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Onan Engine

928gene928

Cast Iron
Joined
Sep 13, 2005
Location
Joliet, Illinois
I have an Onan Model# CK-MS, 10.1 HP motor that was attached to an air compressor prior to conversion to an AC motor. My questions is that I now have another application for the gas engine, but no information or manual. Does anyone have any information about this series of Onan engine? I have had it for a long time, so I suspect it is an old model. Thanks for your help.
 
JR Iowa

JR,
Thanks for the reply. I did a quick Google search, and did not find anything helpful. I was hoping to get some general information, like spark plug type, type and quantity of motor oil, etc. I will take a look at Cummins. Thanks!
 
I have a manual for Onan CCK & CCKA engines. The MS just means electric start. I don't know how it relates to CK engines, but if you can't find the information anywhere else, let me know.

Bill

Edit- I got the forklift that uses the engine used almost 30 years ago and it was an older model then, so yours is probably older than that.
 
I would say his 10hp engine is single cylinder and the CCK series as far as I know were all twins. I also have manuals for those as they were what came on the Allis Chalmers 720 and Simplicity 9020 tractors. We found out before Cummins took over Onan that Onan no longer had any interest in support for their older lines of equipment and what parts they did still have they jacked the prices up so you would quit working on the things.

Best thing we ever did for our 720 Allis is rid it of the Onan engine and installed a 24hp Honda in its place. Much more reliable, runs cooler, uses almost half the fuel as the 20hp Onan, way more power, and in almost 9 years of use since its repower NOT 1 CENT in repair parts.

My thought is if I was putting an engine on some piece of equipment the Onan's would be right near the bottom of the list of acceptable.

tim
 
Yes, my engine is a twin, in a 2000 pound capacity NAMCO standup forklift. The engine only drives a hydraulic pump and all the functions are controlled by valves. The wheels are powered by hydraulic motors. It doesn't get heavy use, just for moving things around the shop. I had to do some work on it when I got it, but since then the only service has been on the propane carburetor. The engine never gives trouble, but I probably have not put more than a few hundred hours on it in all this time.

Bill
 
The smokstak site has a Onan board and some hard core Onan people with any and all info you could ever want.
 
CK specs.

C.I. 2 cylinder
C.R. 5.5:1
Oil Cap. 3.5 with out filter add .5 qt for filter
Spark plug gap .025 for gasoline engine
Point gap .020 for gasoline engine
Ignition timing 19* for gasoline engine
Valve Lash intake-.006 exhaust.015 engine cold

Spark plug brand is up to owner.I bought mine at AAP.
 
CK Specs.

Ray,
Again thanks very much for taking the time to find the info for me! My engine has Champion J11J plugs, do your specs recomend any particular heat range or plug type? My engine is not equipped with a oil filter. There are some markings on the side of the fan guard which also say 2 quart oil capacity?
 
The spark plug's heat range depends on a lot of small things.I bought mid range plugs for my CCK,CCKA and CCKB based mainly on the age and condtion of the engines after rebuild.As far as oil capacity,it depends on which crankcase the original engine came with.Since yours is two quarts it's probably based on it's original use(driver for AC pump).Onan crankcases are interchangable so you can increase the capacity by simply changing the crankcase.All of mine have the welder/generator crankcase.There's really no advantage other than the extra oil.Changing the crankcase also alters the cases bolt pattern for bolting the engine down.

10 or so years ago I was lucky enough to come across a slew of NOS surplus Onan parts.I've been hoarding them ever since.Maybe nows the time to help others out with what I have.Inquiring minds can ask by PM.
 
Onan CK

We have 2 Onan CK-S/A8 engines here at the school that my students are trying to rebuild. They are air cooled 10hp, we did finally find a parts catalog but could really use a repair manual if anyone has one. The other obvious problem we are having is finding the kits for rebuilding them. If anyone has any ideas we would really appreciate the help.
 
dustbomb37,

I'll look and see if I can help with a repair manual.For the most part Onan manuals that cover CK,CCK,CCKA,etc. are general repair manuals that would cover your engine but not the specs.

What do you need specifically in the students rebuild project as far as parts?I might be able to help in new or used.Please email me at [email protected].

Many thanks,
Ray French
 
Per earlier comments, A friend of mine has an Onan two cyl 3 phase generator set, out of a truck refrigerator. It is from 1958. it was overhauled about 25 years ago, and he was thinking it might need another, it gets pretty hard use.

He called up the local distributor just a couple weeks ago, and they told hm they had or could get just about "everything but the block" for that engine. Apparently Cummins has not decided to scrap out the old parts yet.... if they ever do.
 
I wonder if he could get oversized pistons? (A pretty important part for a rebuild).
About 10 years ago I rebuilt a 16HP Onan in a 1976 Craftsman Lawn Tractor.
No OS pistons available, but the recommended practice was to bore the block .125 oversize (I think that was the number) and use standard size 18HP pistons, which I did with success.
At that time, parts from Cummins Northeast were quite expensive. Fuel pump kit $65, Carb rebuild kit $85, Float $35......

But I did call and talked to an engineer at Cummins to verify the cast-in sleeves and block could go that much larger. He said yes, and also said the cams were different between the 16 and 18hp engines.


dk
 








 
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