I took the head off and things look pretty clean. The pistons are marked 020, so I am guessing that the engine was remachined at least once .020" oversize. There was a little bit of carbon buildup, on the piston tops at what appears to be right under the spark plugs. Came off quickly with a wire brush.
Does anyone know of a good source for Fairbanks-Morse magneto parts? I'm looking for a new condenser, cap, rotor, gaskets, etc. Points look real good however.
Mental note: when you first take the magneto off the tractor, don't hold it in one hand with your palm against the rotor cap and crank it over with the other hand. Those things pack a punch. At first you would think you would be able to turn it over slow without it making much of a spark. Well, I learned that it has some sort of device that winds up each quarter turn. And when it lets go it must turn that magnetic core over quick. Wow!
I can see why it can start an engine in 3/4 of a crank turn. I've been living too much in the fuel injected world. Where if it isn't connected to the engine and any wires, the part must be dead.
Is there any gizmo to measure spark energy? Something more quantitative than yellow or blue spark? Just curious...
Parts--NAPA may have something.
Landis Zimmerman will have it:
1450 Diamond Station Rd.
Ephrata, PA 17522
717-738-2573
As for the "quantitative" test for the spark--when I just have to know the answer--and I measure it in feet---I lick my fingers and hold on the end of the plug wire real tight while someone cranks her over---if I jump over three feet it is good:o:o:o:D:D
Seriously I don't know of any meter that will respond that fast. I'm sure there is one but blue works for me;);)
That's called the "impulse" Logskidder. That is what lets you start the tractor with 1/4 turn of the crank. Do a search for magneto parts suppliers and you should be able to find them. My magneto rebuilding friend just passed away, so I have no recommendations.
I bored the NAPA people for a while looking for parts for the Fairbanks-Morse Magneto. We found new points and a new condenser, but no gaskets, rotor or cap. I think they must have it, just a matter of finding it.
Online I found a website called www.magnetoparts.com (http://www.magnetoparts.com) and that guy seems to have the parts I need.
Well I put in the new condenser and WOW. Blue spark! tight and narrow, like a thin pencil line, at least a 1/4" long. Not yellow and wide. This time I wore an old pair of my dad's lineman gloves. Insulated to 10,000 Volts.
And I found the spark timing hole on the bellhousing. The hole is on the right side if you were sitting on it. but the hole is on the front of the bellhousing facing the front of the crawler. It made sense once I realized that in the boook they actually use the spark discharge of cylinder 1 to illuminate the line on the flywheel.