801 No spark

[cajee1963]

Like the title says, I have an 801 that isn't making spark.

I have a question about the ballast resistor between the source and coil.
It is reading 12 volts on both sides of the resistor when its not attached to the coil. It will read 12.75 or 5.5 when power is connected to the coil. I am guessing the difference depends on whether or not the contacts in distributor are closed or not?

So my first question...is the purpose of the resistor to drop the voltage to 6? Is the resistor the " 12 volt conversion"?
and the tractor has power at the coil, does that mean the problem is in the distributor? The coil is new so that shouldn't be the issue.
Thanks for any help

PS. Do 801s have neutral switches, other than the button starter by the gear shifter?

 

[old]

Good chance the points need to be cleaned or replaced gap is 0.025

 

[Andy Wickiser]

Is the new coil a 6 Volt coil or a 12 Volt
coil? If it's a true 12 Volt coil you
don't need a ballast resistor. If it's a
6 Volt coil or one labelled 6 or 12 then
you do need a ballast resistor. A 6 Volt
or 6/12 coil Will have a primary
resistance of around 1.5 ohms, a 12 Volt
coil around 3 ohms. Warning: digital
meters can be flakey when measuring
resistance that low, no zeroing mechanism,
you must factor in the reading when probes
are shorted (offset).

 

[Sean in PA]

I have a question about the ballast resistor between the source and coil.
It is reading 12 volts on both sides of the resistor when its not attached to the coil. It will read 12.75 or 5.5 when power is connected to the coil. I am guessing the difference depends on whether or not the contacts in distributor are closed or not?

Correct.

So my first question...is the purpose of the resistor to drop the voltage to 6? Is the resistor the " 12 volt conversion"?

Those are your second and third questions. I answered your first one above (at least it had a question mark at the end even though it wasn't quite worded as a question). That tractor came with a 6 volt system from the factory and did not use a ballast resistor, If it was converted to a 12 volt system, that was most likely done by replacing the generator, external voltage regular and battery with a 12 volt alternator and battery. If the coil was not replaced at the time that the 12 volt conversion was done, then the ballast resistor is needed to limit the current so that the points would not burn out in short order,. A side effect of the ballast resistor limiting the current is the drop in voltage across the resistor when the points are closed.

As to why you are not getting spark now, there could be a number of different reasons. What is the history of the tractor? Is it new to you and has'nt made a spark since you got it, or was it working for some time for you and then stopped?

 

[cajee1963]

Thanks Andy

The coil has a " must be used with a resistor" printed on the side so I think it is a 6 volt coil.
This is a live and learn thing, but if had I known yesterday that a 12 volt coil could be used without the resistor in place of what is on the tractor it, I would saved a few $$

Thanks for responding

 

[cajee1963]

You're right Sean I didn't have an accurate count.

I was using this tractor last week.
I took the battery out to charge it and after it was put back in the tractor wouldn't start.
My first thought was that something came loose in the removal or installation of the battery, but the battery side of the coil reads 12 volts with the key on and 0 with the key off.
The coincidence of the battery removal and no start has me unsure, I want to think they are related but can't see how they would be.

This post was edited by cajee1963 on 06/12/2021 at 07:44 am.

 

[Andy Wickiser]

The readings you gave are correct for a 6
V coil on a 12 V system with resistor and
show that your points are probably
working. How are you checking for spark?
Are you sure it's not there? How about
spark out of the coil tower (before
distributor cap)? If spark there but not
at the plugs then wire between coil and
cap, cap, or rotor. If no spark out of
coil tower then perhaps condenser or
condenser connections loose.

I've also had cases where I thought it was
ignition but actually fuel - flooded from
trying to start, or not getting fuel to
engine's intake.

Sorry I can't be more definitive, you have
to trace, trace, trace right down the line
until the engine comes to life.

