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Ironhorse1077

1977 C-120 8spd runs and then shuts down

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Ironhorse1077

Battery charged, new cables, connections cleaned up, new spark plug, new air filter, ethanol free fuel, etc.

Tractor will start and run - for a bit,.... then is shuts down.

A friend thinks the coil may be overheating.

 It may need a head gasket - would that cause these symptoms?

Maybe the carb needs rebuilt - clogging up with old bits of fuel line?

I think today I may attempt to peek in at the points,.....

 

I am finding it is both a blessing and a curse having multiple tractors - more fun, more headaches, more expense, more knowledge, more maintenance, more choices, more storage space, more options for towing a broke-down tractor back home from the neighbors house!  :blink::wacko:

 

 

 

 

 

 

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gwest_ca

You should be able to determine if the points are the problem without disturbing anything. As soon as the engine quits would be the best time to check.

 

Check the voltage at the (+) side of the coil. Should be close to battery voltage with key in RUN position.

 

Now watch the voltage at the (-) side of the coil as the engine turns or is running.

When the points are open the (-) voltage should be the same as the (+) voltage. If it is not there is leakage to ground. That could be a shorted wire or condenser failure.

When the points are closed the (-) voltage should be 0 volts. If it is not the points are not providing a good solid ground for the (-) wire. This is called point resistance and there should be none.

 

This happen pretty fast if the engine is running.

You may have better luck watching it by removing the spark plug and turning the flywheel screen by hand. This on-off cycle happens once for every two turns of the flywheel.

A test light will work if you don't have a voltmeter.

 

Garry

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squonk

When it shuts off, does it start right back up or does it have to sit awhile? 

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rmaynard

Check to see if the vent in the gas cap is clogged. If you loosen the cap and it starts and keeps running, you've found your gremlin.

 

This is not to say that the above suggestions are not valid, but always try the easy stuff first.

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Ironhorse1077

Thanks all!  I will try these suggestions today.  Much appreciated advice!  :bow-blue::handgestures-thumbupright:

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scotty

My b-80 did that once and it ended up being the plug wire.

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Ironhorse1077

In response to Squonk - Both.  It happens intermittently.  

 

Again, thanks.

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