Another Front Mount Distributor Question

[Non-farmer]

Yep, Jim.

 

[RWS904]

I was wondering if that was the case. Double check your firing order since you have replace the plug wires. My manual is out in the garage, but I'm pretty sure it's 1,2,4,3 CCW.

Good advice, I double checked last night and verified the wires are routed correctly.

 

[will-max dairy]

I still haven't seen if you've tested spark.

Even with a new coil, and a "repaired" or "tuned" distributor...there are many ways for spark to be weak. For instance, on these front mount units, there are a couple of springs (one coil and one flat) that connect the coil to the distributor body... these can be bent the wrong way, or making weak connection...

I've even seen one post here that chased down one problem after another, only to realize that the distributor wasn't even spinning (I don't think this is your problem...) but... you need to simply test spark at the end of the plug wire...each of them, in this case. It is the ultimate sanity check that the entire system from generator, to keyswitch, to ammeter, to ballast/in-line resistor, to coil, to distributor, to plug wire, to plug... is working.

Testing individual components is worthwhile, but no substitute.

 

[RWS904]

Hi Will-Max, I haven’t tested for spark at individual wires recently. I did order the variable spark tester you posted and should have it by Friday.

 

[will-max dairy]

Hi Will-Max, I haven’t tested for spark at individual wires recently. I did order the variable spark tester you posted and should have it by Friday.

Even if it doesn't solve this particular problem, it's 11 bucks that should save you some time/hassle over the life of your tractor.

 

[RWS904]

In the meantime I have determined the ignition switch is definitely a problem. Resistance between the two leads (measured out of circuit) with the key on varies from anywhere from 6 ohms to 180 ohms depending on position of the (corroded) wires at the terminal lugs.

Edit - not “plug terminals”, should have been “terminal lugs” on the ignition switch wires.

 

[Mad Farmer]

In the meantime I have determined the ignition switch is definitely a problem. Resistance between the two leads (measured out of circuit) with the key on varies from anywhere from 6 ohms to 180 ohms depending on position of the (corroded) wires at the terminal lugs.

Edit - not “plug terminals”, should have been “terminal lugs” on the ignition switch wires.

I touched on checking the key switch post #6, <----------- That or a bad resistor, both you can patch up to run with a jumper wire.

 

[RWS904]

Yes Sir, you were the one that inspired me to try both last week. I was using a cheap Harbor Freight test lead with alligator clips on small gauge (maybe 20ga) wire. I should have used something heavier and cleaned up contact areas first. At any rate, good advice, thanks!

 

[Mad Farmer]

Yes Sir, you were the one that inspired me to try both last week. I was using a cheap Harbor Freight test lead with alligator clips on small gauge (maybe 20ga) wire. I should have used something heavier and cleaned up contact areas first. At any rate, good advice, thanks!

Glad you found the problem

I keep a few jumper wires in the Ns toolbox. Thinner one for low amps like jumping the key, ign resistor, or light switches and thicker for more current. Also keep a short thick one to jumper the voltage cutout for the 3-brush generator.

 

[will-max dairy]

Yes Sir, you were the one that inspired me to try both last week. I was using a cheap Harbor Freight test lead with alligator clips on small gauge (maybe 20ga) wire. I should have used something heavier and cleaned up contact areas first. At any rate, good advice, thanks!

Between the 2N and the 641, we have been through three or four key switch assemblies in the last ten years.

They last about as long as a goldenrod gall fly...

 

[Non-farmer]

Between the 2N and the 641, we have been through three or four key switch assemblies in the last ten years.

They last about as long as a goldenrod gall fly...

My 2N died a couple of minutes into mowing the lawn yesterday. Before I walked the 150 yards to get stuff to test with, the last thing I did before I got it to restart was wiggle the key. Switch now prime suspect, maybe 5 years old.

