Fuel but No fire. Theory?

Okay, i finally got my '47 front mount 12v to crank. Had to re-wire half the dang thing. Replaced sediment bowl gasket and screen (was missing screen) cleaned carb, replaced gaskets (was leaking heavily) wont start, wasn't expecting it to. Was sitting for years under shade. with ignition on.
So im going to order points, condenser, plugs, maybe new wires and a coil.
I have a theory though, anyone who is electrically inclined please answer. Can i run a continuity check from the resistor to the plug wires to check if everything is good? or would the points opening and closing automatically void that test?
What should my coil be reading at the top post on it? its saying between 3-5V when cranking.
 
Also, what kind of coil should I buy? I see a $14 coil in the store here, but also a $38 coil. The one i have on it now is a square one. Not sure if it is a 6v or 12v though.
 



The first thing you need to check is for battery voltage at the coil. Yes, you need a meter for that, not a light. With the key on, you should see battery voltage battery with the points open and about half that with the points closed. If you do not see either, the problem is between the battery and the coil, e.g., the resistor, ignition switch or a bad connection.

Assuming that the bushings & advance weights are ok (*see below), & that you have correct voltage to the coil , the most common reasons for no spark or a weak spark on the front distributor are below. Check each one carefully. Even if you find a problem, check all 10:

1. The insulator under the brass concave head screw & where the copper strip attaches. (it's fiber & will wear out; poke & prod w/ your meter leads to make sure it still works) If you need to replace the insulator, use a
.250 x 3/8 nylon square nylon anchor nut available at most big box home stores.

2. The pigtail at the bottom of the coil not making contact w/ the concave head brass screw inside the distributor. (With the coil on, the pigtail must firmly contact the brass screw. No contact = no spark) Check for continuity between the top of the coil and the pig tail; a 6 volt coil will be around 1 ohm & a 12 volt coil should be 2 to 3 ohms.

3. The copper strip is broken or grounded to the plate. (look very carefully for cracks & breaks) .

4. The distributor is not grounded to the block because of paint or grease acting as an insulator. Or the points plate is covered in oil.

5. The tab on the bottom of the coil not making contact w/ the brass button on the cap. (With the cap on, the tab must firmly contact the brass button. No contact = no spark.) Check for continuity between the top of the coil and the tab; you should see about 6k ohms.

6. A grounding issue inside the distributor: Incorrect positioning of the spring clip on the plate causing the pigtail to ground. (the open part of the clip goes between 7 & 9 o'clock on the plate. That puts the straight part of the clip opposite of the timing screw at 3 o'clock) or the condenser wire is grounding to the plate or side of the distributor.

7. Incorrect seating of the coil on the distributor due to a loose bail or no gasket.(the coil must not move at all; if it does, replace the gasket or bail. Or stick some cardboard under the bail).

8. Water/moisture inside the cap due to gasket failure or the absence of a gasket. (the cap AND coil have gaskets)

9. Dirty/corroded/burned/incorrectly gapped or misaligned points. I use only Wells, Blue Streak or Echlin brand points (* *see below). If you are using quality points and cannot get the gap to open to .015, chances are you need to replace the bushings. If the shaft has any sideways movement AT ALL, the bushings must be replaced. (*** see below) If the tractor has been sitting unused for a few months, it?s highly likely that the points are glazed. Dress them with brown paper or card stock. Do NOT use a file or sandpaper. That removes the thin metallic coating on the surface and reduces point life considerably. With the points closed, you should have continuity between them; high resistance means they are glazed.

10. Burned rotor, cracked/carbon tracked cap. Brass ?dust? in the cap is a sure sign of bushing wear.

After find the problem & re-check the point gap, do a continuity check before you put the distributor back on the tractor. Before you start, make sure your meter/light works.

With the distributor still off the tractor, follow these steps:

1. Coil off, cap off, points open. One probe on the brass screw & the other on both sides of the open points. On the side closest to the cam, you should have continuity. Not on the other side! If you do, you will also have continuity everywhere because the points are grounded.

2. Coil off, cap off, points open. One probe on the brass screw & the other anywhere on the body of the distributor. You should have no continuity! Now, rotate the tang on the distributor....as the points open & close, you have continuity (closed) and lose it when they open.

3. Put the coil on the distributor, cap off, points open. One probe on the lead on the top of the coil, the other on the cam side of the open points. You should have continuity!

4. Coil on, cap off, points open. One probe on the lead on the top of the coil, the other anywhere on the body of the distributor. You should have no continuity!

At this point, I just put the distributor, coil & cap all back on the tractor as a unit. The reason I do this is because it is real easy to get the cap or coil misaligned trying to put it back together, one piece at a time. The result is something gets broken or you get a 'no spark' problem.

