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Farmall A mag again

O

Olliejunkie

Well-known Member
I can't seem to get the rotor in the right spot. Right now number 1 is where number 2 would be. Is it possible that someone put the mag drive in the wrong spot?
 
Assuming it is for sure on TDC compression, the drive gear (in the front cover) could be out of time. It will assemble at any
tooth. The Mag drive is a slot. Jim
 
(quoted from post at 14:51:52 01/30/18) Assuming it is for sure on TDC compression, the drive gear (in the front cover) could be out of time. It will assemble at any
tooth. The Mag drive is a slot. Jim
Click to expand...
I think it is. The first time I removed the rotor I don't think it was lined up with the notch. It fits very tight. I now am thinking they put it on where to would run. Is there anyway to check the gear alignment without pulling the cover?
 
probably not cause the engine would not start or run as the valves would be out of time with the mag that's why there are timing marks on the gear that drives off the cam the two dots on that gear need to be lined up with the two dots on the cam gear. Like other post said the rotor can be timed with the tower on the cap.
 
(quoted from post at 15:03:14 01/30/18) probably not cause the engine would not start or run as the valves would be out of time with the mag that's why there are timing marks on the gear that drives off the cam the two dots on that gear need to be lined up with the two dots on the cam gear. Like other post said the rotor can be timed with the tower on the cap.
Click to expand...
Not possible to turn mag far enough to get it timed. That's is why I asked if I can tell if gear is timed right without removing front cover?
 
(quoted from post at 15:30:39 01/30/18)
(quoted from post at 15:03:14 01/30/18) probably not cause the engine would not start or run as the valves would be out of time with the mag that's why there are timing marks on the gear that drives off the cam the two dots on that gear need to be lined up with the two dots on the cam gear. Like other post said the rotor can be timed with the tower on the cap.
Click to expand...
Not possible to turn mag far enough to get it timed. That's is why I asked if I can tell if gear is timed right without removing front cover?
Click to expand...
I got into the mag a little further. Pulled off the cover under the rotor. There are right and left timing marks. Does anyone know which one to set it on for an A? Is it just right or left side of engine?
 
Use the "R" mark, for right (clockwise) rotation.

Turn the engine until cylinder 1 is as TDC. With the mag removed, you can see the orientation of the drive slot on the back of the governor. I believe it should be at 35 degrees off horizontal in a 2 o'clock - 8 o'clock position.
 
Thank you. That is what I was thinking and how it is timed. Should the rotor be pointing at 1 before or after it snaps over?
 
Thank you. That is what I was thinking and how it is timed. Should the rotor be pointing at 1 before or after it snaps over?
 
I think when we changed the points we must have moved the gears behind the rotor. I think I know almost everything there is to know about this mag now.. hopefully it will run tomorrow. I have had a w6 and a td6 for 20 years and have never touched the points. Maybe it will be the last time for this one.
 
Olliejunkie:"Should the rotor be pointing at 1 before or after it snaps over?" Don't worry about that level of detail. If you get the gears meshed properly to the "R" mark, when the drive lug is in the right place, the rotor will be somewhere near only one of the 4 towers on the cap. Turn the drive CCW until it is closer to #1 than any of the others. The timing is correct when the snap happens exactly as the engine reaches TDC. A little late is better than a little early.
 
Sometimes people put the wrong drive coupler on the back of the
magneto.

The correct drive will either have no markings or have the
letter"R" stamped in it.

Incorrect drive will have the letter "L" or "XR" stamped on it.

Sometimes it's easier to use the shade tree mechanic method to
time a magneto. Slap it on making sure the wires are on correct.
If it doesn't start. Take the mag off and turn the drive half a
turn backwards and reinstall. If it doesn't start, Repeat the
process turning the drive one half turn at a time. There is only
four ways the mag lugs can match up with the grooves. You should
only have to do this four times.

When everyone here ran Loaders on M's. It was almost impossible
to get to the timing marks or the spark plugs the loader was
always in the road. I used this method on many many Farmall M
tractors. Also did it a few times on Case 400 lp gas tractors
with loaders.
 
I think I finally got it close. Thank you all for your help. It tried to start once. Then it kicked back. I think I will advance it further. I may be fighting carb or other issues now.
 
(quoted from post at 14:23:30 01/31/18) Retard to avoid kickback!! Jim
Click to expand...
Thank you. I thought about that after I got back out there. I pulled my arm off and it doesn't want to go. Sputtered a few times but that's it. Might have to work on the carb and starter.
 
(quoted from post at 12:13:44 01/31/18) I think I finally got it close. Thank you all for your help. It tried to start once. Then it kicked back. I think I will advance it further. I may be fighting carb or other issues now.
Click to expand...
Not to butt in here, but I had this happen to me one time. The gear and the plastic top piece the rotor bug sits in may have spun on you. I battled and battled the same scenario then I took that darn gear out and held the teeth then turned the top plastic and the adhesive that holds them together had failed. Man I was cussin' for weeks before I figured it out!!!
 
(quoted from post at 19:48:25 01/31/18)
(quoted from post at 12:13:44 01/31/18) I think I finally got it close. Thank you all for your help. It tried to start once. Then it kicked back. I think I will advance it further. I may be fighting carb or other issues now.
Click to expand...
Not to butt in here, but I had this happen to me one time. The gear and the plastic top piece the rotor bug sits in may have spun on you. I battled and battled the same scenario then I took that darn gear out and held the teeth then turned the top plastic and the adhesive that holds them together had failed. Man I was cussin' for weeks before I figured it out!!!
Click to expand...
Thank you for your suggestion. I think it is ok but will check it again.
I think I'm having carb or vacuum problems now.
 
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