cub will not start.

garyandnancy · Dec 28, 2009

I’m working on a neighbor’s cub that will not start, and I’m stumped. When I crank it, it will sputter a bit, sounds like on all four cylinders, but will not run. Here is what I have done:
-Compression on each cylinder is between 90 and 110
-Points are opening just as #1 cylinder is at TDC. I confirmed this with a multi tester.
-Using a timing light, I have confirmed that #1 is getting spark just right at TDC
-Plug wires are correctly connected, 1 – 3 – 4 -2
-I took the carburetor apart, passages are clean, all right parts are there.
-I checked for a vacuum leak on the manifold, was not able to find any problem.

It seems like it should run, clearly I am missing some thing that is messing things up. Any ideas?

Thanks
Gary

bg/mo · Dec 28, 2009

what about fuel?

farmlife · Dec 28, 2009

Be sure and check the batttery wire going to the coil. Have seen the insulation stripped off and grounding out intermittently. Can drive you nuts!

james rumph · Dec 28, 2009

Did you put points in it ? If you did are you sure you used the insulators between the distributor housing and the power wire.

Did you take it apart ? The screws that hold the points plate a certain length and if to long they hit the advance weights and it won't start.

Did you just clean the carb out or did you install a cheap rebuild kit.

If you rebuilt it with one of those Tractor Supply kits that is the hole problem. "JUNK" ..

ScottyHOMeY · Dec 28, 2009

Is this a new problem, as in it was running recently but quit? Or has it been setting for many moons?

old popper · Dec 28, 2009

Check to see that the fuel line is delivering a constant ample supply to the carb. Just an idea.

Anonymous-0 · Dec 28, 2009

My cub wouldn't start until I found that the spark was crossfiring in the distributor cap.Replaced cap, rotor, and points and it has run well ever since.

El Toro · Dec 28, 2009

Pour several teaspoonfuls of gas on top of several pistons then reinstall the plugs and see if it will fire like its going to start. If it does it means you're not getting gas to the engine. You should be able to hold your hand over the throat of the carburetor to make it start. Pull the gas line at the carb and see it there's a full stream of gas from the tank. Catch the gas in a clean container. Make sure your plug wires are in this firing on the cap. Hal

2-1
4-3 Rotor turns CW.

sgtbull · Dec 29, 2009

are you sure that you are tdc on COMPRESSION not exhaust? sounds silly, but it happens.

cub will not start.

garyandnancy

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bg/mo

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farmlife

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james rumph

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ScottyHOMeY

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old popper

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Anonymous-0

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El Toro

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sgtbull

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