10-20 no fire

Working to bring a 1924 10-20 back to life. Ran when parked 5 years ago but rusty fuel tank kept clogging line. Decided to get it going again this winter.

E4a magneto was stuck so I took it apart and cleaned it up. The armature had rusted some and was stuck where it rotates along the face of the magnet. Tested it after it was back together and had good spark. Put it back on the tractor and timed it by the book. #1 piston on TDC of compression stroke, marks on flywheel aligned. The carburetor is off the tractor because I'm waiting for a new float to ship. Used the priming cups to give it a little fuel, cranked, no fire. Tried same thing again a few times, same result. Tried a little ether, still no fire. Hmmm.

Took #1 plug out, reconnected plug wire, clamped the plug to a good ground on the frame, and slowly cranked. Impulse coupling snapped and plug fired with good spark at TDC compression, can see piston is at top of stroke and marks on flywheel align. Did same thing with #2 plug with same result. Put plugs back in, primed with gas, and still no fire.

I spent the morning going back and rechecking timing and magneto every way I know how. I am stumped by this one. I don't understand why I get spark when the plug is out and grounded to the tractor, but don't get any fire when the plugs are installed. I even tried replacing the plugs with known good plugs from another tractor. I've timed enough of these old magnetos to well know the difference between the compression stroke and the intake/exhaust stroke, so it's not that.

Anyone have any ideas?
 
(quoted from post at 15:39:59 01/14/19) Working to bring a 1924 10-20 back to life. Ran when parked 5 years ago but rusty fuel tank kept clogging line. Decided to get it going again this winter.

E4a magneto was stuck so I took it apart and cleaned it up. The armature had rusted some and was stuck where it rotates along the face of the magnet. Tested it after it was back together and had good spark. Put it back on the tractor and timed it by the book. #1 piston on TDC of compression stroke, marks on flywheel aligned. The carburetor is off the tractor because I'm waiting for a new float to ship. Used the priming cups to give it a little fuel, cranked, no fire. Tried same thing again a few times, same result. Tried a little ether, still no fire. Hmmm.

Took #1 plug out, reconnected plug wire, clamped the plug to a good ground on the frame, and slowly cranked. Impulse coupling snapped and plug fired with good spark at TDC compression, can see piston is at top of stroke and marks on flywheel align. Did same thing with #2 plug with same result. Put plugs back in, primed with gas, and still no fire.

I spent the morning going back and rechecking timing and magneto every way I know how. I am stumped by this one. I don't understand why I get spark when the plug is out and grounded to the tractor, but don't get any fire when the plugs are installed. I even tried replacing the plugs with known good plugs from another tractor. I've timed enough of these old magnetos to well know the difference between the compression stroke and the intake/exhaust stroke, so it's not that.

Anyone have any ideas?


May still be firing when plug is installed but valves not seating due to rust or sticky valve guieds. How is compression? Maybe valve not seating well and causing it not to fire.
 
as I always say, check compression. plus add some oil to the cyl's. if that don't work belt it to another tractor. most time they have low compression from sitting dry.
 

Loren was right on...I put the carburetor on and she popped on the third crank. Started and ran well. Never would have guessed that.

Now I have to deal with a stuck clutch due to mice nests. It’s an early 10-20 with a multiple disc clutch.
 

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