Sloppy day

[chet]

Is that an early 8n with front mount dist or later with side mount. If it is side mount, is da round can coil you installed internally resisted or not. I'm not positive but pretty sure all the 12 volt top mount coils are externally resisted.

[Tacotodd]

Yeah, if you run no-resistor coil, you’ll need a resistor wire in your system. The coils I sold told you on the coil themselves if they were or not. 

The more I think on it with my personal experience, fuel related. 

Like a chainsaw, filter, lines. Most likely something basic and small. The stuff that drives you crazy!

How’s your voltage resistance on the wires?

[Jeff]

It is a very old coil. Most likely, non resisted. Fuel is good. Changed the condenser,  the points look okay. It us now backfiring if I try to throttle up. Starts instantly , sits and idles nice.

[Magicman]

My old 12 volt Ford cars had resistors.  They cranked on 12v and ran (through the resistor) on 6v.  If it cranked and then died immediately when you released the key, you knew that the resistor was open.

[Tacotodd]

Use a 12V internal resistor coil and be done with that part, it won’t hurt.

[A-z farmer]

Jeff 
On those  6 volt 8n ignition systems seem to get burned up by 12 volts .I put a resistor before the coil but mine is the front mount square coil.It seems those tractors run forever but I have had to replace points ,plugs and condenser many times over the years.Good luck 

[Corley5]

Throw the points and condenser away and switch it over to electronic. 

[Magicman]

Yup:  LINK

[WmFritz]

Now I'm thinking I should convert mine. She always starts, but for that first crank or two it's sounds iffy...Especially in the winter. 

[hedgerow]

Yup:  LINK

This makes a nice set up on the old tractors. I have one on a 3010 JD that's been on it for thirty years or so. If you add a resistor ahead of the coil the back firing will stop. Some will run ok with 12v to the coil and some won't . 

[Jeff]

This is madness.  New internally resisted coil. Same issue. Starts, wont run right.  Unhook the alternator,  

Put the included resistor in, it wont fire and start. Jump the resistor,  it starts, runs and backfires. remove the jumper from the resister, it sits there and runs and apparently charges fine. So it runs on the resistor but it won't start on the resistor.

[Don P]

I think Ford's and Dodges, maybe everything  , starts on 12 and runs on 6.

[Corley5]

We put the same 12v conversion kit on our late model side distributor 8N this fall.  We also installed a 12v negative ground Pertronix ignition.  I opted out of their brand coil and went with an internal resistor model from Car Quest and carbon plug wires and new Autolite plugs.  Started right up after we did a valve job too

[Don P]

Here's what I'm remembering;
 

 

[Jeff]

8n has a 3 pole solenoid. 

[Corley5]

I'll have to look at mine.  We did away with the starter mounted solenoid and put one on the "firewall" by the battery.  I don't how many terminals it has   

[Gary_C]

Jeff, I have been thru the same kind of issues with my IH 574 gas tractor. It's not running now because of engine and valve issues (it needs an overhaul) but in the fall going into winter it would not start nor run right and I would try every combination of coil with and without resistor. In the end I would find that the plugs were fouled some way and a new set of plugs would cure the problem. I think the problem may have to do with the seasonal change in the gas formulation from summer gas to fall gas and then to winter gas. The summer gas is less volatile to slow evaporation and apparently it does not burn as well in cold temps and will foul your plugs even though they don't look bad. So try fresh winter gas and new plugs.

Also many of those older tractors need a change in heat range of the plugs from original for todays gas. 

[Don P]

8n has a 3 pole solenoid.

That 4 pole is cheap and will do what you have been jumpering. The ignition switch run position goes to a non resistor coil through the in line resistor, the I post on the ford solenoid also goes to the same post on the coil but shoots it 12V in the crank position.

The 6 volt was I think to cut down on distributor cap wear and arcing, it might be worth checking the condition of those parts.

[Jeff]

I am beginning to think the alternator is the culprit.  I have been through everything. The only real thing you need to do to make the tractor run right is disconnect the alternator. It then runs fine, starts fine.   I unhooked the wire going from the one wire alternator to the amp meter, and there is over 30volts coming out of the alternator. the meter is correct. It reads 12 coming from the battery.  

[Don P]

Hook it back up and check the voltage across the battery terminals both before starting and with it running. You should see an increase of a couple of volts with it running. I think spinning it open circuit it goes wild until it lets the magic smoke out. Or take it off and take it into an auto parts that can hook it up and test it.