15HP Command CV426 Won't Start

Joined
Jul 2, 2019
Threads
4
Messages
23
I have a Cub Cadet model 1515 lawn tractor with a Kohler 15HP Command CV426. I can't get the tractor to start. It wants too, when cranking the engine you hear it starting to lift away off the starter but when you let off the starter it dies.

I have fuel and spark. Here is what I tried:

- Confirmed spark by pulling the spark plug and cranking engine by holding the plug to the block. I can see consistent spark.
- Verified fuel pump is working as I had a full bowl of fuel in the carburetor.
- Verified fuel shutoff solenoid was working by connecting it to 9V battery.
- Cleaned carburetor.
- Replaced spark plug. Gapped to .040" per service manual.
- Replaced ignition module
- Replaced stator regulator
- Replaced carburetor with cheap amazon one

I have noticed it back fires out of carburetor and its way more pronounced after I put the cheap Chinese carb on.

My neighbor owned this tractor since new but gave up on it last summer and gave it to me. He had trouble getting it to start. I just put a new starter and battery on it and it fired right up. Then changed the oil, air filter, fuel filter, fuel line, and spark plug once I knew it would work. Its worked fine all summer for me until now. Any ideas? Thanks!
 

Scrubcadet10

Lawn Addict
Joined
Sep 24, 2017
Threads
99
Messages
1,518
You need fuel,spark (at The correct time), and compression.
Have you checked the flywheel key?
 
Joined
Jul 2, 2019
Threads
4
Messages
23
You need fuel,spark (at The correct time), and compression.
Have you checked the flywheel key?
Good idea. I check that again. I pulled the flywheel off once this summer and the key was fine then. I pulled it to clean the cooling fins since it was losing power on 90F days this summer when it got hot. Cleaning the engine fixed this issue. Ill look at this tomorrow. Thanks
 

Scrubcadet10

Lawn Addict
Joined
Sep 24, 2017
Threads
99
Messages
1,518
I wonder if you have good compression?
Have you tried spraying starter fluid or carb cleaner in it and seeing if it starts?
 
Joined
Jul 2, 2019
Threads
4
Messages
23
Yes, I have sprayed starter fluid into the carb and it just helps towards flooding it. I suppose I could rent some gauges from Autozone and see if its low on compression. Do you know the compression spec for this motor? I may reclean the carb too.
 

Scrubcadet10

Lawn Addict
Joined
Sep 24, 2017
Threads
99
Messages
1,518
Probably between 140 and 160 psi.
But since this engine has an Automatic compression release for easier starting it will be hard to get an accurate reading.
You should probably get at least 75 PSI with a auto compression release




And one more thing, you do have the correct oil amount in it,right?
 
Joined
Jul 2, 2019
Threads
4
Messages
23
Probably between 140 and 160 psi.
But since this engine has an Automatic compression release for easier starting it will be hard to get an accurate reading.
You should probably get at least 75 PSI with a auto compression release




And one more thing, you do have the correct oil amount in it,right?

I tested it and got 40psi. I had the carb off though. But I didnt think that would matter since your suppose to open the throttle wide open. Im going to rent a different compression tool to confirm I didnt get a piece of junk from autozone. If so then I will debate if I feel like tearing it down for a rebuild if there are rebuild kits for this engine.
 
Joined
Jul 2, 2019
Threads
4
Messages
23
Sorry, forgot to answer that. Yes. The oil level was perfect and it didnt look like fuel is getting in it past the rings.
 
Top