Engine Cub Cadet 1515 turns over but doesn't fire up

Johnnyboy

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I have a Cub Cadet 1515 lawn tractor with a 15hp Kohler OHV engine purchased in 2002 that won't fire up. It has spark however I suspect that it is not getting fuel because the spark plug looks dry. I disconnected the fuel line from the carb and practically nothing came out. I lowered the gas line below the position of the gas tank and gas comes out. Since the gas line has a uphill travel to get to the carb, it there a vacuum that should occur that draws the gas to the carb ? Does anyone have any troubleshooting steps I could follow to isolate this problem ? Thanks
 

bertsmobile1

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Unfortunately your mower has the somewhat infamous Kohler mechanical fuel pump.
These either work faultlessly forever or drive the owners insane .

Start by verifing the fuel supply to the pump by pulling off the fuel line and see if you can get a good fuel flow.
If not remove the fuel tank and clean it out paying particular attention to the fuel outlet pipe which oft have casting fins partially blocking them.

Once fuel supply is confirmed, remove spark plug and block the fuel pump inlet with your damp finger while cranking the engine . You should feel strong suction.

If not pull off the fuel pump and replace the pump diaphragm . There is a 50:50 success rate with these diaphragms which is why you leave it to last.
 

Johnnyboy

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I have a Cub Cadet 1515 lawn tractor with a 15hp Kohler OHV engine purchased in 2002 that won't fire up. It has spark however I suspect that it is not getting fuel because the spark plug looks dry. I disconnected the fuel line from the carb and practically nothing came out. I lowered the gas line below the position of the gas tank and gas comes out. Since the gas line has a uphill travel to get to the carb, it there a vacuum that should occur that draws the gas to the carb ? Does anyone have any troubleshooting steps I could follow to isolate this problem ? Thanks

Thanks for the tips as I will try them later today and see what happens. When I said I disconnected the fuel line from the carb, it was actually from the fuel pump. Sorry, I'm still learning about this machine.
 

Johnnyboy

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I have a Cub Cadet 1515 lawn tractor with a 15hp Kohler OHV engine purchased in 2002 that won't fire up. It has spark however I suspect that it is not getting fuel because the spark plug looks dry. I disconnected the fuel line from the carb and practically nothing came out. I lowered the gas line below the position of the gas tank and gas comes out. Since the gas line has a uphill travel to get to the carb, it there a vacuum that should occur that draws the gas to the carb ? Does anyone have any troubleshooting steps I could follow to isolate this problem ? Thanks

:thumbsup: After checking the fuel pump and noticing there was no fuel coming out of the output side of the pump, I replaced the fuel pump and everything is good now. The strange part is that when I compared the old pump to the new, the suction appears to be the same so I'm not sure why the old one is not functioning. So it appears the only way to test them is on the engine to see if there is fuel output. Thanks again for your help.
 
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