Cub LT1045 Cranks but Won't Start

[MPVawter]

I was mowing with my Cub LT1045 and shut it down it add fuel. Unfortunately, it hasn't started since. The engine cranks fine but does not try to start. On the first few attempts, the engine backfired through the exhaust. Now it only cranks....

So far I have done the following:

* Verified spark by pulling plug from cylinder, grounding plug to engine, and cranking. Appears to have good spark?? I also replaced the plug.

* Tested the fuel shut-off valve on the carburetor. It appears to be working.

* Verified that the float bowl is full of fuel.

* Replaced the fuel filter.

* Replaced the oil and filter. Engine oil level is correct.

* Verified that the flywheel key is intact

What am I missing??

 

[OldMachinist]

Try a spraying some starting fluid in the carb and see if it starts. Did you take the flywheel off to verify the key? The only other thing I can think of is a compression test but you said it was running till you shut it down.

 

[MPVawter]

Thanks for the suggestion. When I sprayed starting fluid into the carburetor, the engine backfires as loud as a shotgun. Also, I did pull the flywheel to verify that the key was intact. I guess that I need to check the compression.

 

[dqdave1]

Remove flywheel and replace the key. When it backfired it sheared or "partially sheared the key. It is now out of time and will not run. Key will look good; must remove flywheel.

 

[gammata]

Hve you got all your safeties interlocked seat brakes clutch etc.?

 

[buzz999999]

I have exactly same problem...how did you rectify???!!!

 

[rcbe]

I have exactly same problem...how did you rectify???!!!

Buzz - you will need to do same as DQDAVE said to OP earlier - remove flywheel, clean bore, shaft and keyway thoroughly - install new OEM key (no aftermarket) - re-asm flywheel and retorque (usually 100 ft/lbs -chk kohler website). Be careful not to break fins on flywheel . Take to cub cadet shop if you are not comfortable with such a repair. Good luck

 

[buzz999999]

Thank you for your help....I did the same....keyway was sheared. had to go to lowes and fab a keyway (used stock 3/8 aluminum- figured it was just there for aligning)...torqued to 67 n-m and it started....having a little oscillating reving at med. to low rpm. might change new fuel pump back to old....any suggestions.

 

[rcbe]

go to kohler engine website - d/l both parts list and service manual for that engine in order to get correct p/n for replacement crankshaft key (mtl and hardness important) and also to get correct retorque value when re-asm flywheel ( make sure flywheel bore, key, keyway slot and crank absolutely clean before asm).... use rattlecan carb cleaner to chk for intake leaks while engine is idling - a shot or two around pheriphery of assy and engine speed changes tells you there is a leak...repair as req'd - then a tad of seafoam directly down carb throat and also some into fuel tank - should see improvement.

 

[Bob_Bainbridge]

Thank you for your help....I did the same....keyway was sheared. had to go to lowes and fab a keyway (used stock 3/8 aluminum- figured it was just there for aligning)...torqued to 67 n-m and it started....having a little oscillating reving at med. to low rpm. might change new fuel pump back to old....any suggestions.

I wouldn't recommend using aluminum for a key. It will probably shear in no time. It shouldn't be too hard to find a stell key the right size. They're pretty common.

Bob B.

 

[buzz999999]

i ordered a key from the manufacturer and will replace when i get it. my research said that the key was only there for alignment and that the torque on the flywheel bolt was really what holds it in place. That why i figured a lighter metal wouldnt hurt. i bought a torque wrench and was careful to install it a 68 n-m.....is that right or do i need to change again when i get factory key. Also there was a question of air getting in system. I removed the fuel solenoid but after a bench test I re-installed it..could the air be coming in there.

 

[buzz999999]

Just FYI i read elsewhere there was a recall because the flywheel bolt had not been torqued...indeed I spun it off with my fingers.

 

[rcbe]

i ordered a key from the manufacturer and will replace when i get it. my research said that the key was only there for alignment and that the torque on the flywheel bolt was really what holds it in place. That why i figured a lighter metal wouldnt hurt. i bought a torque wrench and was careful to install it a 68 n-m.....is that right or do i need to change again when i get factory key. Also there was a question of air getting in system. I removed the fuel solenoid but after a bench test I re-installed it..could the air be coming in there.

good. the correct key has the proper properties to only shear when appropriate to protect vital engine parts. Also getting the correct kohler engine service manual will give you the right torque value for the flywheel bolt which is critical. Fuel solenoid - if you are talking about the afterfire solenoid that is located at the bottom of the carb, as long as raw fuel does not leak out around threads,you should be ok. Use the rattlecan spray carb cleaner to check for air leaks where the carb assy joins up with the engine, etc. - while the engine is running. if the engine rpm changes momentarily just after the spray is applied externally, then there is a air leak and need to be repaired - usually by installing a new gasket at that particular connection.
take your time, work clean, take plenty of before/after pix when working around carb - easy to get lost on re-hooking up stuff.

 

[me4gh4n]

im having the same issue it ran for a good while then i refueled and it ran for about 5 mins and sputtered and stopped running it cranks but wont start everything is working properly but still wont start it has enough oil fuel etc not getting why i have gas in the carb but wont start

 

[The kid]

im having the same issue it ran for a good while then i refueled and it ran for about 5 mins and sputtered and stopped running it cranks but wont start everything is working properly but still wont start it has enough oil fuel etc not getting why i have gas in the carb but wont start

This is quite an old thread but good info. Do as the above mentioned and download the service manual and replace the flywheel crankshaft key. I found an exact replacement for mine at TSC for a few dollars. Take pictures of your engine as you start removing screws and such to help when reassembling. You can either purchase a Kohler flywheel puller. Do a google search on removing the flywheel. There are other methods where one can use only a hammer to get it loose, but carefully. The danger of using the hammer method is damaging the fins or jarring a magnet loose that are glue mounted under the flywheel which effects the charging circuit. I also bought a flywheel puller at TSC. Good luck. -kid