Thursday, May 26, 2011

Please Help My Farmall!

I have an old tractor, and when it's running it's a blast.  I like to fire it up, drive it around.  It isn't fast.  It sure isn't pretty - the thing is desperately in need of a bath.  It isn't even useful.  It has no hitch hardware, and the PTO currently doesn't work.  That doesn't stop me enjoying the thing...but I only enjoy it when I can imagine using it for something useful, even though I never have.

When it's in running condition, I like to fire it up by turning on the ignition, giving the starting crank a mighty yank, and off she goes.  Check to make sure it's in neutral before doing this; early tractors like this one had no such thing as a safety switch to guarantee no starts in gear.  If it's in gear when you start it, well, it might run you over.

But that's assuming it'll start.  That seems to have gone by the wayside, so I'm putting out a feeler to the entire Internet and I'm hoping someone will give me the benefit of their wisdom.

I had it running late last year, no problem.  I shut it down, then went to start it again.  Nothing.  In the space of a few minutes, something had failed and that killed it utterly.


Well, that was pretty frustrating.  I assumed, and I think I'm right, that it was an electrical problem.  The thing with these old Farmalls is that there almost isn't an electrical system.  If you don't have a battery, no sweat: the Farmall has a magneto system that generates the running spark.  You don't even have to have a generator or alternator on it, the mag does it all.

So here's my thing: I do okay at household electrical, but when it comes to vehicle electricals, it's like I've suddenly lost a lobe of my brain.  I need someone to weigh in, to offer some suggestions.

What I've done so far: checked for spark on plug #1: no joy.  Inline tester, no glimmer during cranking.

That's about all I can think of to do.  I don't know what else I can do, since the magneto is all one piece.  I guess the next bit might be to remove the mag and give it a spin, see if the impulse drive (a doohickey that gives the mag an extra kick at very low speeds, makes it easier to start when cranking) is working.  But I'm using the starter motor, powered by my truck's battery so there's plenty of twist to get things moving.

Enticingly, frustratingly, it coughed once or twice the other day while I was trying to get it going.  Just a little pop, "Rr-Rr-Rr-Rr*phut*Rr-Rr-Rr."  Enough to keep me hoping and trying and providing an endless buffet for the damned mosquitoes.

Anybody else want to sound off on this?  I freely confess my knowledge is limited.

If nobody wants to offer any thoughts, I'll pull the mag and take it to a shop that did some work on it for me a couple of years ago - the results from that were just stunning.  Maybe that's all it is, this time.

1 comment:

  1. Almost has to be a magneto problem. If it were plug wires or plugs, it probably would not have failed so suddenly and summarily.
    See if the magneto shaft is turning. If not, it could be a broken timing chain or distributor shaft.
    See if the impulse mechanism is working. If it is, the turning part in the mag jumps forward at certain places in the rotation.
    See if the cap or rotor is broken. That happens sometimes.
    If none of those, it is probably a short or open circuit in the coil.
    Another possibility is a misalignment between the coil and the rotating magnet so it's no longer generating enough spark. A magneto should be cleaned and greased once a year or so. If it was binding up, that might have caused a misalignment.