Kohler courage 20 (sv600) cranks but won't start and backfires.....

DaSpudro · Aug 18, 2015

Hello all,

I joined the group to see if I could tap into the knowledge base and see if anyone had an idea what could resolve my current dilema. I looked back about 12 pages or so in the history and didn't see a problem exactly like mine so I figured I'd post about it.

Basically the short of it is my mower (Cub Cadet LT1045), ran out of gas last season and stopped running. Not thinking any thing of it I put gas in it and it wouldn't start or crank. Since it was the end of the season i said forget it i'll deal with it next season and pushed it into storage were it sat until this season. When I came out to investigate I discovered it wouldn't crank because I blew a fuze, I replaced it and then discovered my starter relay was bad, replaced that then found the starter to be bad.... You see where this is going. So once I finally got the motor to where it would crank I found it wouldn't fire over no matter how much I tried, not even on starter fluid. I have rebuilt the carburetor, cleaned it with polish and carb cleaner, blow all passages air ways etc with compressed air (all blows freely), polished the needle and seat, cleaned fuel shut off solenoid (you can hear it pop or snap when the 12v is hit or taken away from. It), tested the fuel pump, I have spark when the plug is removed, new plug, plug is gapped to .030, valve lash is set to .005 for intake and .007 for exhaust, i just replaced the woodruff key on my flywheel, new starter, new regulator/relay, new battery, new pto switch and relay, new fuel lines, new fuel filter, fresh gas, new oil filter and oil, new air filter and sponge.

The problem is that the motor will not fire. If I play with the choke and throttle it will backfire, or fire once then torque the whole lawn mower and stop immediatly. The choke control and throttle control does control the butterfly's on the carb so the linkage is good. Motor will also bind like the valves are out of alignment even though they are in spec. I can live with the rough starts but I'm at a loss for why it won't even start/fire.

Any one have any ideas? My grass is currently about 3-4 feet tall And I really need to get it takes back again.

Thanks,
DaSpudro

coinman66 · Aug 18, 2015

DaSpudro said:
Hello all,

I joined the group to see if I could tap into the knowledge base and see if anyone had an idea what could resolve my current dilema. I looked back about 12 pages or so in the history and didn't see a problem exactly like mine so I figured I'd post about it.

Basically the short of it is my mower (Cub Cadet LT1045), ran out of gas last season and stopped running. Not thinking any thing of it I put gas in it and it wouldn't start or crank. Since it was the end of the season i said forget it i'll deal with it next season and pushed it into storage were it sat until this season. When I came out to investigate I discovered it wouldn't crank because I blew a fuze, I replaced it and then discovered my starter relay was bad, replaced that then found the starter to be bad.... You see where this is going. So once I finally got the motor to where it would crank I found it wouldn't fire over no matter how much I tried, not even on starter fluid. I have rebuilt the carburetor, cleaned it with polish and carb cleaner, blow all passages air ways etc with compressed air (all blows freely), polished the needle and seat, cleaned fuel shut off solenoid (you can hear it pop or snap when the 12v is hit or taken away from. It), tested the fuel pump, I have spark when the plug is removed, new plug, plug is gapped to .030, valve lash is set to .005 for intake and .007 for exhaust, i just replaced the woodruff key on my flywheel, new starter, new regulator/relay, new battery, new pto switch and relay, new fuel lines, new fuel filter, fresh gas, new oil filter and oil, new air filter and sponge.

The problem is that the motor will not fire. If I play with the choke and throttle it will backfire, or fire once then torque the whole lawn mower and stop immediatly. The choke control and throttle control does control the butterfly's on the carb so the linkage is good. Motor will also bind like the valves are out of alignment even though they are in spec. I can live with the rough starts but I'm at a loss for why it won't even start/fire.

Any one have any ideas? My grass is currently about 3-4 feet tall And I really need to get it takes back again.

Thanks,
DaSpudro

If it's torquing the engine like u say, I would check that flywheel key again? Sounds like a timing issue to me?