It's possible to put it back on wrong & break it. Look at the slot on the end of the cam shaft. Whatever angle it happens to be, turn the distributor tang to match it. Make sure you can tell the wide side from the narrow side on both the cam & distributor! (close counts). Place the distributor on the front of the engine, gently push it in place & slowly turn the distributor body until you feel the tang slip into the slot. Rotate the distributor body until the bolt holes line up. Hand tighten the two bolts until the distributor body is flush with the timing gear cover.

* Unscrew the plate hold down screw & remove the C clip to get the plate out. Remove the shaft & weights. The weights should freely move. The tracks should not be wallowed out.

** NAPA part numbers:

. Points: FD-6769X or ECH CS35

. Condenser: FD-71 or ECH FA200

. Rotor: FD-104 or ECH FA 300

. Cap: FD-126 or ECH FA 350

** Yesterday's Tractor kit:

Premium Blue Streak points (A0NN12107ABS), rotor, condenser, and gauge Part
No: APN12000ABSR

** nnalert's kit:

Heavy-Duty Point Set, Condenser, Heavy-Duty Rotor, Heat Range Matched Spark Plugs. Packed 6 to Master Carton. Contains: 1-9N12107 Point Set, 1-AONN12300A Condenser, 1-9N12200 Rotor,1-9N12104 Gasket Kit,4-AL437 Spark
Plug,1-015 Gauge, 1-025 Gauge.

** Distributor cam lube, Mac's Auto Parts:

http://www.macsautoparts.com/.../distributor-cam-lube...
one-7-8-ounce-381629.html?utm_source=google&utm_medium=paid_search&utm_campa
ign=paid_search_google_pla&scid=scplp58-20966-1&sc_intid=58-20966-1&gclid=CN
7P-sjQ9tICFYePswodaH0HRg

** Distributor cam lube NAPA:

https://www.napaonline.com/en/p/ECHML1

*** There are three ways to replace the bushings in a front distributor:

1. Buy new bushings (part numbers 9N12120 front & 18-12132 rear). Press out the old ones, press in the new ones and ream to fit. CAUTION: do not try this unless you have a press & know how to use it. If you break the base, a new one costs $130. If you bend the tower which holds the front bushing, a new plate will cost you $30. Resist the temptation to buy a new plate; most are pot metal and the threads will wallow out about the third time you change the points.

2. Take the new bushings and distributor to your local machine shop.

3. Send the distributor out for bushing replacement if you do not have a local machine shop
75 Tips
 

Thank you kindly Bruce, I have seen that list of operations many o' times.
I don't mean to sound cruel or harsh, but that was not what i asked for. I asked if i could do a continuity check to test the whole system or if the points open/closing would prevent that and what the amount of voltage going to the coil should be.
I do appreciate you assistance though.
 
(quoted from post at 11:04:01 11/22/17)
Thank you kindly Bruce, I have seen that list of operations many o' times.
I don't mean to sound cruel or harsh, but that was not what i asked for. I asked if i could do a continuity check to test the whole system or if the points open/closing would prevent that and what the amount of voltage going to the coil should be.
I do appreciate you assistance though.
o, you can not do continuity test as you describe. Running voltage to coil means only that points are opening and closing, which you already know since it is running. Meaningful coil input voltages are with points open and also with points closed, not running.
 

Okay, so test is a no-go.
Now, I'm not entirely sure I understand that last part 100% My tractor does not run, it will crank but not fire.
Are you saying that since the wire at the top of my coil has voltage to it, that the points are opening/closing?
 
(quoted from post at 09:04:01 11/22/17)
Thank you kindly Bruce, I have seen that list of operations many o' times.
I don't mean to sound cruel or harsh, but that was not what i asked for. I asked if i could do a continuity check to test the whole system or if the points open/closing would prevent that and what the amount of voltage going to the coil should be.
I do appreciate you assistance though.

like JMOR said, NO. you can check from switch to the coil tho.
I would put a 12 volt coil on it. that way all you need is the original ballast resistor. make sure it is wired like it shows in JMOR's wiring diagram. google is your friend.

google how a coil works, there is no connection between the primary low voltage and the high spark out put. it is all done with magnetic fields.
have fun
 
(quoted from post at 11:23:26 11/22/17)
Okay, so test is a no-go.
Now, I'm not entirely sure I understand that last part 100% My tractor does not run, it will crank but not fire.
Are you saying that since the wire at the top of my coil has voltage to it, that the points are opening/closing?
he 3 to 5 volts is an "indication" that points are opening and closing as you rotate engine with starter, but not a certainty. Measure the voltage at top of coil as you 'bump' starter for fraction of second at a time & if points are opening & closing, when they open you read battery voltage (12) and when closed , some lesser voltage (x).
 
