Kohler CH18 won't rev up.

[JamesC-120 204]

A few weeks ago I put a Kohler CH18(by the way it was used) in my Raider 12 and since the first time I started it, it just won't rev up. When you put the throttle up it just wants to die but occasionally it will rev up fine. If you move the throttle up and down quickly it will the eventually rev up. I have already cleaned ever nook and cranny in the carb many times, I replaced the spark plugs, I put new head gaskets in, I put new push rods in and still I have no luck, I set the float height. I don't know what to do next? Any help would be greatly appreciated. 

 

Thanks

Edited December 25, 2015 by JamesC-120

[Brian01 481]

Possibly bad govenor ?

[shallowwatersailor 3,213]

Here is the service manual. Maybe the linkage is binding. Hope it helps.

 

http://www.kohlerengines.com/onlinecatalog/pdf/sm_24_690_06.pdf

Edited December 25, 2015 by shallowwatersailor

[JamesC-120 204]

I have already read everything in the manual related to this issue but in a day or two I will adjust the governor back to stock and see if that helps. 

[prondzy 3,873]

James sounds like you are on the right track checking the things you have checked. I am not familiar with the CH series motors. Im a k series fan. Break it down simply: air, fuel, spark. Try one thing at a time if it doesn't correct the issue set it back and try something else. 

 

Fuel: Cleaning the carb sounds like it hasn't worked have you made adjustments on the high/low speed needles? 

You have cleaned it have you used a new carb kit or gaskets?

Is it gravity feed or a mechanical fuel pump?

 

 

Air: you have more than likely been using a clean air filter, have you checked for  vaccum leaks at  gaskets and mating surfaces? Get the engine running and spray around intake gaskets, head gaskets and any other areas trying to avoid the air filter, listen for idle changes it should smooth out or pick up slightly if there is a leak.

 

Spark: I am not sure if this is a magneto engine or a points engine but I would consider checking spark not just having spark but is the coil strong enough using a spark tester. timing with points if they are used. 

 

Hope this helps.

 

 

[JamesC-120 204]

I just messed with it for awhile and solved 95% of my problems. The governor was adjusted wrong and it was causing most of the problems but I also increased the idle and adjusted the idle fuel mixture and it seems to be running quite well for now. I think the high speed needle could use adjustment but this is one of those dumb new engines that you cannot adjust anything accept the low speed fuel needle. It just has a set high speed fuel, there is no adjustment at all.  

[boovuc 1,090]

Make sure you didn't make the fuel mix to lean when you adjusted it. It will run way too hot if it's too lean. They run better but overall, it can cause some real issues with over-heating.

[JamesC-120 204]

Well I richened it up so that should not be a problem. 

 

Thanks

[boovuc 1,090]

Glad to hear that James. I suspected the governor was playing some guilt in the issue you were having. I have the same things happen to the Kohler KT and magnum series engines. Three motors. Three owners saying they are crap. Three governors that were really messed up.

On one of those motors, (an 18 magnum), I had it running real lean until I got the gov adjusted properly but failed to re-adjust the carb fuel mix right away. The exhaust and muffler were extremely hot after just a 300 foot drive down and back on my driveway. If I would have mowed with it or ran it much longer, no doubt I would have damaged that motor.

Happy to hear you have your issues taken care of. Glad it wasn't an internal issue with the gov assembly.

[JamesC-120 204]

Well it seems to be working great, I used it for snow blowing 4" of snow yesterday and it worked well. We are expected another 8-10" on Monday night. This v-twin was a huge up grade from that 12 horse Tecumseh. You can snow blow in 3rd gear high range and the engine doesn't even bog at all. We will have to see how it handles the deep snow. 

 

Thanks