DaSpudro · Aug 18, 2015

coinman66 said:
If it's torquing the engine like u say, I would check that flywheel key again? Sounds like a timing issue to me?

Pulled it appart again.... Yep sheared the key again. Brand new key and sheared in the first couple attempts. Is there a proper size that needs to be used? I lined up my original and came up with 3/16 x 5/8, but does any one know if this is correct? Inside the fly wheel on the bottom are about 6 curved magnets. 3 are loose and not equally spaced. You can remove them completely actually.... Do these need to be fixed in position and or equidistant apart? I assume this is for the charging system?

coinman66 · Aug 18, 2015

DaSpudro said:
Pulled it appart again.... Yep sheared the key again. Brand new key and sheared in the first couple attempts. Is there a proper size that needs to be used? I lined up my original and came up with 3/16 x 5/8, but does any one know if this is correct? Inside the fly wheel on the bottom are about 6 curved magnets. 3 are loose and not equally spaced. You can remove them completely actually.... Do these need to be fixed in position and or equidistant apart? I assume this is for the charging system?

I'm sure there is a specific size for flywheel key. Not sure about the magnets u are talking about, but I'm sure somebody will answer u eventually on here.

primerbulb120 · Aug 19, 2015

The magnets should be glued to the inside of the flywheel.

bertsmobile1 · Aug 20, 2015

DaSpudro said:
Pulled it appart again.... Yep sheared the key again. Brand new key and sheared in the first couple attempts. Is there a proper size that needs to be used? I lined up my original and came up with 3/16 x 5/8, but does any one know if this is correct? Inside the fly wheel on the bottom are about 6 curved magnets. 3 are loose and not equally spaced. You can remove them completely actually.... Do these need to be fixed in position and or equidistant apart? I assume this is for the charging system?

As previously mentioned. magnets should be glued to the flywheel.
Loose magnets can jamb the fly wheel and usually wreck the stator to boot.
Magnets also need to be very evenly spaced or you end up with nast peaks in the voltage which gives th rectifier grief.
Pounding on the flywheel with a 10 lb hammer is what usually causes them to shift.
Do not even think of putting it back together with dodgy magnets.
I have never had any luck glueing them back on but if some one knows of a glue that will take the heat & vibes please let me know I have about 20 flywheels in the scrap metal bin at the moment.

DaSpudro · Aug 20, 2015

thanks for the info.

Tuesday night I just decided to go with my gut and glue the magnets back on. i took and used a wire wheel to clean the surfaces of both the fly wheel and magnets, then used some brake parts cleaner to get off any oils. i then sanded with 150 grit and blew all the dust out with my compressor and resprayed with brake parts cleaner and wiped dry with a rag. I used steel JB-Weld which I have used for exhaust leaks and has been known to fix and seal cracks in engine blocks, though i'm not sure i would use it for that. so it should hold up to both the heat and vibrations this motor will generate. i made sure the magnets where evenly spaced and close to level and after an hour or two i went back out and trimmed of all the excess "weld" and let it sit and cure for 24 hours in my garage.

the next day (yesterday i came home from work, took the ready flywheel out and put a new Woodruff key in it. i found the factory specs do list a 3/16 x 5/8, so i do have the right sized key. i marked where the flywheel is compared to the crank so i could more easily detect if the key sheared again. i removed the spark plug and rotated the cylinder a handful of times to make sure it didn't bind up or have any rough areas. it rotated smooth so i put the plug back in and tried to fire it. it partially cranked and died again so i checked the alignment with the crank and flywheel, all was good so i repeated this process about 4 more times until it finally fired and ran smooth and for the first time all season i was able to mow my lawn without borrowing a friends mower.

time will tell if my "fix" holds up, but for now it looks to be resolved. Thanks for the help and hopefully this will help someone else in the future.

Kohler courage 20 (sv600) cranks but won't start and backfires.....

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