Spark Problem with 1947 Ford 8N

[HowardH]

Hello fellow old tractor owners,

I bought a 1947 8n (the year I was born) from a guy with a w3 loader which was disconnected.
Last year I used the 8N for some grading work and shut it down for the winter.

When I tried to start it this spring, it would not start. I pulled a plug and checked the spark and it look like it had spark. These are the things I've done since then:

1. The float was sticking on the carb, so I pulled it and tore it apart and cleaned it out and checked the settings.
   1. the 8n still did not start
2. I bought a new carb
   1. Still did not start
3. Pull the distributor (front mount, 6 volt)
   1. Put new points and condenser in and set the gap (.015) and the timing (straight edge.)
   2. Replaced the cap
   3. Replaced the coil The old one had a lower resistance than the one show in a YouTube video. The new was was the same as the video.
   4. Still did not start.
4. I put a multimeter on the coil post and measured the voltage,
   1. ...151.jpg shows the voltage with closed points,
   2. ...226.jpg shows the voltage with the points open.
5. I put my old coil back on and measured the voltage with closed points again
   1. …424 shows the voltage with my old coil with points closed.

This old farts brain is stumped, but I know one of you folks out there knows what is wrong.

Any HELP???

The high desert Septuagenarian

 

[Non-farmer]

Hi Howard, and welcome to YT

I don't have the answer to your question. I'd only suggest that you not take for granted that everything on youtube is right

PS: I'd have said hi earlier, but i was out getting some seat time on my 1947 2N

 

[6 SLY PLACE]

Maybe the spark plugs are too wet with gasoline

 

[Btzj02]

Now that you have done all that work go back and test for gasoline flow to the carb by doing the drain down test and check the spark again across a 1/4" gap. A "new carb" could mean almost anything but it seems that even the poor quality carbs will allow the engine to start assuming you have good gasoline flow to the carb. If spark jumps 1/4 inch I would inspect and clean/replace the plugs. I have never set the timing on a front mount distributor but timing is the next thing I would verify along with firing order 1,2,4,3.

 

[HowardH]

Hello fellow old tractor owners,

I bought a 1947 8n (the year I was born) from a guy with a w3 loader which was disconnected.
Last year I used the 8N for some grading work and shut it down for the winter.

When I tried to start it this spring, it would not start. I pulled a plug and checked the spark and it look like it had spark. These are the things I've done since then:

1. The float was sticking on the carb, so I pulled it and tore it apart and cleaned it out and checked the settings.
   1. the 8n still did not start
2. I bought a new carb
   1. Still did not start
3. Pull the distributor (front mount, 6 volt)
   1. Put new points and condenser in and set the gap (.015) and the timing (straight edge.)
   2. Replaced the cap
   3. Replaced the coil The old one had a lower resistance than the one show in a YouTube video. The new was was the same as the video.
   4. Still did not start.
4. I put a multimeter on the coil post and measured the voltage,
   1. ...151.jpg shows the voltage with closed points,
   2. ...226.jpg shows the voltage with the points open.
5. I put my old coil back on and measured the voltage with closed points again
   1. …424 shows the voltage with my old coil with points closed.

This old farts brain is stumped, but I know one of you folks out there knows what is wrong.

Any HELP???

The high desert Septuagenarian

Never mind, I figured it out myself.

I dug out my wiring diagram and parts list and discovered the "ballast resistor".

1. Various websites all agreed that it's resistance should be "0.6" ohms.
2. After disconnecting the battery, I measured the resistance from the battery cable to the coil post with the key on.
   1. It was "1.6" ohms instead of 0.6 ohms.
3. Applying Ohms law, (I=E/R)
   1. the 1 ohm coil and the 1.6 ohm ballast resistor = 2.6 ohms
   2. 6.78 volts/2.6 ohms = 2.607 amps
   3. E=IR = 2.607 amps x 1.0 ohms (the coil) = 2.607 volts.
4. The meter reading on the coil was 2.63volts, so it all made sense. The ballast resistor was absorbing to much voltage resulting in the weak spark, since the voltage across the coil should have been 4.23 with a 0.6 ohm ballast.

