Farmall Cub

Compression test.

Check the spark plug wire locations on the magneto. Doesn't look correct.

Post by Eugene » Mon Aug 11, 2014 8:33 am

Compression test.

Check the spark plug wire locations on the magneto. Doesn't look correct.

I agree the number 1 wire should be on the top tower. Pull number 1 spark plug and rotate until you come up on compression, then remove the cap to see where the rotor is pointing.

Copy that. Thanks for the constant attention on this thread, everyone. I cant wait to get back at it! If anybody wants to give anymore input, please by all means do so! I want to have as much info and direction as possible to make my time with the tractor as valuable as possible. Currently it's in another state and with my shift work, husband duties, kids, and life in general, I get very little face time with it. I'll keep exploring the wealth of knowledge archived in this forum in the meantime when I have a few minutes.

My immediate goals are to get it up and running for Field Days of the Past and to use it for Halloween night. Last year, I used my Cub to attach an old 8x8 wooden rail trailer with hay bails to tote my family around in from house to house. Id love to get the A in there this year.

In wanting to rule out the coil being faulty, I am going to buy a new one. In my research, I am still confused. This being originally a 6v tractor, do I need to continue in buying a 6v coil? I am ultimately wondering if the electrical systems are different from the starter in that if I am using this 12v battery to crank the engine, is that going to blow anything else in the system that is 6v? Would I have to change the generator or is that the magneto that is producing the 6v to power the coil to the distributer, spark plugs, regulator and so on?

Bottom line: The guy who rebuilt the starter said he made it compatible with 12v (I figured 6v was fine and that the 12v would just turn it faster) so what else now has to be changed? Sorry for the mechanical/electrical confusion.

Don't replace the coil just yet. If you are getting a nice blue spark, the coil should be OK. Or at least OK enough to at least fire.

I read through this thread and someone mentioned that it backfired. If that is the case, check your timing again. Procedure to time your mag is similar to a Cub mag timing. Loosen the mag mount bolt, turn the top of the mag towards the engine, turn the engine over with a crank until #1 comes up on compression. Rotate the top of the mag away from the engine block JUST until it trips and tighten it down. Look inside the cap and see where the rotor is pointing. That should be your #1 spark plug tower on the Distributor cap. If it isn't pointing there, then there is a problem in the timing.

Triple check the plug wires that they are in the correct order - 1-3-4-2 clockwise on the distributor cap.

Mike

Thanks for the reply Mike. What would cause the engine to go out of timing? If it was stored running, how could it be out of timing? Sorry for the confusion on my part. Google-ing now as to what may have caused that.

So a couple days have passed. I have used Google and asked around but cant find the answer. What would cause these engines to no longer be in correct time?

You are correct that it should be similar to the condition it was last stored in. In order for it to be way off, someone would have changed something (plug wires, points, or timing adjustment, etc.) However, you don't really know the last time the tractor ran correctly, so you have to start at basics, and insure timing is all set up correctly. On a smaller scale, just filing the points will shift your timing, because it changes the point in time when the spark occurs.

raystractors wrote:.......
I agree the number 1 wire should be on the top tower. Pull number 1 spark plug and rotate until you come up on compression, then remove the cap to see where the rotor is pointing.

That magneto appears to be rotated a long ways clockwise (spark advanced) which puts the #1 wire which is normally the next one CW past the clip holding the cap farther around and down than is normal.

Well I got the engine to fire today. In looking back, Im wondering if I should have primed the pump. I had changed the oil and filled the oil canister when I initially changed the oil as well but am worried that in the excitement of getting the engine to fire, I may have caused damage. I doubt there was any damage but the engine heated up really fast (may be because I dont have the timing exactly perfect and the exhaust valves are closing late) and I dont know how long it took for the oil to work its way to the cylinder. I figure tractors sit for weeks at a time so what's the difference when the oil I poured into the canister would have eventually leaked back into the oil pan just like any other time right?

The oil pressure guage showed great oil pressure during the time that I had it running.

Any reassurance or construcive criticism is appreciated as I want to know if I'm likely okay or if I made a stupid mistake. Thanks!

Here's the video of it running for the first time:


http://s1296.photobucket.com/user/AgTir ... a.mp4.html

I ran it about 3x after this for about the same period of time.

If you got oil pressure quickly, you're good.

Denny Clayton wrote:If you got oil pressure quickly, you're good.

I wish I knew how quickly oil pressure built but I only went to look after the first 2 runs like in the video. I kept hearing a "tap tap tap" while it was running. This is what got me thinking about it in the first place.

Looks like you are running it off pure ether. Wouldn't do too much of that, could be why it is running hotter, and it will wash down the cylinder walls removing the oil. Get a pony tank hooked up and use gas.

Does it have water in the radiator? That tap tap tap may be a valve sticking , Like Rick said hook a pony tank up to it

Ah thanks guys! I didnt think about washing down the cylinder walls... OOPS!

Before I can get it to run again, I'll be taking the carb apart and getting it to run the way it is supposed to. Is there anything else I should be aware of? Should I squirt some oil into the cylinders hoping to get that ticking valve to work free?

There is water in the radiator. It took 2.5 gallons and started dripping from an unknown location. I guess I have to track down a pin-hole somewhere. Would anybody advise against any variation of Stop Leak? OH and before I forget, there's a cut wire coming from where the radiator connects to the bottom of the block (Im guessing the thermostat?). Is that for a gauge?