I wouldn't change any adjustment since you have over 1500 hours on the engine. If you lean the fuel setting you may cause the engine to over heat. Hal
 
Most small engine stuff has been using fixed jet carbs for quite a while now. It is unusual that you are running rich. Most of the time they run lean. Have you replaced the air filter with a more restrictive filter? Is the float level in the carb a bit high?

I have a fixed jet roto-tiller and a friend of mine has one also and they both run lean enough that we have to run the chokes half on the get tehm to run right. Both have had the fuel sytems checked out and we have found no restrictions. We are going to try higher float level next year and see what happens.
 
From my experience with them, those are all the same engines, just have a different sticker applied to the shroud. My 23 likes the next hottest plug. But I have to get a headgasket set for it. Its been pretty much parked all summer.
 
I have a Cub Cadet with a CH18S.
Inherited it from my father-in-law.
It was dropped off by someone else for him to tinker with. I rebuilt the tractor and converted it to pull my little dirt scraper/buggy.
It runs fine but on the rich side.
It has a fixed jet.
Searched all over the internet and found little information on it.
I took it apart and modified the jet so I can adjust it. Works better but still not perfect.
Would too appreciate any information.
a168844.jpg
 
All the Kohlers I ever worked on were fixed jet. Only jets that I know of. Were for special units operating at over 8000 ft.
 
George I would not mess with it too much. You have gotten 1500 hours out of it. That is pretty good for a Kohler Command engine. I buy several mowers each year that have "bad" Kohler Command motors. Most of them have around 500 hours. The most common issue is broken rings from over heating. This is usually from them running too lean.

I personally do not think much of Kohler motors anymore. I just have not gotten the life out of them that the Hondas and Kawasaki motors seem to give.

As for looking for a adjustable carb. all you really need to match is Horse power and displacement. So if yours is a CH20 that is rated at 20 HP at 3600 PRM you just need to find a carb from a motor with the same rating. The air flow and fuel requirements would be about the same. So you should be able to adjust yours to where you want it to run.
 
Different engine model numbers usually mean different applications. Usually simple and small things that make the engine different than standard, in fact I dont think they have a "standard" anymore, they all get a model number. Different shroud over the mufflet or different routing of a cable = different model number.

Many people have given you good advice and in the 5 years you have been here, you have had this hobby of playing with the Kohler engine. The only consistant thing is, you refuse to fix the engine (if there is anything wrong with it). People have even explained to you how what you are doing is not repeatable so its really a waste of time. Other people have told you how to fix it. Even more have explained how putting a different carb on will solve your problems because you can get an adjustable carb. None of this good advice was used and we are still back to the monthly "George Marsh my Kohler wont run, help me!" thread. Only to be repeated in a few weeks...

I dont believe for a second you want this engine fixed (that is, if there is anything wrong with it) nor do I believe you will take any of the advice given this week. But Im always willing to be proven wrong and as such, I have to ask, what jet did you find when you took apart the carb a few weeks ago? What jet did the local Kohler dealer sell you?
 
If it was mine I would leave well enough alone.
But as long as you realize the following may potentially wreck your engine, here are some options for you.
-Kohler part # 24755125-S is the part number for the high altitude kit for the CH20 engine.
Available at Opeengines .com
-Take a dremel tool and enlarge the bore of the carb to increase air flow.
-Drill an air passage past the carb and connect a hose with an adjustable valve on it to introduce more air into the mixture.
-Run it without the air filter.
-Loosen the carb mounting hardware to create a vacuum leak.
OR
-Have it run on a Dyno
-Hook it up to an exhaust analyzer
.
Unless you wire your governor open and do a full throttle shut down reading your plugs will only tell you what is happening part of the time when you are putting around.
If and when you put a heavy load on the engine you need to know there is enough fuel in the mixture to prevent a meltdown.
I have melted eough pistons into little marbles when racing to tell you this from experience.
 
In 1973 I bought a 1972 Super Beetle that had the
engine missing. It had low miles and an old 1600cc engine came with it. The original engine had been stolen. The owner told me his son was involved in that, but wasn't charged since he testified against the thieves.

