Craftsman 917.370430 won't start

[Gord Baker]

Hi all,
I am working on this mower and she won't start.
Cleaned carb with brushes and wire it is definitely getting fuel.
New air filter. Drained fuel tank and using new fuel.
Plug measures 15000 ohms which is good and light tester
lights when cord pulled. Sometimes pull cord kicks back and
sometimes there is a small back fire through the carb.
Checked flywheel shear pin and looks great.
Any other ideas?
Many Thanks in Advance.
PopIggy

You need to remove the Flywheel to properly check the key. Perhaps you just looked at it.

 

[Gord Baker]

If your Flywheel Key is in perfect condition try a new spark plug.

 

[Bud57]

Sometimes you can get kick back if there is no blade on it.

 

[The Maintenance Guy]

Hi all,
I am working on this mower and she won't start.
Cleaned carb with brushes and wire it is definitely getting fuel.
New air filter. Drained fuel tank and using new fuel.
Plug measures 15000 ohms which is good and light tester
lights when cord pulled. Sometimes pull cord kicks back and
sometimes there is a small back fire through the carb.
Checked flywheel shear pin and looks great.
Any other ideas?
Many Thanks in Advance.
PopIggy

Evil spirits...

 

[kjonxx]

Bad valve adjustment ??

 

[chuckpen]

if it snaps back hard on you then the flywheel key could be it or the exhaust valve is not set correctly and or the compression release is not working.

 

[Gord Baker]

Try some Quick Start spray. Hold Handle tightly. If it fires, it is not a Fuel or Ignition Problem

 

[sarg13]

Hi all,
I am working on this mower and she won't start.
Cleaned carb with brushes and wire it is definitely getting fuel.
New air filter. Drained fuel tank and using new fuel.
Plug measures 15000 ohms which is good and light tester
lights when cord pulled. Sometimes pull cord kicks back and
sometimes there is a small back fire through the carb.
Checked flywheel shear pin and looks great.
Any other ideas?
Many Thanks in Advance.
PopIggy

Hi, have had similar issue to this , where the valve seat had migrated out of position and was not sealing on the valve, would backfire out of the carby, also a stuck valve will give similar symptoms.
if you spray some brake cleaner in carby and it starts for a bit then you may have fuel supply issue, otherwise check inlet and exhaust valves are operating ok, and if you can do a compression test that will confirm it….good luck.

 

[clfrank13]

Hi all,
I am working on this mower and she won't start.
Cleaned carb with brushes and wire it is definitely getting fuel.
New air filter. Drained fuel tank and using new fuel.
Plug measures 15000 ohms which is good and light tester
lights when cord pulled. Sometimes pull cord kicks back and
sometimes there is a small back fire through the carb.
Checked flywheel shear pin and looks great.
Any other ideas?
Many Thanks in Advance.
PopIggy

Based on your info, sounds like the timing is off so if the flywheel key isn't sheared as per your report, could be a broken camshaft. The Camshaft shouldn't break unless you hit something and the camshaft gave instead of the shear pin. I would make sure the valves are properly opening and closing as you next troubleshooting step.

 

[nbpt100]

Based on your info, sounds like the timing is off so if the flywheel key isn't sheared as per your report, could be a broken camshaft. The Camshaft shouldn't break unless you hit something and the camshaft adequate. instead of the shear pin. I would make sure the valves are properly opening and closing as you next troubleshooting step.

It does sound like the timing is off which would mean a sheered key. However I would definitely leak down test and see if the valves are leaking and if compression is adequate. Also check for air intake leaks.