Cub cranks but won't start

Thu May 08, 2014 12:44 pm

I have a Cub that cranks great but won't start. I jump it and it cranks very fast but without starting but as soon as I release the starter button (while the motor is still spinning) it starts and runs great. Someone told me it sounds like either the coil or the starter is drawing too much electricity while it is cranking. Has anyone experienced this or know what it might be? I know it is not timing, points, plugs, etc. because once it starts it runs perfect.

Re: Cub cranks but won't start

Thu May 08, 2014 3:35 pm

Probably the ignition switch or solenoid based upon the statement that the tractor starts and runs when you release the starter button.

Is this a push button (actually a button on the dash) or a pull lever?

Assuming this tractor has a 6 volt battery, generator system. Also assuming the 6 volt battery cranks over the engine.

Need to know year of tractor, ignition wiring system, wiring original to tractor, magneto or etc. etc..

Basically need more information to narrow down the problem.

Re: Cub cranks but won't start

Sat May 10, 2014 9:22 pm

The Cub is a '59 Farmall Lowboy. It has the pull lever for the starter. It is at my mother's place (she still lives on the farm) and I was able to look at it today. It appears to me that it was converted to a 12 volt system but did not get the chance to check that today. The starter and coil both look fairly new.

Re: Cub cranks but won't start

Sat May 10, 2014 11:07 pm

How long has it been since the tractor last ran? Answer this question because if it has been a year or longer we need to prime the oil pump before starting the engine.

Probably one of two areas; ignition fault or fuel/carburetor problem. Two easy checks:

1. See if the fuel shut off under the tank is open and that there is fuel flow through the carburetor.

2. Check, see if you have spark while cranking over the engine.

Re: Cub cranks but won't start

Sun May 11, 2014 7:36 am

the lo-boy I got from Harold does the same thing , it has the key to turn on , then a push button ( like the old dimmer on the floorboard of autos ). it will turn the starter till the cows come home , but will not start till the instant you release it . you can "bump" the button and it will start , but if you hold the button down , it will just spin the starter. coppersmythe...........................................................edit : late model 12v,dist.
Last edited by coppersmythe on Sun May 11, 2014 12:55 pm, edited 1 time in total.

Re: Cub cranks but won't start

Sun May 11, 2014 9:30 am

do either have a mag?

Re: Cub cranks but won't start

Sun May 11, 2014 9:44 am

pechumbley wrote:The Cub is a '59 Farmall Lowboy. It has the pull lever for the starter. It is at my mother's place (she still lives on the farm) and I was able to look at it today. It appears to me that it was converted to a 12 volt system but did not get the chance to check that today. The starter and coil both look fairly new.
Is it possible the conversion was only partly doe, such as adding the dropping resister in series with the coil, but still has a 6 volt battery? That may give the results you are describing.

coppersmythe, check your coil. Since you said push button I assume it is 12 volts. Check the coil, it it has an external dropping resister and someone has replaced the coil with one having an internal resister that would do the same. Many cars had a wire that bypassed the resister for starting, not sure if the cubs with push button (solenoid) used that or not.

Re: Cub cranks but won't start

Sun May 11, 2014 12:57 pm

thanks , its raining cats and dogs ( great danes ) , good time to slip out of the honey-doo's and check out the cub :roll: . coppersmythe............................

Re: Cub cranks but won't start

Sun May 11, 2014 1:49 pm

I put a volt meter on the battery side of the coil and see how much voltage drop there is while cranking. works for 6 or 12 volt. then if voltage is to low I ( momentarily) touch a 12 or 6 volt jumper wire to battery side of coil and see if it starts. I hope this helps

Re: Cub cranks but won't start

Sun May 11, 2014 4:55 pm

Have you checked to see if you have fire at the sparkplug wires? get a start tester from the auto parts store, plug one end on the end of the wire, and the other clamps on the end of the plug, and crank it, you should see a spark. its possible for the wires to go bad.
you might need to check the coil, the points, the distributor cap, and the wire between the disturber and coil.
before doing any of this check to see if you have fuel getting to the carb, and check the adjustment screw on the car, turn it all the way in and back out one turn.
and lastly the ignition knob switch..

Re: Cub cranks but won't start

Mon May 12, 2014 4:33 pm

Also pull both battery connectors and make sure the inside of the cable post clamps and the posts on the battery are clean and bright. I had similar symptoms, and, although the connections looked clean, there was some pretty serious buildup on the inside of the ground cable post clamp. Cleaned that up and problem solved.