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Magneto timing on H

A

Anonymous-0

Well-known Member
Have spent the better part of an afternoon trying to time magneto on my H project. Best I've been able to do is to get the mag to trip BETWEEN the two marks on the pulley, not right on the first mark. Also, the top of the mag is adjusted AWAY from the tractor as far as it will go. Will it be satisfactory as is, or should I keep trying? I think I'm missing something here but am not sure what it is.
 
The position of the mag where its bolted makes no difference. You need to remove #1 plug get that cycl on compression and not exhaust as the piston will be at the top on both cycles you need to make sure its on compression that means BOTH valves are closed. Then make sure the rotor is lined up with the tower when it snaps and you are in time there is no advance on that mag till engine is running as it starts on TDC. iF THE ROTOR ISNT LINED UP WITH #1 TOWER you need to remove the plate and get the rotor lined up. Easy way to check is remove all plugs and the cap have someone hit the starter sw and with the mag cap off you will see the rotor line up and snap make a mark on the body of the mag where #1 wire goes and that would be around the 1 oclock position then with your finger over the hole when the engine is spun over you will feel compression and watch the rotor snap.
 
to get timing fine tuned to the mark, you need to: line up the pully to mark turning engine the way it rotates. put a piece of paper in between the points. then loosen the two mag bolts and turn mag opposite from normal rotation,may need to rock back and forth first but turn mag opposite of rotor rotation to set timing.as soon as you can pull paper from points you are statically timed. if run out of mag travel your one cog off on gear, so need to remove mag and reposition gear accordingly.
 
Turning the top of the mag towards the engine will advance the timing. The magneto turns clockwise,so turning it counter clockwise will advance the timing. Joe
 
It should snap on the secind mark. Retard it towards the block until it does. First mark is for advanced timing.
 
If it trips between the two marks that are right close together that will work just fine. The first mark is top dead center, second one is 5 degrees after top dead center. Might be number one or number four. The thing you do not want is for it to trip any before the first mark or you can get a kick back, arm breaker they call it. Yaa , I know hold the crank correctly and you can avoid the broken arm also. The magneto has a 35 degree lag. In other words, when engine is running you have 35 degrees spark advance from the spot it trips at. Any minor adjustment you make between that top dead center mark and the 5 degree atdc mark will not be detectable when engine is running. There is another mark all by it's self for greasing pilot bearing in the flywheel but I assume you are not talking about that one and it is a long ways from the other two.
 
Thanks everybody for your info. I think I've got it right now...mag tripping about 2 degrees after TDC.
I have adjustment room to retard it a little if necessary. Now add some fuel and give er a try.
 
I would advance it the 2 degrees and have it trip on TDC. I do not believe you want it to trip ATDC.
 
Guess I must have a rare H, took the cap off and it turns clockwise making the firing order
2 1
4 3 Joe
 
I'd say definitely keep it 2 degrees after tdc.

It's a safety issue in case you ever need to hand crank it.

In these old slow low compression engines, you won't notice any performance difference from a few degrees.

If you go TOO far past tdc, it'll be tougher to start - but 2 degrees isn't too far.
 
Depends on which end you are looking at but there are 2 gears in there that reverse the rotor rotation from the drive rotation.
 
meant to mention - remember that firing 2 degrees after tdc is only on startup.

Once the engine starts and the magneto is at speed - it'll switch over to it's advance setting - probably around 35 degrees. (subtract from that the 2 degrees - but that's fine)
 
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