This site is not affiliated with AGCO Inc., Duluth GA., Allis-Chalmers Co., Milwaukee, WI., or any surviving or related corporate entity. All trademarks remain the property of their respective owners. All information presented herein should be considered the result of an un-moderated public forum with no responsibility for its accuracy or usability assumed by the users and sponsors of this site or any corporate entity.
The Forum Parts and Services Unofficial Allis Store Tractor Shows Serial Numbers History
Forum Home Forum Home > Other Topics > Shops, Barns, Varmints, and Trucks
  New Posts New Posts
  FAQ FAQ  Forum Search   Events   Register Register  Login Login


a coil with no resistance ??

 Post Reply Post Reply
Author
Message
steve(ill) View Drop Down
Orange Level Access
Orange Level Access
Avatar

Joined: 11 Sep 2009
Location: illinois
Points: 81240
Post Options Post Options   Thanks (0) Thanks(0)   Quote steve(ill) Quote  Post ReplyReply Direct Link To This Post Topic: a coil with no resistance ??
    Posted: 12 Oct 2024 at 3:25pm
Gots a 1990 Briggs horizontal opposed 2 cylinder 18 HP tractor.. Just rebuilt the motor after setting for several years.. Had a bad miss fire after 45 minutes and not revving up. Was going to rebuild the carb ( which i did today with good success), but though i would check for SPARK as that is simple. This has a pickup coil on the side of the flywheel so dont need a battery for ignition ( i think).... anyway, i pulled the plugs and rotated engine and had spark at both plugs... I then took my ohm meter and set for 20K and measured the plug wire to ground... NOTHING.. open circuit.. I then check the KILL wire to ground ( suppose to be a couple ohms.. and NOTHING.. open circuit...touch the meter leads together and get ZERO--OK.. I know the meter is good and i have been using one for 60 years .... Not sure how that can happen... never seen that before !

Edited by steve(ill) - 12 Oct 2024 at 3:27pm
Like them all, but love the "B"s.
Back to Top
Sponsored Links


Back to Top
DMiller View Drop Down
Orange Level Access
Orange Level Access


Joined: 14 Sep 2009
Location: Hermann, Mo
Points: 31094
Post Options Post Options   Thanks (0) Thanks(0)   Quote DMiller Quote  Post ReplyReply Direct Link To This Post Posted: 12 Oct 2024 at 3:46pm
Points open?
Back to Top
Ken Mn View Drop Down
Bronze Level
Bronze Level
Avatar

Joined: 10 Nov 2021
Location: Zumbrota Mn.
Points: 11
Post Options Post Options   Thanks (0) Thanks(0)   Quote Ken Mn Quote  Post ReplyReply Direct Link To This Post Posted: 12 Oct 2024 at 4:14pm
Try measuring the resistance from one plug wire to the other. I have a magneto for a Wisconsin motor that fires both plugs at the same time. The coil winding is not connected to ground. The Briggs may be the same.
Back to Top
steve(ill) View Drop Down
Orange Level Access
Orange Level Access
Avatar

Joined: 11 Sep 2009
Location: illinois
Points: 81240
Post Options Post Options   Thanks (0) Thanks(0)   Quote steve(ill) Quote  Post ReplyReply Direct Link To This Post Posted: 12 Oct 2024 at 4:42pm
I will try that next week Ken.. never heard of that before..no mention of anything like that on the INTERNET............. NO there are no points... some type of IMPULSE coil that just fires as the crank magnet comes around each time... imnot sure how that works.. no point, no CDI box... just that double coil and flywheel.

I worked on a weed eater and leaf blower motors last year.. they didnt have a point either.. Similar i guess... ( but they did have resistance readings !!)


Edited by steve(ill) - 12 Oct 2024 at 4:44pm
Like them all, but love the "B"s.
Back to Top
steve(ill) View Drop Down
Orange Level Access
Orange Level Access
Avatar

Joined: 11 Sep 2009
Location: illinois
Points: 81240
Post Options Post Options   Thanks (0) Thanks(0)   Quote steve(ill) Quote  Post ReplyReply Direct Link To This Post Posted: 12 Oct 2024 at 4:50pm
from BRIGGS----

When you start your lawn mower or small engine, you turn the flywheel and its magnets pass the coil (or armature). This creates a spark. The ignition system coordinates the timing so that the spark will ignite the air-fuel mixture in the combustion chamber just as it reaches maximum compression in each engine cycle- thus, maximizing the engine’s power.