you can't do a continuity check while the circuit is powered, you can't do a continuity check past the distribuitor cap in any
case.. there are AIR GAPS involved.

put a test lamp in line with the coil.. key on.. crank over.. lamp should blink.

if it does, try running a hot wire to the top of the coil and crank over.. see if you get spark.

ps.. if you are getting 3-5v at the coil top you have a major problem. the voltage at the coil top should alternate between
battery voltage and resistor drop voltage. 3v is a hair low.. I like to see 3.5v.. however.. the 5v is WRONG.. it should be
battery volts.. on a 6v system that is 6.2-6.3 v. if yours reads 5v, your battery is either dead.. or you have some very bad
wiring in that open circuit.
 
(quoted from post at 11:50:20 11/22/17) So even if it is a 12v system getting 4v and higher to the coil is bad?
Thank you for your input!
2v or battery voltage is correct to top of coil WHEN points are open.
 
Ah! okay.
If battery is goofed, but hooked up to jumper cables on a 12v 3/4 ton diesel truck, will that be sufficient? My battery is manure, but i dont want to get a new one, just to wear it down trying to start a tractor that wont start.
 
(quoted from post at 11:59:09 11/22/17) Ah! okay.
If battery is goofed, but hooked up to jumper cables on a 12v 3/4 ton diesel truck, will that be sufficient? My battery is manure, but i dont want to get a new one, just to wear it down trying to start a tractor that wont start.
ost jumper cables are of insufficient gauge wire to start a vehicle with a completely dead battery, but if your cables are good enough to spin the engine well, then yes, that is ok to do what you want.
 
The cables I have are heavy duty cables due to if my batteries die on my diesel truck, i need a lot of juice to get it going.
I was researching and saw that a group 26 battery is recommended? any merit to that?
 
(quoted from post at 13:39:37 11/22/17) The cables I have are heavy duty cables due to if my batteries die on my diesel truck, i need a lot of juice to get it going.
I was researching and saw that a group 26 battery is recommended? any merit to that?
ld Ns spin so easily on 12v that nearly any battery will get the job done.
 
Alrighty, well I ordered a tune up kit and for it since the plugs looks like someone dipped them in tar along with all the plug wire are raggity. Ill swing a battery in it then let ya know! Thank you for the help you've supplied.
 
kyle.........letts play the odds here, $38 coil is probably the 12-volt coil. Howsomevers, BOTH need the same infamous ballast resistor. Fords trick fer weak knee 6-volt batterys. Now daze, ya kenn buy hairy chested Die-Hards. Surprizingly enuff, 6-or-12 volt, BOTH use the same points (0.015) and same condenser (200-volt) Just the primary's are different; secondarys are the same. How to tell the difference? Lable on the box. Iff'n ya lost the box, you kenn use your magic ohm-meter. 6-volt will be about 1-1/2 ohm and 12-volt will be about 4-ohms. Final remark, digital meters don't like sparkies from running tractor engines ...but... they work good when engine is NOT RUNNING. HTH, Dell former calibration lab engineer fer Boeing Co
 
Thank you dell, both of the coils were 12v one looks like a standard 12v square coil, other is a cylindrical 12v coil.
You worked for boeing? My stepdad used to/still works for them. Had me a job lined up there if i did 4yrs army as a helicopter mechanic. Decided tp be a bradley mechanic due to living situations. Thank u for the input!
 
kyle.......yeah, I wuz a flight test engr that rode in the back of the airplane studying the effects of vibration on airplane parts with accelerometers. People gitt excited when parts fall off, eh?.......wideband Dell
 

I had to look dat up ( bradley)... Think of the points (contact set) as a switch and the coil a headlight bulb like the coil the bulb adds resistance to a closed circuit. If you measure across the power supply side and the ground (points closed) the voltage with be the voltage drop (lost voltage).

Why do you lose voltage measuring the the voltage on the top of the coil with the points closed (pulled to ground) its the resistance in the circuit coil and any resistor added to the circuit.

I don't put much faith in voltage checks unless I know its loaded. On the table I just use a H6054 headlight bulb wired in place of the coil if its off points open and on very bright points closed I move on with life... Ohm readings are a good place to start but I don't live and die with them...

Why I think ft mt's are a P.O.S. is zackly this reason you have to remove the dist. to much of anything to them... I don't find this EZ they all should be ground up into sausage.
 
That is a good way of thinking about it. yeah ive seen a lot of distaste for the front mounted ones.
Where about in NC are you from? Born an raised in jacksonville on the coast. right outside camp lejune.
 

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