I rebuilt the old engine with new bearings, cylinder barrels, had the valves ground, some of the exhaust valves needed replacing. Had to split the case to remove the crankshaft. One old piston had a hole in it.

After I installed the engine it seem to below on power wouldn't climb a small hill in fourth. My VW manual said not to adjust the main jet adjusting screw. I called the local VW shop about the low power and I thought the engine was getting too warm. They said to throw away the shop manual and open that main jet adjusting screw. That fixed the power and overheating.

I had bought the car to resell, but my wife wanted it so we kept it. The piston that had the hole was caused by a lean fuel mixture. Hal
 
(quoted from post at 10:34:28 09/14/14) Different engine model numbers usually mean different applications. Usually simple and small things that make the engine different than standard, in fact I dont think they have a "standard" anymore, they all get a model number. Different shroud over the mufflet or different routing of a cable = different model number.

Many people have given you good advice and in the 5 years you have been here, you have had this hobby of playing with the Kohler engine. The only consistant thing is, you refuse to fix the engine (if there is anything wrong with it). People have even explained to you how what you are doing is not repeatable so its really a waste of time. Other people have told you how to fix it. Even more have explained how putting a different carb on will solve your problems because you can get an adjustable carb. None of this good advice was used and we are still back to the monthly "George Marsh my Kohler wont run, help me!" thread. Only to be repeated in a few weeks...

I dont believe for a second you want this engine fixed (that is, if there is anything wrong with it) nor do I believe you will take any of the advice given this week. But Im always willing to be proven wrong and as such, I have to ask, what jet did you find when you took apart the carb a few weeks ago? What jet did the local Kohler dealer sell you?


rich, I think yer wrong. George has been trying to convince anyone and everyone that ethanol is good and has been trying to create his own blends to prove a point. Thing he fails to realize is people like me don't like ethanol because it's forced on us rather than having a choice. I also consider it a back door farm subsidy for corn growers. And even tough I'm now farming I don't take any subsidies.

Rick
 
It is nice two see another person who understands my issue. It's sad that others wany to critize me for asking 2 simple questions: 1. what is the difference? 2. What year did the Epa require fixed jets.

I just ignore the unhelpful critics don't know answers too my questions.

I put a want ad on craigslist. I may have found a 25 year old 20 hp kohler with a bad head. Hoping carb has adjustable jets. Guy is on a cruse, will find out when he gets back.

I want two thank those who gave positive comments. Those who posted negative comments, next time hit delete before you respond, thank you, God Bless! I'LL BE BACK WITH UPDATES!
Geroge
 
JDSeller,
I change oil and all filters often. Only operate it at about 1/2 rpm. The diy place in town says they get between 1500 and 3000 hrs before replacing engine. If you check, kohler ch20-64519 engine it's listed specifically for my terramite. The diy boys tell me it's a bear to replace the engine with a honda. They claim the kohler is quieter too. They say it's better to buy a short block than a new engine. I've seen my engine go from between $1600 and $1800. I think I will go for a new engine. I've also seen some Kohlers with EFI. Not sure if I could use one. I've seen some used terramites with a honda replacement engine. Not sure if terramite sells new T5C's with honda or kaw. I like the 17 hp kaw in my JD275 and the efi kaw in 4010 mule.

I did order a case of stens filters off ebay for $50 that you recommended for kaw. Changed oil on mower, removed the same stens filter. I noticed the kohler filter appears tp be slightly bigger OD, but the measurements from the hole to the o-ring gasket is the same as the OEM kaw filter. Plan to use the same stens filters for all my briggs and kohler motors.

I may have a line on a 25 year old 20 hp kohler carb, hoping it is adjustable. My ethanol blend is making things a little hotter, small amounts of white flakies on plug and carbon on piston is going away. So I'm using 89 octane in hopes of not getting things too hot with detionation. So far, engine has stopped dieseling, hasn't damaged fuel pump, carb or pistons.
thanks,
george
 
(quoted from post at 15:39:38 09/14/14)
(quoted from post at 10:34:28 09/14/14) Different engine model numbers usually mean different applications. Usually simple and small things that make the engine different than standard, in fact I dont think they have a "standard" anymore, they all get a model number. Different shroud over the mufflet or different routing of a cable = different model number.

