(800) 853-2651
SHOP NOW

J 4 magneto question

J

jsfarmall

Member
I never fooled with a mag. A project cub I recently acquired it has a mag and no starter. So my idea is to leave it hand start with the mag and not use a battery. How do I test the magneto without it on the engine? The engine is currently in pieces on my workshop floor lol.
 
Well, you could do like I did years ago. I clamped the mag in a vice, put a spark plug wire in it and told a (friend) of mine to hold the end of the wire and put one hand on the vice. The mag only had to snap once for me to know it worked. Poor guy hasn't trusted me since.
 
You have learned one way to find if it hurts, but to find if it will fire a spark plug, clamp it in a vice, and connect a wire and spark plug to the coil cap.and ground the plug to the magneto body. put a ratchet and socket on the nut that holds the impulse and turn it till it trips. If you get a good hot spark you know the points, condenser, coil, and impulse are all good. Note, if it has been setting an extended period the points may need filed or replaced, and coil may also be weak. Coils are expensive.

Once you have good spark from the coil cap, connect wire back to distributor cap and use plug wires and spark plugs to see if it fires the plugs in order 1-3-4-2. There is not a spark safety gap built into the J4 or H4 mags, so it is not recommended to trip them without someplace for the spark to go.
 
You must log in or register to reply here.

Similar threads

D
12 volt Conversion WITH Magneto Farmall A HELP
2
Replies
21
Views
825
Jim Becker
J
I
42 H Magneto question
Replies
5
Views
390
buckeye al
B
T
Magneto replacement
Replies
8
Views
463
tomturkey
T
3
farmall M magneto question
Replies
8
Views
627
Jim Becker
J
P
Cub starter question
2
Replies
27
Views
819
560Dennis
560Dennis
Tractor Parts Tractor Manuals

We sell tractor parts! We have the parts you need to repair your tractor - the right parts. Our low prices and years of research make us your best choice when you need parts. Shop Online Today.

Copyright © 1997-2024 Yesterday's Tractor Co.

All Rights Reserved. Reproduction of any part of this website, including design and content, without written permission is strictly prohibited. Trade Marks and Trade Names contained and used in this Website are those of others, and are used in this Website in a descriptive sense to refer to the products of others. Use of this Web site constitutes acceptance of our User Agreement and Privacy Policy TRADEMARK DISCLAIMER: Tradenames and Trademarks referred to within Yesterday's Tractor Co. products and within the Yesterday's Tractor Co. websites are the property of their respective trademark holders. None of these trademark holders are affiliated with Yesterday's Tractor Co., our products, or our website nor are we sponsored by them. John Deere and its logos are the registered trademarks of the John Deere Corporation. Agco, Agco Allis, White, Massey Ferguson and their logos are the registered trademarks of AGCO Corporation. Case, Case-IH, Farmall, International Harvester, New Holland and their logos are registered trademarks of CNH Global N.V.

Yesterday's Tractors - Antique Tractor Headquarters
Website Accessibility Policy

Back
Top