6v coil w/internal resistor

equeen · Oct 2, 2012

8N Side mount distributor.

With ignition switch on, power to - post on coil and no wire/cable connected from coil to distributor, coil has approx 6 volts on - post, on + post and on center "post".

Is this information of any value to me? What does it tell me?

Then, with connections to the distributor, I get essentially no voltage reading at the post to the distributor. Bump the starter a number of times, still no reading. Bushing and insulator of distributor post appear okay. Points set at .025.

souNdguy · Oct 2, 2012

i doubt you when you say 6v w/ internal resistor.

in any case.. open circuit just tells you there is some basiv continuity. after hooking up dizzy then 0 reading menas points are closed.. or that line is shorted to ground.. either at points or insulator or copper strip.. or in the breaker plate.

post back

equeen · Oct 2, 2012

You are a wise man to doubt my statement. I should have been specific. Coil is stamped "Use Without External Resistor".

souNdguy · Oct 2, 2012

pretty much what I figured. round coils are generally in the 6v variety or 12v.. whish is actually really just an indication of how much primary resistance they have. a '12v' coil that says use with external resistor is generally JUST a 6v coil.. etc..

equeen · Oct 2, 2012

Okay, it's dark outside.

+ side of coil wired to side of distr (wire is good)

cover off distr, points exposed

someone pushed starter button while I looked in the dark into the points/distr.

not even a glimmer of a spark as points opened and closed.

So, something is grounding in there??

souNdguy · Oct 2, 2012

and it would be upstream of the points.. like the copper conductor.. or the condensor.. or the feedthru insulator.

ps.. if you are negative ground.. the (-) side of the coil goes to dizzy... ( won't make a bit of difference tho.. )

old · Oct 2, 2012

Easy test here. Pull the ignition side wire off the coil. Turn on the ignition. Touch the wire to the coil while holding the coil wire as in the center wire of the cap close to the block. Be sure to have the points open. If when you do that you get a spark you have a short in the distributor be it the insulator or other such thing but you have a short. If no spark then close the points and try again. If no spark with the points closed then the points are bad or need to be cleaned

souNdguy · Oct 2, 2012

good post.

that's a real easy test for someone who may not understand the in's and outs of ignition or electronics. real simple and easy to see.

good post.

equeen · Oct 2, 2012

Ignition on
Points OPEN
+ wire to distr
ignition wire touched to - coil post
coil center wire to bare metal and finger

= shock, ouch, spark

Ignition on
Points CLOSED
+ wire to distr
ignition wire touched to - coil post
coil center wire to bare metal and finger

= shock, ouch, spark

Royse · Oct 2, 2012

(quoted from post at 22:17:49 10/02/12) Ignition on
Points OPEN
+ wire to distr
ignition wire touched to - coil post
coil center wire to bare metal and finger

= shock, ouch, spark

Ignition on
Points CLOSED
+ wire to distr
ignition wire touched to - coil post
coil center wire to bare metal and finger

= shock, ouch, spark

LOL Maybe Old left that little detail out?
Good blue/white spark?

equeen · Oct 2, 2012

Okay, as to the spark, maybe I was seeing things as I got the shocks; so I'll try again tomorrow.

However, this is an absolute, I just went outside and did it:
With points open or closed, with + post attached to side post on distr and with center coil wire touching nothing - I DO get a slight spark when rub ignition wire against - post on coil.

What does this mean?

Royse · Oct 2, 2012

(quoted from post at 22:46:31 10/02/12) Okay, as to the spark, maybe I was seeing things as I got the shocks; so I'll try again tomorrow.

However, this is an absolute, I just went outside and did it:
With points open or closed, with + post attached to side post on distr and with center coil wire touching nothing - I DO get a slight spark when rub ignition wire against - post on coil.

What does this mean?

If you get a spark with the points open you have a ground or partial ground
somewhere in the distributor as Old said.
Hold the wire with spark plug pliers, a leather welding glove or something
electrically insulating (wood, plastic, etc) to keep from getting a shock.

old · Oct 3, 2012

You get a spark with the points open and also closed means you have a short in the distributor some place. Maybe the insulator going in the side of the distributor or you have the condenser wire hitting some metal some place or the points them self have a short in them or around them

old · Oct 3, 2012

Nope did not leave it out since in this case it does not matter. Getting a spark with the points open means he has a short in the distributor some place and that is the problem blue/white spark in this case if not needed till the short is found and fixed

old · Oct 3, 2012

I use that test when ever I pick up a non-running tractor to see if the points need to be messed with or if I can go on to other problems. Takes less then 5 minutes and 99% of the time it tells a person if the points are good or if they are bad and any body can do it

equeen · Oct 3, 2012

Replaced points and condenser and get voltage when I should and do not get voltage when I should not.

