(800) 853-2651
SHOP NOW

M-No fire to Plugs

L

LouieCanova

New User
Friend trying to get his M running. He has fire to distributor points but none out to plugs. Wire from coil to points gets hot and will smoke and wire to ignition switch gets hot too. How much voltage should be leaving coil to points? Is coil bad, condenser bad, any ideas?
 
Wire to the points should NOT be getting hot ! there must be a short somewhere, maybe a bad condenser, maybe point grounded.
 
And should only be +or- 6 volts to points from coil. The points are only a switch to allow high voltage from coil through distributor rotor and cap .
 
You/he has a dead short some place in the system. I would pull the distributor wire off the coil the one going to the points and see if the ignition wire still gets hot. If it does then the coil is shorted which does happen. If it no longer gets hot then you have a short in the distributor some place
 
With respect, the points control much lower voltage in the primary circuit, 12v in the 12v system, or 6v in 6v systems, plus minor surges from collapsing coil field magnetism of a few hundred volts. They open triggering that collapse.
Jim
 
I agree with Old and Allan, a coil should have 2.5 ohms if 6v, or 4.5 or so ohms if 12v. Less than one ohm is shorted. If the wires are on both coil terminals correctly, the coil is likely the problem because the points are supposed to be grounded, and the ignition switch side is supposed to have supply voltage. Jim
 
That's what I was trying to say. Isn't the purpose of the ballast resistor or internal resistance in the coil to keep the point voltage around 6 volts and the bypass wire to give higher volts for starting?
 
I'd look for trouble where the primary wire enters the distributor housing. The bolt/stud through the dist. case is supposed to be insulated from the dist. housing.
 
I agree that could be an issue, but he states the wire gets hot. It would not get just as hot if that was grounded. The coil would heat, and there would be no spark, but the wires should be fine. Jim
 
Yes. There are no internal resistors in coils that I am aware of, just more and smaller wire that increases the resistance in a true 12volt no external resistor coil. Jim
 
You must log in or register to reply here.

Similar threads

C
Electrical problem with my Cub 184 tractor
Replies
15
Views
283
John T
J
O
630 ignition issues
Replies
4
Views
423
PJH
P
D
Stumped - no spark
Replies
12
Views
600
DD in WA
D
M
M has no spark
Replies
11
Views
531
used red MN
U
G
help with no fire to points ford8n
Replies
5
Views
482
JMOR
J
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