no start 48 cub

CalvinS · May 5, 2012

need help please!! cub running fine. put up, got back out next day and will turn over but no start. has fuel, spark (pulled plugs and checked) and good compression (at least 110 in all cylinders) hear mag clicking when trying to start. will pop occasionally. any help greatly appreciated thanks !!

Anonymous-0 · May 5, 2012

I assume you've checked the obvious; spark is getting to the plugs. Plugs are firing etc.
My cub had a little rust in the fuel tank. On a few occassions the little screen in the carb would plug up. No start. I figured it out by taking the plug out of the bottom of the carb. There was fuel getting to it but none running out of the bottom. or,
Might try pulling it in 3rd gear just to get it going. Sometimes that will work.

El Toro · May 6, 2012

Remove No1 plug near the radiator and bring that piston to TDC on the compression stroke. Hold your thumb over the plug hole while a helper hand cranks the engine slowly until you feel pressure against your thumb. Once you feel pressure have the helper to keep slowly cranking
til you lose pressure. Your timing marks should now be aligned. Remove the cap on the mag and see where your rotor is pointing. It should be at the No1 plug tower that's about 1 o'clock.

If the rotor is off a lot and you're certain No1 piston is at TDC on the compression stroke. Something in your engine may have failed like a woodruff key on your cam gear. Try pull starting before tearing into the engine. Hold your hand over the throat of the carburetor and have a helper try to start the engine. See if there's good suction on your hand. Poor suction means low intake manifold vacuum. You have good compression so I think you should have good suction. Hal

CalvinS · May 6, 2012

Thanks Ill try that, appreciate the replies

no start 48 cub

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