ign key and resistor ?s

Mad Farmer

Well-known Member
Location
Northeast
Hi folks.

1940 9n original 6V + ground system. Has always started well and runs great when weather is cold. Recently started dying when worked hard brush hogging in hot weather, takes ~ 1/2 hour then cuts out. I get it back home by running a jumper from coil side of resistor to hot terminal on resistor assy.

I've read about the issue with ign keys here.......

I checked all wiring for continuity and voltage when cold overnight and all was fine except one strange thing: both sides of resistor showed a bit of voltage, WITH THE KEY OFF? I checked it again with coil disconnected, thinking maybe coil charge was leaking backwards, still the same. When cold it has battery voltage (6.3V) on both sides of resistor and to the coil. The strange voltage at the resistor w/key off does not drain battery down, it can sit two months and start up.

So yesterday took the multi-meter into the field with me when cutting. When it died I checked voltage at both sides of resistor: key side 4.9V, coil side 2.6 V. Key AND resistor bad? Even after sitting an hour still would not start without jumper wire. Won't start with jumper on key side of the resistor either.

So I ordered a new resistor assy and ign key today. But have a couple of questions???

1) do these resistors work by heating up when current is flowing. That is so you get full voltage when starting but a voltage drop after a bit of running. What is normal voltage drop?

2)Any ideas on the voltage (0.3V) at resistor w/key off? My meter is O.K.

3) How much of a PITA is it to get the mounting screws out of the resistor plate? I'm hoping not to have to remove the hood, just battery. Plan is to hit them with PB Blaster then give them a few wacks with a hand held hammer Snap-On impact driver, if I can get a swing with the hammer........

Thanks for any advice in advance.
 
" 1) do these resistors work by heating up when current is flowing. That is so you get full voltage when starting but a voltage drop after a bit of running. "

Yes.

" What is normal voltage drop?"

The oem ballast resistor is .3 ohms cold and 1.7 ohms hot. Voltage drop would depend on current draw.

" 2)Any ideas on the voltage (0.3V) at resistor w/key off?"

Defective ignition switch



" 3) How much of a PITA is it to get the mounting screws out of the resistor plate?"

Depends on the last time it was removed.
75 Tips
 
Mad Farmer, you are on the right track. I like the P.B. Blaster idea. Then if the screws don't want to co-operate, try rapping on the end of the screwdriver first. Then if that doesn't work try your impact driver. Let us know how it worked out.
 

the mounting screws for the resistor were pretty crusty on mine, and i needed to replace it. but with a big straight blade screwdriver and a dose or three of PB blaster, they came out without too much protest.
 
"When cold it has battery voltage (6.3V) on both sides of resistor"

This is normal with the points open or coil disconnected and the
key on. No current flow, no voltage drop. Battery may be low.

As for the screws, they can be stuck pretty good but if you're
replacing it anyway, you can chip the old resistor off and grab
them with a pair of ViceGrips. Just don't break them off.
 
Don't assume anything, nor start buying new parts and replacing until a true root cause problem solving procedure is performed. Your dying out issue could be fuel related, not electrical. Do you have enough gas in tank and valve open 2 turns? When it stops, check for fuel flow at the carb. Just to clarify how the N fuel system works, the tank capacity is 9 gallons with a 1 gallon reserve. The Fuel Sediment Bulb Assembly functions by accessing the Main intake by opening the valve stem 2 Full Turns. When fuel gets low, opening valve ALL the way accesses the 1-gallon reserve. Fuel flow can be checked by removing the drain NPT plug at the bottom of carb, opening valve 2 turns and seeing if you get 1 pint in 2 minutes. Sediment Bulb has two screens and the carb has one in the brass elbow inlet. There also is a vent hole on the top of the gas tank. This is only about a 1/16? in diameter and gets plugged over time. It is a time consuming job to unplug and thus many have never been cleaned. The tank must be drained first, then the dash, carb, grille, doglegs, are removed so the hood with gas tank attached can be removed. It takes 2 minutes to clear the vent, 2 hours or more to remove everything related, 2 hours to reinstall. Next, just because you say your system is 6V/POS GRN does not mean it is wired correctly otherwise. I'm not saying it is or isn't, just verify first. Google WIRING PICTOGRAMS by JMOR" for all the correct ways to wire these N's. Do you have the essential manuals? They will have wiring diagrams and part listings as well. The 1940 Ford-Ferguson 9N Tractor, as with all FORD vehicles of the era, used the 6V/POS GRN electrical system. In early 1940, on or about s/n 12500, the original small 9N-10000-A 2-Wire/2-Brush 'B' Circuit generator that used the square voltage regulator was replaced with the 9N-10000-B generator, a 1-Wire/3-Brush 'A' Circuit type and now used the round-can cutout circuit. It was also a small unit, and had the 3rd Brush slider HI-LO button on the back panel. Both of these had current output rating of 7 AMPS. In August, 1940, the 9N-B genny was replaced by the new 9N-10000-C generator -an 11.5 output, 1-Wire/3-Brush, 'A' circuit unit. The 3rd Brush was now adjusted by a rotating screw from LO to HI. ALL N's used the Ballast Resistor. The cutout was used up til the end of 2N production by January,1947. The 9N/2N starter used a 1-Wire unit and NO solenoid installed. Here is a LINK to get the correct new key switch. They also stock the correct Ballast Resistor -there are differences depending on model year-s/n.