 

[will-max dairy]

My 2N died a couple of minutes into mowing the lawn yesterday. Before I walked the 150 yards to get stuff to test with, the last thing I did before I got it to restart was wiggle the key. Switch now prime suspect, maybe 5 years old.

They may be getting an "inductive kickback" from the coil when opening the ignition circuit, when you turn the tractor off.

If it was in a piece of electronics I was designing... I would be considering putting a TVS across it.

Or... maybe it's just because they are a mechanical switching component (not solid state)... and cheap...

 

[RWS904]

Good morning all. I received the spark tester that Will-Max recommended and tried it out this morning.

I tried it on all four plug wires, starting at #4 and working forward with a fully charged battery at the beginning. I would describe the spark as strong and loud at the beginning, but intermittent at best.

Fuel off, just cranking to check for spark, the firing was erratic, not rhythmic as I would have expected. By the time I got to #1 wire, the battery was getting weak and the spark was too. Erratic spark on all wires.

As a re-cap of what has been replaced:

New points (.015”), condenser, cap, and rotor.

Coil is ~2 months old.

Alternator (old one’s output was ~1V, new ~14V)

Ammeter (old one was inoperative, new one works)

Ignition switch (old one showed high resistance with key on)

Had the following items new in the (forgotten) box from the previous owner and installed them as well:

Plugs and wires.

Terminal block/resistor. (Old one had resistor bypassed and routed to a rusty ballast resistor, zip tied to a wiring loom).

As an added bonus because I like wiring projects, replaced the following wires after discovering nicks in the coil wire insulation:

Coil wire, alternator wire, ammeter jumper wire, battery side ammeter wire. Aviation grade wire and terminal lugs installed.

 

[Non-farmer]

Fuel off, just cranking to check for spark, the firing was erratic, not rhythmic as I would have expected. By the time I got to #1 wire, the battery was getting weak and the spark was too. Erratic spark on all wires.

How long were you turning the engine over for each cylinder? I can't imagine a properly working battery getting weak just testing spark.

 

[RWS904]

How long were you turning the engine over for each cylinder? I can't imagine a properly working battery getting weak just testing spark.

Probably 30- 40 seconds each. Battery was load tested last weekend and deemed “good”. Maybe not so much…

 

[Non-farmer]

Ok, that's much longer than I turn mine over to check spark. Maybe the battery is not an issue. I usually only do about 5 seconds, maybe 10 at the most for a cylinder.

 

[will-max dairy]

Ok, that's much longer than I turn mine over to check spark. Maybe the battery is not an issue. I usually only do about 5 seconds, maybe 10 at the most for a cylinder.

Yeah...if you are by yourself, it helps to test in the dark.

 

[Non-farmer]

I don't have a helper. I think I've always done it in the daytime, often out in the sun.

 

[RWS904]

I don’t have a helper either, but I recorded a few seconds early this morning with the two testers connected to cylinders 2 & 3.

I will doublecheck the gaps on the testers when I get home to make sure they were set to the same distance.

 

[RWS904]

Overdue for an update here since I last posted a couple weeks ago. Thanks to ”Wore Out” I found an Allen E-1403 condenser and coil tester and it worked right out of the box. A member of another forum sent me a pdf version of the operating instructions and I was up and running in no time.

Long story short, I had a number of issues working against me, one was definitely self-induced. At some point when installing the distributor cap, I ended up bending the spring on the rotor so it wasn’t making consistent contact with the cap’s center electrode.

I tried six different “new” condensers at various times. In the end, I discovered the original (OLD when I got the tractor) condenser had a nick in the wire and exposed conductor. I shortened the wire and crimped a terminal lug on it and reinstalled the condenser with a new rotor and CAREFULLY installed the cap. Installed a new coil from AMZ (the river company) and it’s been running great for a couple weeks straight.

Just for grins, here are two short videos of testing a weak 6V coil and a normal 12V coil on the Allen tester. I am now a firm believer in spark gap testers (thanks Will-Max).