 

[cajee1963]

(reply to post at 10:10:01 06/12/21)

The readings you gave are correct for a 6
V coil on a 12 V system with resistor and
show that your points are probably
working

That phrase alone is worth the price of admission. Thanks for pointing that out for me. I know would have ended up replacing the points
I tested for spark by removing a plug and holding on and near the block while cranking the motor. lol, I don't know another way

It will likely be Monday, but I'll start at the coil as you suggested and chase the spark out to the plug.
Its a propane tractor and I've had a heavy propane smell when I try and start it. Thought about it being flooded, (that still might end up being the problem I guess) . But the lack of spark moved me past thinking about the flooding
Thanks

 

[Andy Wickiser]

Hmm, interesting it's propane, I don't
think you can flood those. Anyway some
people troubleshoot by opening and closing
the points manually with a thin plastic
stick or such and watching for little
sparks at the points and spark out of the
coil secondary (ignition on but you don't
have to run the starter). With points
exposed you can also check for low
resistance to ground when points are
closed (voltage at coil-to-distributor
terminal on coil should drop to zero with
points closed and show battery voltage
with points open). Good luck chasing down
the problem.

 

[jimtrs]

I tested for spark by removing a plug and holding on and near the block while cranking the motor. lol, I don't know another way....

Leave your plug in, to assure proper gronding. Use a tester like this. Open it up to 3/16 or 1/4 inch. If the spark jumps that, you have a good, and strong spark.

 

[Jim L WA]

Hope you find your problem soon. When checking for spark with a spark plug, you need to hold the plug in a good clean spot on the block not near the block.
Just to clear things up a bit, that is not a ballast resister. It's just a voltage drop resister. A ballast resister is a used to allow for a hotter spark during cranking and then it gets hot and reduces the voltage to a coil. They were used on the front mount Fords not just tractors.

 

[Sean in PA]

(quoted from post at 20:06:51 06/12/21) Hope you find your problem soon. When checking for spark with a spark plug, you need to hold the plug in a good clean spot on the block not near the block.
Just to clear things up a bit, that is not a ballast resister. It's just a voltage drop resister. A ballast resister is a used to allow for a hotter spark during cranking and then it gets hot and reduces the voltage to a coil. They were used on the front mount Fords not just tractors.

A ballast resistor and a "voltage drop resistor" are the same thing. Having it wired so that the coil gets the full 12 volts while starting is the result of a bypass wire and has nothing to do with the resistor itself other than if you have a true 12 volt coil that doesn't use an external resistor, then there is no possibility for a bypass wire because the coil is getting the full 12 volts all of the time. Mid to late 60's Mopar engines used a ballast resistor and a bypass wire. I had a boat with an Oldsmobile 455 V-8 that used a ballast resistor but didn't have the bypass wire. The resistor that was installed on the boat when I bought it was a Mopar ballast resistor. I added a bypass wire to allow the full 12 volts to get to the coil during starting and it made it a whole lot easier to start.

 

[cajee1963]

Thank all of you for responding.
I've learned a lot from your comments.
Unfortunately the tractor still isn't starting, I'll be looking at it today and hopefully get the issue resolved.

 

[cajee1963]

(quoted from post at 17:06:51 06/12/21) Hope you find your problem soon. When checking for spark with a spark plug, you need to hold the plug in a good clean spot on the block not near the block.
Just to clear things up a bit, that is not a ballast resister. It's just a voltage drop resister. A ballast resister is a used to allow for a hotter spark during cranking and then it gets hot and reduces the voltage to a coil. They were used on the front mount Fords not just tractors.

I appreciate the need for uniform terminology. Not being a mechanic myself, I only repeat what I read or hear. The resistor was referred to as ballast resistor from more than one online resource. Voltage drop resistor seems more descriptive for sure.
Thanks for the input.

This post was edited by cajee1963 on 06/22/2021 at 09:19 am.

 

[cajee1963]

Ended up replacing the points and condenser.
The tractor started as soon as the motor started turning.
Thanks again for your help

 

[Sean in PA]

Thanks for following up with your solution. It's helpful to others who might have the same problem in the future if they search the archives of the site for their problem.