I had a 0.8 10 watt resistor laying around the lab so I rigged up a direct connection between the battery and the coil through it, disconnected all the plug wires, and plugged a spark plug that I had stretched the gap to .118" (the book said the coil should be able to jump a gap of "3/16" or .187"). With the key on using the existing ballast, the coil could not jump this gap. With the bypass ballast, it could.

Problem solved. I hope I can tilt the engine cover up far enough to be able to replace the old ballast resistor.
BTW, I posted all this detail in the hopes that it may be of use to other members with the same type of problem.

The High Desert Septuagenarian

 

[JMOR]

Never mind, I figured it out myself.

I dug out my wiring diagram and parts list and discovered the "ballast resistor".

1. Various websites all agreed that it's resistance should be "0.6" ohms.
2. After disconnecting the battery, I measured the resistance from the battery cable to the coil post with the key on.
   1. It was "1.6" ohms instead of 0.6 ohms.
3. Applying Ohms law, (I=E/R)
   1. the 1 ohm coil and the 1.6 ohm ballast resistor = 2.6 ohms
   2. 6.78 volts/2.6 ohms = 2.607 amps
   3. E=IR = 2.607 amps x 1.0 ohms (the coil) = 2.607 volts.
4. The meter reading on the coil was 2.63volts, so it all made sense. The ballast resistor was absorbing to much voltage resulting in the weak spark, since the voltage across the coil should have been 4.23 with a 0.6 ohm ballast.

I had a 0.8 10 watt resistor laying around the lab so I rigged up a direct connection between the battery and the coil through it, disconnected all the plug wires, and plugged a spark plug that I had stretched the gap to .118" (the book said the coil should be able to jump a gap of "3/16" or .187"). With the key on using the existing ballast, the coil could not jump this gap. With the bypass ballast, it could.

Problem solved. I hope I can tilt the engine cover up far enough to be able to replace the old ballast resistor.
BTW, I posted all this detail in the hopes that it may be of use to other members with the same type of problem.

The High Desert Septuagenarian

You didn't say that it runs.....therefore, premature to say, "problem solved".

 

[HowardH]

You didn't say that it runs.....therefore, premature to say, "problem solved".

Oh ye of little faith!

 

[Btzj02]

Oh ye of little faith!

You will have to give us a final report when your running.

 

[HowardH]

You bet.
I didn't want to fire the engine without key control. The guy that sold it to me had disconnected the W3's pump and told me some gibberish about the hydraulic controls. I used to own a badass Pettibone B400 backhoe I had rebuilt, so I know a little about hydraulic controls.
So if there is a problem and the system is trying to move one of the cylinders, I want to be able to kill the motor before any damage is done.
I just put a new HYDRAULIC COUPLER HUB CENTER MEMBER on the pump and reconnected it, but the workings of the hydraulic system are an unknown. I drained what I could of the hydraulic oil, and it looked clean.
My new resistor s/b here wed-fri so I'll let you all know.

The High Desert Septuagenarian

 

[used red MN]

You didn't say that it runs.....therefore, premature to say, "problem solved".

Oh ye of little faith!

I didn't want to fire the engine without key control.

Hello Howard, welcome to YT! Maybe you have a wiring alligator clip in “your lab” that can easily be disconnected as a switch or simply strip an inch or so off two ends of stranded wire that simply can be pulled apart. The reason I say this is that the fact that you have voltage at your coil most likely means the resistor is still functional for your tractor. The resistor is just a coiled wire and usually when they fail a section of the wire burns out and they no longer conduct power. (see link) Example resistor I suppose you could have the exception. I just would hate to see you go through the struggle of replacing it only to still be at step one, tractor won’t run. You really don’t need to place that resistor in the power feed to the coil for a short term trial, just a full voltage jumper from the battery negative post will work, assuming the tractor is still the original positive ground.

 

[Mad Farmer]

Plugs clean/dry/good?

Run a jumper wire from the Bat terminal on the terminal block to the coil wire side of the resistor (bypass key and resistor).

Will it start/does it have spark? Full batt voltage to the coil won't hurt it for a short time, or the points unless they are closed.

Disconnect the jumper as soon as you test for spark, and/or try starting.

Carb does have gas flow?........