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FORD N-SERIES TRACTOR FUEL TANK & VENT:
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Tim Daley(MI)
9N IGNITION SWITCH
 
Hi Tim thanks for the info but yes I'm sure it's electrical.

I've had this tractor over 30 years now. It came with a 3-brush model A generator, crusty wiring, blown amp meter, and no lights. I had the model A genny rebuilt, twice, before I found a nice single wire 3-brush 9N genny (the model A gennys work fine when they work). I redid all the wires myself, did not buy any pre-made, used highest quality wire from an electrical supply store, overkill on gauge thickness and quality insulation. Where possible I used soldered connections. When I fixed the lights, and it "stopped charging", I learned about the 3rd adjustable brush. There never was an issue with the ign switch or the resistor before, so I left well enough alone there. It idles fine, has good power, and starts all winter when I plow the snow. Even though it lives outside under a military tarp.

Only recently did it start losing spark when ran hard in hot weather. It did almost seem like I ran out of fuel (done that before), but I checked that. If I didn't have the alligator clip jumper wire I'd of had to leave it overnight in the field to cool down. I was tempted to look inside the distributor, before I checked things with the multimeter when it died in the field last time. I should probably add a cheap test light to the tool kit, for crude voltage test, as I don't usually carry the multimeter with me. Lamp brightness will give you a ballpark idea of voltage.

I do carry another much thicker/shorter jumper wire for when/if the genny cutout fries out. That one is tied to the cutout with a thin rope in case I need it. I've used that jumper in place of a shot cutout for weeks. I just need to remember to hook it up after starting, and pull it off before I shut things down.

Fuel system/out of gas? I've replaced sediment bowl/petcock assy, fabricated a new metal fuel line (double flared), and rebuilt the OEM carburator. I know about all the filters and if I'm ever not sure about fuel I give the carb a rap first off to see if the float might be stuck, then check the drain plug on the carb for fuel.

Other work I've done is new rubber all around, steering shaft/sectors, starter motor, manifold/adjust valves, tune ups (sparkys/points), and soldered up a couple of leaks in the radiator. It's not pretty but usually runs well. I have the original plow and spring harrow, a 5ft rotary cutter, grader blade, snow plow, and rear scoop bucket. If you know your limitations it will also skid logs pretty well; I have a small sawmill

I have been fortunate enough not to need to go inside the engine/transmission/rear end/or hydraulics..........yet.

I brought the IT manual when I got the tractor, and also have the Ford service and parts manuals.

I taught myself how to rebuild engines from scratch/totally stripped: 500hp SBC, motorcycles, chainsaws. I don't like the new cars where you need a computer to work on them, but am pretty good with fuel injection systems on older stuff.

I try to educate myself as much as possible before I go to fix stuff, but am not above asking for advice or suggestions. Hence this thread. Thanks to all for your help!
 
See my last post:

"Fuel system/out of gas? I've replaced sediment bowl/petcock assy, fabricated a new metal fuel line (double flared), and rebuilt the OEM carburator. I know about all the filters and if I'm ever not sure about fuel I give the carb a rap first off to see if the float might be stuck, then check the drain plug on the carb for fuel."

Key and resistor assy came in today. Will let everyone know how much fun it was taking out the resistor block mounting screws..........
 