Many people have given you good advice and in the 5 years you have been here, you have had this hobby of playing with the Kohler engine. The only consistant thing is, you refuse to fix the engine (if there is anything wrong with it). People have even explained to you how what you are doing is not repeatable so its really a waste of time. Other people have told you how to fix it. Even more have explained how putting a different carb on will solve your problems because you can get an adjustable carb. None of this good advice was used and we are still back to the monthly "George Marsh my Kohler wont run, help me!" thread. Only to be repeated in a few weeks...

I dont believe for a second you want this engine fixed (that is, if there is anything wrong with it) nor do I believe you will take any of the advice given this week. But Im always willing to be proven wrong and as such, I have to ask, what jet did you find when you took apart the carb a few weeks ago? What jet did the local Kohler dealer sell you?


rich, I think yer wrong. George has been trying to convince anyone and everyone that ethanol is good and has been trying to create his own blends to prove a point. Thing he fails to realize is people like me don't like ethanol because it's forced on us rather than having a choice. I also consider it a back door farm subsidy for corn growers. And even tough I'm now farming I don't take any subsidies.

Rick

Rick, I really cant argue that angle of it because I dont offhand remember Georges stance on ethanol so you could well have a point with your statement. I wont look back now but I have looked back at Georges posts all the way back to when he first joined the forum and clear back then, he has had a hobby of pretending to fix this engine. Just a couple weeks ago he was claiming to have looked all over, including Ebay for a carb. He was lying because in 3 clicks starting at Google I could find one. New ones, used ones, old but never installed ones, tons of them. He just didnt look but claimed he did. He was also told the answeres he needed, where to find parts but he has some aversion to simply fixing this engine (If it is in fact having a problem). Why he wont go to his local Kohler dealer and get a new jet is beyond me. If he dont have a local Kohler dealer, he could order online. He refuses to even state what jet he currently has in the carb. There are people reading this webpage that could likely send him a jet if he would simply open the carb and read the jet number. But without that, Im not wasting my time, postage or any of the jets in my bins on a guy that apparently is unable to even open a simple carb (insert old adage about a horse and water here). He is never going to get the help that he claims to want or need if he is unable to open a carb, in that case he can keep playing games and mixing gas, making placebo fixes that can never be repeated (if they did anything to begin with).

But like I said before, at least it keeps him out of the tavern...
 
If you really want to know the differences, just go to Kohlerengines.com and read, a lot! Far to much to retype here.

I understand your using ethanol to lean it out, but I do think your interpretation of what's going on is flawed. Alcohol of any kind in an engine will reduce, not increase temps unless other changes are made. That can be borne out just by understanding the power reduction associated with alcohol.

My Tundra is a flex fuel engine. But, mileage and power are greatly reduced. AND, the oil change interval is halved if using high percentages of methanol! At 8 qts per change, the added cost of 2500mi vs 5000 has convinced me it'll be gasoline only!
 
Well, I have no noticable loss of power. I've been reading too. Some place I read that idle speed is around 1200 and max is 3600. Because I'm not running at max rpm, is it possible car fixed jet carb isn't leaned out all the way?

Cooling the combustion was one of my objectives to stop dieseling, which it appears to have happened.

I change oil every 75 hours. Just changed the oil. Be interesting to see how long I can go before the oil looks like dirt. It only takes 2 qts so it's oil changes is no biggie.

Removing carbon was another objective, it too is happening.

In the past I was using the next step hotter plug to plug from carboning up. I went back to the oem plug and things have improved.

My last concern is winter time blend, colder more dense air. Colder air requires me to richen up my marvel carb on Jubilee by 2 full turns in winter to make power. I don't use an ethanol blend on Jubilee, but it has super white plugs just like my IH C. Both tractors are very good on gas. I use them in summer to mow. I think they use about the same fuel to mow an acre as a riding mower uses.

BTW, I noticed a gas station selling E30 fuel at the same price as E10. So where is the savings when E30 gives less mpg?

Thanks for telling me I'm on the right track. Not everyone seems to agree.
George
 

We sell tractor parts! We have the parts you need to repair your tractor - the right parts. Our low prices and years of research make us your best choice when you need parts. Shop Online Today.

Back
Top