TVZ

Member
My 9N seems to be running a little slow. A mechanic friend said he thought it sounded like it might be missing. He suggested that I alternately push the spark plug wires off while it was running to see if there was one that did not make a difference. I did that, and the one at the front did not seem to cause it to slow down. However, I checked for spark and it looked ok to me. Does this mean I have bigger problems in the cylinder? Or might the spark look ok but not really be good?

I ordered some new plugs to try, but although I ordered Autolite 437, I got Autolite 3922 with a sticker that said Autolite 437. Are they the same, or is the sticker mistaken?

Thanks
 
TvZ,The 437 is the correct plug and heat range C8 and thread reach 0.4375 Inch,The Autolite 3922 plug has a lot longer reach Thread Reach (In): 0.750 Inch ad a heat range D11.The 3922s are way to long and could even contact and bend a valve.

DON"T USE 3922 Plugs!
 
DO NOT "push the sparkplug wires off" to check for a miss.

The spark has to go somewhere and with the wire off of the sparkplug it will try to start s "carbon track" on the distributor cap or rotor as it seeks ground!

GROUNDING the wires at the sparkplug one at a time accomplishes the same thing WITHOUT the risk of cap or rotor damage.
 
Thank you for the tip, Bob. This may be a dumb question, but how do I ground the wires? Seems like the caps would prevent that or make it very hard...
 
If they have rubber boots they can be pushed back, exposing the terminal. Some silicone spray makes that easier. I have even snapped sparkplug connectors down over a piece of fine wire, leaving a bit exposed to short to, and (of course) remove the fine wire when I'm done.
 
I would check this way..... Start-up the tractor. Turn off any shop lights and see if there might be some little sparks along the path of the plug wires. This would cause the engine to MISS.

Might need to replace the plug wires with solid core wire. TSC stores carry kits for N's.

I had to replace the plug wires on my 9N because of the same MISS problem.

GEE that was already over 10 yrs. ago.

HTH John,PA
 
hooking a timing light to each plug in turn and just watching the light while it's running helps find which cylinder is miss-firing quickly.
especially handy to find misses that are random. Like watching a very fast heartbeat. You'll see a problem with the 'rhythm' immediately.
 
I would caution using TSC copper spark plug wires. Last week I installed some on a 2N. What a struggle. The insulation is so stiff that the wires have their own memory and are difficult to route. I used the original tube for the plug wires, distributor wire and generator wire.
 
The AutoLite 437 plug should have that number etched onto the white ceramic body, if anything else take it back. Another very good alternative is the Champion H-12 plug. I use both and have had great life and success with both. The CHAMPION H-12 will also be listed as the 512 number. The original Ford Tractor 14mm plugs are listed as Champion H-10 in all the Operator's Manuals Specs. They didn't have the H-12 nor Auto Lite version yet. H-10 will still work too but the H-12 is a hotter plug like the 437's...

Tim *PloughNman* Daley(MI)
 

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