How to Time Magneto on an A

jamieei · Jul 20, 2009

This message is a reply to an archived post by Piratefan on March 17, 2009 at 17:30:19.
The original subject was "How to Time Magneto on an A".

does anyone know if the two brass gears on the cap side of the H4 mag have timing marks... the two gears that drive the rotor that is. I dropped one out when I opened it up about a month ago and had a heck of a time getting it timed close enough to start the thing. I replaced the condensor with a new one and the spark went from blue to kinda white. Is this the timing of the spark maybe or just a bad condensor? The condensor in the mag was kinda gold colored so I assume its the orig or quite old. Any tips on getting it set back up correctly?

Bob · Jul 21, 2009

For Pete's sakes, no need to "re-invent the wheel"... just go to the link below and peruse the original factory mag manual and see how to time the gears!

http://www.cleancomputes.com/Cub/Blue%20Ribbon%20Service%20Manuals/GSS-5035%20Service%20Manual%20Magnetos/index.html
F 4

gene bender · Jul 21, 2009

Just make sure when you turn the mag to impulse that the rotor is lined up with the tower. 31 position is 1 oclock. You should take all plugs out then take #1 plug wire and put on a plug clamp the plug to the steering shaft.This gives you hands free. Put your finger over the #1 hole and enguage the starter watch the spark when #1 IS ON COMPRESSION. let the engine turn over several times. IF you get the mag in wrong you can only be off 180 degrees as the slot on the timing gear will only let the mag hook up two ways either you are in time or off 180.

jamieei · Jul 21, 2009

I was thinking that if those two tiny little brass gears that turn the rotor were off a couple notches that the timing would end up being off a couple degrees. When it's timed "right", my mag leans out away from the engine more than I think it should.

Szrachnor · Jul 21, 2009

Yes, the 2 gears have marks and they have to be lined up. The larger gear has an "R" and an "L" marked on it. Since this is a right hand magneto, time the smaller gear to the "R". Here is something else to consider, if you magneto doesn't trip when #1 cylinder is at or close to top dead center than someone probably didn't time the governor properly to the camshaft gear.

-Leon

gene bender · Jul 21, 2009

You can take the cap off then turn the engine over with the crank just before it trips the rotor should line up with the tower.

Owen Aaland · Jul 21, 2009

(quoted from post at 06:42:58 07/21/09) Yes, the 2 gears have marks and they have to be lined up. The larger gear has an "R" and an "L" marked on it. Since this is a right hand magneto, time the smaller gear to the "R". Here is something else to consider, if you magneto doesn't trip when #1 cylinder is at or close to top dead center than someone probably didn't time the governor properly to the camshaft gear.

-Leon

The smaller gear has one tooth that has a bevel on it. It is the tooth that you line up with the "R".

Szrachnor · Jul 21, 2009

The smaller gear has one tooth that has a bevel on it. It is the tooth that you line up with the "R".

Thanks Owen, looks like I forgot that little detail.

How to Time Magneto on an A

jamieei

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Bob

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gene bender

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jamieei

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Szrachnor

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gene bender

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Owen Aaland

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Szrachnor

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