Once the engine is running, the flywheel keeps rotating, the magnets keep passing the coil and the spark plug keep firing based on a specific timing.

Types of Ignition Systems

  • Solid-state systems: the more modern option, these systems use a tiny transistor in the coil or armature to close the electrical circuit that travels through the spark plug lead to the spark plug(s).
  • Breaker point systems: used on engines made before 1980, these systems use a mechanical switch instead of a transistor to close the electrical circuit used to produce a spark.
Like them all, but love the "B"s.
Back to Top
LouSWPA View Drop Down
Orange Level Access
Orange Level Access
Avatar

Joined: 11 Sep 2009
Location: Clinton, Pa
Points: 24272
Post Options Post Options   Thanks (0) Thanks(0)   Quote LouSWPA Quote  Post ReplyReply Direct Link To This Post Posted: 15 Oct 2024 at 1:45pm
Originally posted by steve(ill) steve(ill) wrote:

Gots a 1990 Briggs horizontal opposed 2 cylinder 18 HP tractor.. Just rebuilt the motor after setting for several years.. Had a bad miss fire after 45 minutes and not revving up. Was going to rebuild the carb ( which i did today with good success), but though i would check for SPARK as that is simple. This has a pickup coil on the side of the flywheel so dont need a battery for ignition ( i think).... anyway, i pulled the plugs and rotated engine and had spark at both plugs... I then took my ohm meter and set for 20K and measured the plug wire to ground... NOTHING.. open circuit.. I then check the KILL wire to ground ( suppose to be a couple ohms.. and NOTHING.. open circuit...touch the meter leads together and get ZERO--OK.. I know the meter is good and i have been using one for 60 years .... Not sure how that can happen... never seen that before ! 

I still suspect the meter! you have spark, but cannot read resistance on the coil, cannot read resistance on plug wire. Me thinks you have a funky meter, OR more likely, funky meter leads
I am still confident of this;
I will see the goodness of the Lord in the land of the living.
Wait for the Lord;
be strong and take heart and wait for the Lord. Ps 27
Back to Top
steve(ill) View Drop Down
Orange Level Access
Orange Level Access
Avatar

Joined: 11 Sep 2009
Location: illinois
Points: 81240
Post Options Post Options   Thanks (0) Thanks(0)   Quote steve(ill) Quote  Post ReplyReply Direct Link To This Post Posted: 10 Nov 2024 at 8:30am
Well, i finally got back around the checking the COIL RESISTANCE...Ken was right. Each wire measures OPEN to ground, but i have CONTINUITY between the two coil wires. Never heard of that before.. I was thinking of changing out the coil this winter ( got to pull the motor out)... but KEN saved the day!!  .... Now i know why i had NO RESISTANCE !
Like them all, but love the "B"s.
Back to Top
Les Kerf View Drop Down
Orange Level
Orange Level


Joined: 08 May 2020
Location: Idaho
Points: 783
Post Options Post Options   Thanks (0) Thanks(0)   Quote Les Kerf Quote  Post ReplyReply Direct Link To This Post Posted: 10 Nov 2024 at 4:31pm
Originally posted by steve(ill) steve(ill) wrote:

Well, i finally got back around the checking the COIL RESISTANCE...Ken was right. Each wire measures OPEN to ground, but i have CONTINUITY between the two coil wires. Never heard of that before.. I was thinking of changing out the coil this winter ( got to pull the motor out)... but KEN saved the day!!  .... Now i know why i had NO RESISTANCE !

Yup, Onan twins are the same; they fire both plugs at once. Quite a few modern automotive work this way too, they fire plugs in pairs. One of the low-budget hacks for bad Onan'$ coil$ is to use a GM coil.
Back to Top
 Post Reply Post Reply
  Share Topic   

Forum Jump Forum Permissions View Drop Down

Forum Software by Web Wiz Forums® version 11.10
Copyright ©2001-2017 Web Wiz Ltd.

This page was generated in 0.063 seconds.


Help Support the
Unofficial Allis Forum