Removed and cleaned some crud off breaker plate. Noticed that about 1/2 of the copper primary conductor from side of distr to points is broken. Insulator and bushing appear to be okay - but will be replacing all.

Thanks to everyone for all your help. Print-outs and notes go into my 8N tractor file.

Oops, tractor still doesn't run. Spark to two plugs I checked and poured some gas in the cylinder - but no "explosion". Probably will take the unit to a tractor doctor since it's still sitting on the trailer and I'm tired.

Dell (WA) · Oct 3, 2012

queenie........you ask......"With ignition switch on, power to - post on coil and no wire/cable connected from coil to distributor, coil has approx 6 volts on - post, on + post and on center "post". Is this information of any value to me? What does it tell me?"........yer roundcan coil is an "auto-transformer" ........meaning ALL windings are somehow hooked together. Yer primary winding (for the points) is in the 130-ohm range (Ohms is technical unit of resistance) and the secondary winding (fer the sparkies) is about 4000-ohms. Surprizingly enuff, even yer fancy digital ohm-meter can NOT eazily tell the difference between 4000-ohms ...or... 4130-ohms when measuring between either side terminal and center terminal. More importantly, you have CONTINUITY (ohms) between enny of the 2-terminals you choose to connect to. It should be intuitively obvious, an OPEN (no continuity) reading is a BAD coil. ........Dell, retired Electronics Engr

old · Oct 3, 2012

Spark at only 2 mean either you do not have the points set at 0.025 like you should or the distributor bushings are going bad or the cap and or rotor is bad. Easy way to make sure it is not the bushings is check the gap at all 4 lobes of the distributor and make sure they are all at 0.025 or very close

equeen · Oct 3, 2012

Thanks for the additional info, Old.

I only checked two plugs. Don't know what was going on in the other two.

Fun time mowing this afternoon; so back to work on brother's 8N tomorrow since tractor doctor can't see it till next week.

New rotor. Temporarily took cap off a fine running tractor to test and no difference.

Hmmm? Yellow spark at the two plugs I checked. Perhaps I shall temporarily swap plug wires from other tractor and check all 4 cyls for blue spark??

Royse · Oct 3, 2012

Hmmm? Yellow spark at the two plugs I checked. Perhaps I shall temporarily swap plug wires from other tractor and check all 4 cyls for blue spark??

Could be plug wires, specially if you're testing at the wire and not watching the plug.
With all the cranking you've had to do for testing, I wouldn't be a bit surprised
if the plugs were fouled out with gas too. I'd clean them off with a propane torch.
Another thought, since you've had to re-check the point gap make sure you clean
those off too. They may have gotten oil from the feeler gauge.

old · Oct 3, 2012

Are the plugs auto lite 437s??? If not try a set of them right up front since a lot of times spark at the plugs not being blue/white is a bad plug. Now if you checked spark at the wires and it is a blue white and jumps a 1/4 inch gap you know it is the plug if it is yellow then recheck the point gap and make sure the points are good and clean and all connections are clean tight and bright

equeen · Oct 3, 2012

Will follow your instructions.

Also:

The plugs are good 437s. However, I shall replace them with some 437s that have about 1 hour of runtime.

As to the spark; I checked at the plug, not the plug wire.

old · Oct 3, 2012

Ya you have to check both at the plug and the plug wire since if good one place and not the other then you got a bad plug and now days bad parts seem to be very common

36 Coupe · Oct 18, 2012

Dufus thinks that means there is a resistor inside the coil.No room in the coil for a resistor.

6v coil w/internal resistor

Member

Well-known Member

Member

Well-known Member

Member

Well-known Member

Well-known Member

Well-known Member

Member

Well-known Member

Member

Well-known Member

Well-known Member

Well-known Member

Well-known Member

Member

Well-known Member

Well-known Member

Member

Well-known Member

Well-known Member

Member

Well-known Member

Well-known Member

Similar threads