Repairs kohler cv15s runs about 20 mins and backfires and stalls

[kevin887]

hi i have a john deere with a 15 hp command engine mod.# cv15s it backfires and stalls let sit a few minutes and it restarts.?
I've changed fuel filter
also put a new carb. on it
replaced the spark plug
it seemed to be fixed i ran it for 3 hrs and it ran fine. About 3 or 4 hrs. i had to move it out of my shop to get another mower in as it was idling its stalled again when i got it back in my shop it started backfiring an wouldn't start it had plenty of spark. it sat a few mins. and it started up like nothing was wrong? i have never come across this problem can anyone help me? someone said its the hydraulic lifters sticking but i'm not sure
CAN ANYONE HELP ME OUT?
thx
kevin

 

[mechanic mark]

http://www.kohlerengines.com/onlinecatalog/pdf/tp_2339_d.pdf See section 3 troubleshooting.

 

[ILENGINE]

My first thought was fuel solenoid on the carb cutting out, but you said that you installed a new carb. Could be lifter related, there has been a few isolated cases where the lifters would over pump lifting the valves off their seats, due to incorrect grade of oil. Using straight grade oil, or oil with too high of a viscosity. Could be ignition module related also, will need to check for spark at the time of failure.

 

[kevin887]

My first thought was fuel solenoid on the carb cutting out, but you said that you installed a new carb. Could be lifter related, there has been a few isolated cases where the lifters would over pump lifting the valves off their seats, due to incorrect grade of oil. Using straight grade oil, or oil with too high of a viscosity. Could be ignition module related also, will need to check for spark at the time of failure.

hi it did have plenty of spark when it happened
i hooked up an in line spark plug tester

 

[kevin887]

My first thought was fuel solenoid on the carb cutting out, but you said that you installed a new carb. Could be lifter related, there has been a few isolated cases where the lifters would over pump lifting the valves off their seats, due to incorrect grade of oil. Using straight grade oil, or oil with too high of a viscosity. Could be ignition module related also, will need to check for spark at the time of failure.

hi i replaced the lifters and new head gasket and now it just backfires and don't start up. can you please help because now i'm stumped?
thank you any help
kevin

 

[shiftsuper175607]

hi i replaced the lifters and new head gasket and now it just backfires and don't start up. can you please help because now i'm stumped?
thank you any help
kevin

Loosen the gas cap when it happens and see if the tank is under vacuum and preventing fuel flow.

 

[ILENGINE]

Check the flywheel key to make sure it isn't sheared or offset. Will effect timing.

 

[kevin887]

Loosen the gas cap when it happens and see if the tank is under vacuum and preventing fuel flow.

did that still backfiring new carb i put in also new fuel filter

 

[kevin887]

Check the flywheel key to make sure it isn't sheared or offset. Will effect timing.

hi i just pulled off the fly wheel and the flywheel key is like new no offset burrs keyway looks fine as well. before i changed the lifters it would at least start and run awhile then backfire and stall if tried to start it right away it would just backfire but if sat a 2 to 5 mins. it would start and seem to run fine. but after awhile it would start doing the backfiring thing. this is what i done so far:
1. change with new carb.
put new fuel fitter
2. checked the plug when the problem occurred and has plenty of spark it i checked it with an inline tester
also pulled plug and checked against engine block and that had plenty of spark.
3. did the fuel cap vent check but loosening it when the problem occurred same thing no change.
4. new hydraulic lifters.
5. new head gasket. the old one did seem compromised though.
6. i pulled fuel line off carb. inlet an turned engine over and it's pumping fine.
7. took off flywheel and the keyway and key are fine.
8. took valve cover back off and the non adjustable rocker arm are torque tight
with oil pumping thru push rods when i turn the flywheel.
I AM STUMPED READY TO BREAK OUT THE DYNAMITE!!!!! any help will be so appropriated like a miracle.
thank you kevin

 

[kevin887]

hi i have a john deere with a 15 hp command engine mod.# cv15s it backfires and stalls let sit a few minutes and it restarts.?
I've changed fuel filter
also put a new carb. on it
replaced the spark plug
it seemed to be fixed i ran it for 3 hrs and it ran fine. About 3 or 4 hrs. i had to move it out of my shop to get another mower in as it was idling its stalled again when i got it back in my shop it started backfiring an wouldn't start it had plenty of spark. it sat a few mins. and it started up like nothing was wrong? i have never come across this problem can anyone help me? someone said its the hydraulic lifters sticking but i'm not sure
CAN ANYONE HELP ME OUT?
thx
kevin

My first thought was fuel solenoid on the carb cutting out, but you said that you installed a new carb. Could be lifter related, there has been a few isolated cases where the lifters would over pump lifting the valves off their seats, due to incorrect grade of oil. Using straight grade oil, or oil with too high of a viscosity. Could be ignition module related also, will need to check for spark at the time of failure.

hi i just pulled off the fly wheel and the flywheel key is like new no offset burrs keyway looks fine as well. before i changed the lifters it would at least start and run awhile then backfire and stall if tried to start it right away it would just backfire but if sat a 2 to 5 mins. it would start and seem to run fine. but after awhile it would start doing the backfiring thing. this is what i done so far:
1. change with new carb.
put new fuel fitter
2. checked the plug when the problem occurred and has plenty of spark it i checked it with an inline tester
also pulled plug and checked against engine block and that had plenty of spark.
3. did the fuel cap vent check but loosening it when the problem occurred same thing no change.
4. new hydraulic lifters.
5. new head gasket. the old one did seem compromised though.
6. i pulled fuel line off carb. inlet an turned engine over and it's pumping fine.
7. took off flywheel and the keyway and key are fine.
8. took valve cover back off and the non adjustable rocker arm are torque tight
with oil pumping thru push rods when i turn the flywheel.
I AM STUMPED READY TO BREAK OUT THE DYNAMITE!!!!! any help will be so appropriated like a miracle.
thank you kevin