cub want crank

Thu May 16, 2013 11:33 am

I have a 1957 cub that i purchased a few of weeks ago. It was running great up until the last week. Was just ridding the other day and it shut off. The starter wire from the battery was loose . thightened it and it cranked just fine. well yesterday the same thing happened. It will turn over but will not crank. I have plenty of fuel. It is still 6volt system. It has a ext. coil. Any suggestions on where to start?

Thanks, Brad

Re: cub want crank

Thu May 16, 2013 11:53 am

Turn over and crank are the same thing, so you might get a few confused looks here... Both mean that the starter is making the engine rotate.

I assume you mean the engine is cranking but will not FIRE. Ok.

Since you messed with a loose wire before and it fixed the problem, this is likely to be an electrical problem rather than a fuel problem.

Have you checked for spark? There are so many "won't start" threads lately, it seems redundant going through the whole check for spark process... First thing is pull the center (coil) wire off the distributor cap and hold it near the engine block while cranking the engine with the starter. You should get a bright blue spark that jumps 1/4" gap.

If you get spark off the coil wire, try the old lawnmower test that your Dad probably taught you when you were a kid trying to figure out why the old push mower wouldn't run: Remove the spark plug from the front cylinder, put the wire back on it, and hold the threads against the engine block while cranking the engine over with the starter. It should make nice blue sparks.

Check for spark first and we'll go from there.

Re: cub won't crank

Thu May 16, 2013 12:10 pm


G'day to you and congrats on acquiring your new to you '57 Cub. Since you have a '57, I would be assuming that you have a battery ignition with the external 6v coil. When I get back home I will post the diagrams etc... (right now I am on-line at my Honda dealer passing time while they fix my TPMS :lol: ) Here is my take on this since the Cub is new to you, you should start at the beginning.

Check ALL the grounds and connections ensuring all metal connections including terminals are clean, bright and tight. A little dollop of di-electric grease is always a good extra. As Matt said, take the coil wire, stick a spark plug in it and hold it up against the block -- with a pair of insulated pliers :!: and turn it over - the spark should be bright blue -- not yellow. If yellow, check the points for glazing and gap and the condensor. Rotor too, don't forget that. Check the timing. Check the firing order (look in the CBoK - that stuff is all there). Make sure that all the plugs are clean and gapped correctly.

Should start after that. If not well we will work on that with you. There are lots of resources available for our members, suggest you follow the links below and read up on your Cub and the other good stuff -

Image to :big smile: Forum Family. And you have come to the right place for all things Cub related. If you click on the Site Rules, Regulations, & Important Information, it will point you to :arrow: the Welcome Wagon wherein you will find links to many useful sites and topics. One of which is the Cub Manual Server. Enjoy!.

Re: cub want crank

Thu May 16, 2013 4:02 pm

thanks guys. will try this when i get home from work and let you know what happens. again thanks

Re: cub want crank

Fri May 17, 2013 9:13 am

Hello, Guys
Well i got home yesterday and took a test light and started checking the coil to see if i had fire coming from the points and to make sure they where opening and closing. As soon as I started turning it over it fired right up. ?????????????????????????????? I let it run for about an hour with no problems. Went out about 2 hours later just to see if it would crank, and it did just fine. So I still have no clue too why it has been shutting off. I guess i will wait and see if it happens again. Just wanted to say thanks for the help!!! I'm sure i will calling on y'all again. I love my new tractor. Wish I could show it off alittle on here. The guy I bought it from did a great job restoring it.

Again, Thanks

Re: cub won't crank

Fri May 17, 2013 10:14 am


Glad you got her started. Sometimes it is just a gremlin :big give up:

As far as this:

bradbradford2525 wrote:Wish I could show it off alittle on here. The guy I bought it from did a great job restoring it.

On The Forums wrote:

Re: cub want crank

Fri May 17, 2013 1:15 pm

Hmm, so I guess you have spark! :)

That has all the earmarks of a flakey ignition switch or loose/broken/frayed ignition wire. Tough to trace because the ignition wire disappears into the main wiring loom that runs from the dash panel to the generator, then appears again near the coil.

If it does it again, try bypassing the ignition switch and wire by running a wire directly from the - on the battery to the coil. When that makes it work, install a new wire from the switch to the coil, tastefully, by following the main loom and using small zip-ties to secure it along the way. You can leave the old wire in place, because it would be a major problem to remove it.