F20 mag timming

85 Bishop · Jan 14, 2017

What are the correct steps in timmming the mag on a F20 ? What is the reason for the wire put in the oil cap ? Thanks

teddy52food · Jan 14, 2017

What model Mag? They all are timed to impulse at TDC or a few degrees after especially if you are hand cranking it.

SW EM · Jan 14, 2017

"Wire put in oil cap"......

I don't understand exactly what you mean. There are a couple of places on the magneto were a cap can be flipped and a few drops of oil added for bearings.

To time it, have the #1 plug wire fire a spark just after TDC of cyinder 1's compression stroke. If you have the valve cover off and take out the spark plug this can be easily verified. The coupler between the mag fastens to has multiple slots which can be used to fine tune the timing.

When I restored my first F-20, I just bolted down my magneto on checked the timing and it was absolutely spot on! It's been over 5 years and I haven't had luck like that since....

85 Bishop · Jan 14, 2017

I have top center # 1 , have mag at # 1 plug on cap , Some where I read about putting a wire in the oiler near the drive end of the mag to disengage the impulse trip ! I think I had a picture also but miss placed it ! It sat for 30 years in a barn, had the mag rebuilt and put it back on just as it was. I have advanced it and its better but not right yet. So should start over . May be F4 mag ! Thanks.

Oldiron29 · Jan 14, 2017

In the manual I believe they say small nail in oil hole will lift the impulse so you
can turn the mag without the spring causing alignment pressure. This would be on IH F-4
mag. Rough timing should be set TDC #1 than adjust from there as needed.

36F30 · Jan 14, 2017

(quoted from post at 16:43:55 01/14/17) What are the correct steps in timmming the mag on a F20 ? What is the reason for the wire put in the oil cap ? Thanks

The wire in the oil cap is to disengage the impulse so you can set the timing. This is where unless you've done these before you need to follow the book, one bad piece of advice can bust your arm or your head.

36F30 · Jan 14, 2017

Sorry the pages are out of order, can't edit on this antique software here.

85 Bishop · Jan 15, 2017

Thanks for the help ! I have installed a electric starter to save my arm !

steelfronts · Jan 15, 2017

Bishop if you have electric start the impulse must still work (click) while its cranking or timing may be too far advanced to start.

85 Bishop · Jan 15, 2017

Yes it has worked right along , I start it with it retarded just like you would when hand cranking ( or it would be hard on the starter ) . It was in a barn for 30 + years and after repairing the mag I put it back like it was ! Well it was way off and had to time it from scratch. Now seems to run good . Next is to put the radiator back together and on the F20 and get some time on the engine . If any one is interested in my starter set up just ask . Thanks .

Billyboyr66 · Jan 16, 2017

(quoted from post at 19:55:15 01/15/17) Yes it has worked right along , I start it with it retarded just like you would when hand cranking ( or it would be hard on the starter ) . It was in a barn for 30 + years and after repairing the mag I put it back like it was ! Well it was way off and had to time it from scratch. Now seems to run good . Next is to put the radiator back together and on the F20 and get some time on the engine . If any one is interested in my starter set up just ask . Thanks .

I'll bite, what kind of starter setup do you have?

85 Bishop · Jan 16, 2017

Mid 80'S Chevy V8 auto flex plate bolted to joint ahead of transmission . GM mid 90'S starter (planetary drive type ) short to fit behind bellhousing . I would need email to send picture. Mike.

F20 mag timming

85 Bishop

New User

teddy52food

Well-known Member

SW EM

Member

85 Bishop

New User

Oldiron29

Well-known Member

36F30

Member

36F30

Member

85 Bishop

New User

steelfronts

Member

85 Bishop

New User

Billyboyr66

Member

85 Bishop

New User

Similar threads