A follow up on this.

I got the parts quick as manure from this site, thanks!!! Took a while to get around to installing due to weather(have to do outside) and other must doos.

I have an oversize battery( 780CCA) with a marine bat box I got from Carquest. The old 9N came without a bat box, the smaller bat would pizz when charging and it was not good for the metal. I had to cut down the bat box to make it fit but works great It's a PITA to shoehorn in/out, but they last 8-9 years here in the cold northeast and I plow snow with the 9N. I can get PN #s if interested.

I got that bat out and first cleaned the screen on the airfilter, lubed the points on throttle assy and cleaned out the area. Can't do that with bat installed...

To my surprise, the two mounting screws on the resistor block came right out. Some good soul has either greased or never-seized them. No need for impact driver.

The wires had all been done by me years prior and in good shape. The lights had stopped working so I got out the multi-meter and found the switch was bad. I had wired a fuse into the switch when I did the lights but it was fine. Crap! Don't have time to go to parts store, but had a old Jacobsen LT I keep for spare parts for my Ford LGT. It had a toggle light switch, the multi-meter said it was O.K. so that went in first. Lights fixed.

If found the YT ignition assy was a little smaller dia than OEM, and that the nut that holds it inside the hood MUCH thinner. That made it a PITA to tighten it, it's recessed where it mounts inside the hood. The threads dia were smaller so could not use the nut from the old switch. If I knew in advance would have fabricated a spacer from a large washer. I used a cold chisel to tap the nut tight as could not use a wrench nor any sort of pliers.

Other notes from new vs old. The old key switch had spade connectors for each wire. Not sure on the new one as they used some kind of shrink-wrap on the connectors rather than grommets. I saved the old switch/wires and all other parts. I put the new switch in, checked it with meter so the position of on/off key would be the same. NOTE: the YT wire/switch MIGHT have had spade connectors , BUT, the shrink wrap made it hard to tell. The multi-meter said all was fine, so I left well enough alone. I like the spade connectors on the old switch.....

A little bit of PITA putting in new resistor block. OEM mounting screws were better quality and 1/4" longer, I reused them. Hard time getting them started straight, had to take a round file and open up the holes in the resistor block just a bit, then fit fine. The screws went in with fresh never-seize.

Then some more fun began! The OEM resistor block had 5/32 posts, the new one 3/16. The new key switch came with wire terminals for 5/32 posts, they would not fit over the posts. The terminals are REALLY small so had to be VERY careful using a 3/16 portable drill to ream them out. Got those fitted. When I rewired, the small connectors for the lights and dist to resistor block were 3/16 already so no problem there. The ones on the large gauge wires to the amp meter and genny much bigger.

Went to reconnect the wires. WTF??? the 11/32 wrench doesn't fit all the flats on the terminal post nuts. CHEAP NUTS!!! If you purchase one of these, go to hardware store in advance and get some quality nuts/washers, save yourself agrivation. I did not have time so took out a flat file and fitted each nut to my 11/32 open end (not a cheapie, old USA craftsman), file 3 of 6 sides. Maybe china part and 9mm? 11/32" = 8.73 mm. Anyway, fix the nuts so you are not cursing with your face looking into the battery box....

Got things hooked up, made sure all wires were routed O.K., used a couple of zip-ties. Took out multi-meter again and put a jumper on hot terminal of resistor block then tested/continuity from there to: 1) light side of light switch, on and off, O.K. 2) Key side of resistor, key on and off O.K. 3) coil side of resistor, key on and off O.K. Success !!!

I ------ and moaned a bit shoe-horning the battery back in. But it started right up, amp meter showed a charge, and the lights worked.

I ran the tractor a few hours brush hogging (5ft House). Was running good on a field not mowed yet, 2nd gear in hood high golden rod without a bog. When it got good and hot it again missed a bit under REAL heavy loads, but did not stall or fail to re-start. Called it a day. Yes it has plenty of fuel..........

I think I need to now check the dist. It's a very long time since points were done. But has been running and starting fine except when very hot. I tend not to fix things that are not broken..... Points might have worn down with the rubbing block so timing is O.K. but dwell is off. That or coil. I have a NOS OEM ford-new holland tune up kit (1991?) , and a couple of sets of echlin points (NOS USA). That will be the next project.