 

[Non-farmer]

The guys at Pertronix told me to remove ALL resistors from the circuit when I put EI in. From day 1 of my 12 volt conversion, I've had no proverbial white ceramic blob, with no ill effects to the coil. Pertronix insisted I also bypass the OEM ballast resistor too. Coil still happy, that's been 3 or 4 years. These square coils are tougher than people give them credit for. Certainly, testing something with the resistors bypassed will not vaporize the coil in a millisecond

 

[HowardH]

You bet.
I didn't want to fire the engine without key control. The guy that sold it to me had disconnected the W3's pump and told me some gibberish about the hydraulic controls. I used to own a badass Pettibone B400 backhoe I had rebuilt, so I know a little about hydraulic controls.
So if there is a problem and the system is trying to move one of the cylinders, I want to be able to kill the motor before any damage is done.
I just put a new HYDRAULIC COUPLER HUB CENTER MEMBER on the pump and reconnected it, but the workings of the hydraulic system are an unknown. I drained what I could of the hydraulic oil, and it looked clean.
My new resistor s/b here wed-fri so I'll let you all know.

The High Desert Septuagenarian

Ok, here's the skinny, and I could use some suggestions for other items.

1. I got the ballast resistor and tried to change it out but after getting all the wires off, the screws holding it to the frame were seized, and I could not get it off.
2. Just for drill, I checked the resistance of the old ballast and son-of a b**ch it was 0.6 ohms. (you were right JMOR).
3. I handled the wires going to the ignition switch and they came apart in my hands. Someone had replaced the ignition switch and used crimp connectors (UGH). The first three pictures show the mess.
4. If any of you young guys take advice from old farts NEVER USE CRIMP CONNECTORS FOR OUTDOOR WIRES EXCEPT IN AN EMERGENCY!!
5. Use flux, solder and shrink sleeving. (4th picture.)
6. Anyway, I rebuilt the harness and she fired right up.

So on the new problem. I had mentioned that I had reconnected the W3 hydraulic pump back up that the previous owner had disconnected. When I fired the motor, the RPMs were pretty low. When I pushed one of the W3 levers forward from neutral , the RPMs shot up, so the controls have a problem. The return hose was hot, and the valve body burned my hand. So I removed the hub connecting the pump.

I had always planned on replacing the two controls with a joystick. I'm sure some of you folks have done that. So I'm looking for recommendations. The Surplus Center has some for a couple of hundred and change like this one:

2 Spool 10 GPM Joystick Loader Control Valve w/Float Chief 220957 | Chief | Brands | www.surpluscenter.com

2 Spool 10 GPM Joystick Loader Control Valve w/Float Chief 220957, Chief, 2 SPOOL JOYSTICK LOADER CONTROL VALVE WITH FLOAT Brand new, CHIEFChief,220957,

www.surpluscenter.com

Any suggestions?

The High Desert Septuagenarian

 

[Mad Farmer]

Yes solder wires in, then I paint with liquid electrical tape before the shrink tubing and after at the tubing ends.

Anybody know a good source of solder on connectors (round spade etc...)?

 

[OldBlue61]

I don't have an issue w/ crimp-on connectors, provided they are the right kind. I use a marine-grade set from my boating days. After crimping, you apply heat (just like shrink tubing) and the insulator shrinks around the connector and has a silicone-based adhesive that seals the connection.

 

[Non-farmer]

I've used standard rosin core solder and standard crimp connectors with good results. Cover with shrink tube and I've not had a failure. If I had to go out and buy more, I'd go with marine grade, but I've had no issues using what I have in inventory.

Imo, the electrical system on an N is an absolute joy to work on due to its overwhelming simplicity. It doesn't get any easier than this.

Edit: don't underestimate the value of good crimpers. I swear by T&Bs. (I think that stands for Thomas and Betts.)

 

[HowardH]

I don't have an issue w/ crimp-on connectors, provided they are the right kind. I use a marine-grade set from my boating days. After crimping, you apply heat (just like shrink tubing) and the insulator shrinks around the connector and has a silicone-based adhesive that seals the connection.

Your right. I meant to say "don't just crimp crimp connectors, solder them". The wire I made in the picture uses crimp connectors, but the connector and the wire are tinned then soldered and shrink-wrapped.