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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

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

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.

ILENGINE said:

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.

Click to expand...

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

ILENGINE said:

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.

Click to expand...

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

kevin887 said:

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

Click to expand...

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

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

shiftsuper175607 said:

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

Click to expand...

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

ILENGINE said:

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

Click to expand...

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 said:

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

Click to expand...

ILENGINE said:

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.

Click to expand...

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