Make some notes of the YT parts to save any hassles if you do an install: The nut on the key switch, the size of the posts on old/new resistor blocks, the size of the wire terminals on YT key switch wires, and the crappy nuts for the resistor block terminals Overall I'm happy with quality, and more than happy with service/shipping.

Thanks to all for your help and suggestions!!!
 
Thanks for the follow up. Many times we never hear back.
Glad to hear you got it going again!
I always use a nut driver on those nuts.
Never noticed that they might be a different width across the flats.
I'll have to check that out when I do the next one.
I have bought brass drain plugs for the carbs made that way.
 
(quoted from post at 14:29:24 08/11/18) Thanks for the follow up. Many times we never hear back.
Glad to hear you got it going again!
I always use a nut driver on those nuts.
Never noticed that they might be a different width across the flats.
I'll have to check that out when I do the next one.
I have bought brass drain plugs for the carbs made that way.

Real sure about all of the above.

I've wrenched all sorts of things. Way back it was, bicycles, USA made lawn mower engines on mini-bikes, then Jap dirt bikes, then free cars, then newer free cars/trucks, then hot-rod cars ( >500 hp SBC from bare block 69 Lt-1), then fuel injection (GFs volks van), all sorts of early tractors, early LGTs, Wisconsons, chainsaws ( mostly stihls/homies free rebuilt from scratch), newer car fuel injection < ~ year 2000......

I gave up on the newest cars. Can't work on them so I won't own one. Some where in there I went to school too.....
 
(quoted from post at 19:22:23 08/11/18)
(quoted from post at 14:29:24 08/11/18) Thanks for the follow up. Many times we never hear back.
Glad to hear you got it going again!
I always use a nut driver on those nuts.
Never noticed that they might be a different width across the flats.
I'll have to check that out when I do the next one.
I have bought brass drain plugs for the carbs made that way.

Real sure about all of the above.

I've wrenched all sorts of things. Way back it was, bicycles, USA made lawn mower engines on mini-bikes, then Jap dirt bikes, then free cars, then newer free cars/trucks, then hot-rod cars ( >500 hp SBC from bare block 69 Lt-1), then fuel injection (GFs volks van), all sorts of early tractors, early LGTs, Wisconsons, chainsaws ( mostly stihls/homies free rebuilt from scratch), newer car fuel injection < ~ year 2000......

I gave up on the newest cars. Can't work on them so I won't own one. Some where in there I went to school too.....
Not implying that your observations are not correct. I just hadn't noticed.
I stopped using open end wrenches a long time ago except where they are absolutely required.
They cause too much damage to things like fuel and brake lines.
 

No 11/32" nut drivers nor sockets, those are rare birds, you got them?

Didn't try a 9mm but had that, in retrospect that might have worked. In my mind I have what usually works: 13mm ~1/2", 14mm ~ 9/16", etc.............

Did have quality ignition wrenches so that was the ticket, but the nuts made me nuts.......

Have a great weekend
 

Maybe I'm reading this wrong?

I have an I'll fitting 11/32 nut. Not a fuel/brake line fitting.

I have a full set of std and metric brake line wrenches. They are basically deep well 6-point box end wrenches, with a slot cut to get by the line. Never ever seen one in 11/32 and it would be worse than an open end for the job at hand. So I do have std. and metric brake/tubing wrenches, double flare tools, and rolls of brake line. I make all my own lines and buy the ends/couplers.

Nut driver or socket in 11/32" , yes but those are not common either. Might have an 11/32" socket but not in my go to box.

I do have full sets of ignition wrenches in std and metric. Maybe I should have tried a 9mm?

I don't want any metric on this old Ford. I worked on a friends P/U truck last fall putting a transmission in (92 GMC). What a clusternnalert! Metric mixed with standard, and uncommon metrics prevalent. E.g. 15mm.

I'll keep my pre-80s cars/trucks.

external_link can keep the change......
 
"No 11/32" nut drivers nor sockets, those are rare birds, you got them?"

Yes, I have them both. Rare birds in a set you can buy today maybe, but
not really all that rare. I have a lot of old tools, but you can find them
readily at yard sales or auction sales. Obviously the green one is
not old. I just had to clean some sea salt off of it to read it.
Normally, I don't bother to dig for a size, I just grab the one that fits
and that may be a metric one.
A 1/4 drive socket on a drive handle works fine too. SAE or metric.

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