Farmall Cub

Had some time to work on "Ol Whitey," my white demo Super A yesterday...finally got the mag hot, (long story) and decided it was time to try to start it. Rigged up a pony gas tank, and after a few pulls of the crank, it did "hit" a time or two, which got my hopes way up. After a couple more trys, it suddenly became impossible to turn the engine with the crank. I was able to turn the engine backward by pulling on the fan blades, and it released and seemed ok but after a couple more trys it did it again, and I couldn't get it to turn loose. So I decided to call it a night.

I've hand cranked this engine a number of times and it has never shown any problem like this.

Any ideas what's binding it? I pulled the starter off just to make sure it wasn't jamming the flywheel (although I don't see why it would since I was hand cranking it.) No change. Though I have been around Super A's all my life, I'm not much of a mechanic, but my notion is there's an issue in the timing gears. Of course, those "hoofbeats I hear may not be zebras." In other words, it may not be that exotic of a problem. What else should I look for? I had high hopes of being able to hear it run before I did more extensive engine work, but that possibility appears to be fading fast...

Al

thanks,
Al

Stickey valve(s)

Bill E Bob wrote:Stickey valve(s)

I don't think valves are the problem, though I could be wrong. They all will move up and down by hand. Someone has had the valve cover off though, there's no gasket under it....

thanks,
Al

Will the engine turn freely when you pull the plugs? Do the plugs look wet?

VinceD wrote:Will the engine turn freely when you pull the plugs? Do the plugs look wet?

No, and no. Plugs have a nice generous coating of dry carbon. Again not trying to make a bunch of wild guesses, but after looking in each hole with a flashlight yesterday, I remmeber one cylinder in particular that was up near TDC so you could see a little of the piston. It got me thinking, I wonder if there's a big piece of dirt dobber nest, carbon, etc. that is making a piston contact the head? I can roll it backwards, I don't try to make a full revolution because I am afraid of damaging the mag impulse. Then if I roll it back forward, I can sometimes hear a little "clunk." I just can't tell where that "clunk is coming from.

I think I may rig up an attachment for my shop vac that will fit in the plug hole and see what I can vacuum out.

al

Well I figured it out! It was crap in the #2 and/or #3 cylinders. Flushed it out with my long-necked funnel and some gas. VERY relieved! I am going to pick up some new plugs tomorrow and see if I can get her to crank....


Al

Good deal, Al. Glad it was so simple.

Glad you found the problem and it was not more complicated. Could you identify the "junk" and any idea how it got into the two cylinders?

VinceD wrote:Glad you found the problem and it was not more complicated. Could you identify the "junk" and any idea how it got into the two cylinders?

Not really other than it wasn't metallic. I think it was carbon and other "junk" from sitting. THere wasn't a lot of it but just enough in the right spot. Also it was mostly in #2 and 3, don't they have the most "direct" path to the outside world through the manifold? That's what I was thinkning--if so they would get most of the dirt, etc. that "settled."

Al

I have seen carbon build up around a plug, then when the plug is removed, break off in big enough chunks to lock the engine.