@n still wont start

stryped

Member
I have been working on this thing off and on for over a year and the thing is still not running. I started into it last year hoping to be able to use it as a plow for my driveway. I still can not start it. To make it what I thought would be more reliable, I replaced the following: gas tank, spark plug wires, spark plugs, distributor (I broke the tang on my old one), coil, points, fuel bowel, etc. I checked the timing twice.

I rebuilt the carb and installed it this weekend. It started for a minute holding the choke in but then backfired and died and could not restart. (The few times I have gotten it to run in the last year it would run for a minute then backfire violently and not be able to restart). I bought a new carb from TSC as a last ditch effort yesterday. Still no start. Using an old spark plug yesterday grounded to the engine it does fire. If I crank on it long enough it acts like it fires for a split second because the starter disengages but never takes off. I can feel suction on the throat of the carb when cranking, however, I am not so sure the spark plugs are getting gas. It will not start when spraying starting fluid in the throat of the carb. I don't think spraying starting fluid in one of the spark plug holes and reinstalling the spark plug made a difference either.

As a last ditch effort, I checked compression with the throttle control wide open and no choke. Of course the engine was cold as I can not get it started. The following were the results I obtained:
1= 85psi
2= almost 90 psi
3= almost 90 psi
4= almost 80 psi

I then added 5w30 (all I had) motor oil into the spark plug holes one at a time. I probably used too much as I poured from a quart container, the space was tight, and it was getting dark. The following readings were obtained after the addition of oil:
1= 120 psi
2= 130 psi
3= 105 psi
4= 95 psi

I did notice after doing the wet test, oil was coming out of the carb throat.

I replaced the intake exhaust gasket last year because it had a leak.

I am just so frustrated and not sure what to do at this point.
 
One other thing, probably unrelated, but what is the center bolt and nut on the intake/exhaust manifold for? I took it out, and screwed it in some, it made no difference. It seems I have seen other intakes for this tractor that did not have this bolt/nut.
 
A couple of observations:
1. Your compression is a little low.
2. The center fitting in the manifold is a vacuum port. There was a vacuum milker that attached to that port. Make sure the fitting is all the way back in and not leaking.
 
6 volt or 12 volt?

Front or side distributor?

There are two schools of thought when it comes to getting a non-running tractor to start. One way is to just start replacing every part you can get to until it starts or you run out of money. The other way is to take a step-by-step approach to solving the problem, working from most likely to least likely. The trick to fixing these tractors (or trouble shooting any piece of equipment) is to be systematic about it. You need to isolate the problem step by step and work from most likely to least likely.

After all those parts bought & time & money invested, you still do not know if you have a spark or fuel problem.

" it fires for a split second because the starter disengages but never takes off."

That tells me that you have a spark problem.

Put your battery on a charger. (see tip # 60)

You need a strong battery to:

1. Close the solenoid

2. Spin the starter

3. Engage the bendix

4. Provide voltage to the coil.

As the battery gets weaker, the first thing to fail is your spark. If the battery is almost totally dead, all you will hear is the solenoid clicking.

In addition to charging the battery, chances are you need new cables as well (tip # 41). And, don't forget to clean all the grounds, to include the mating area between the starter & the block.

The more current you use to spin the starter, the less you have for the ignition.

While you are waiting for the battery to charge, check for fuel. Get a can & put it under the carb. Remove the bolt in the bottom of the carb; as long as the fuel is turned on, you should see gas flowing out of the carb. It should fill a pint jar in less than 2 minutes. If it?s a dribble, or runs for 5 seconds & stops, or none at all, you have solved half the problem: it?s fuel related. If gas flows well out of the carb & only stops when you turn it off at the sediment bowl, chances are very good it?s not a fuel problem. If it does not have gas coming out of the carb at a steady stream w/ the bolt out for at least 30 seconds, you have a fuel problem. First, remove the gas cap. Your vent could be clogged & it vacuum locked. If that doesn?t work, tap the carb bowl w/ a hammer handle in case the float is sticking closed. (don?t whack it w/ the head of the hammer; you can crack the bowl). If you still don?t see gas flowing, the N has three fuel screens; one in the brass elbow, one in the top of the sediment bowl & one on the stem of the sediment bowl in the gas tank. (see tip # 45) Check the screen in the elbow (see tip # 56) & the screen in the top of the sediment bowl. (don?t worry about the one in the tank) Both probably need to be cleaned. If you have the fuel knob turned on all the way, & 1 gallon or less in the tank, it may be trying to feed off of the reserve inlet which is probably clogged. Only open it 2 full turns. Put at least 2 gallons in the tank. (and do not forget to turn the gas off; see tip # 9)

After the battery is charged, hook up your spark checker*, turn the key on & crank the engine. If the spark jumps the 1/4? gap, you probably don?t have a spark problem. If it won?t jump the ?? gap, you have a spark problem. If the ammeter needle shows a constant discharge, or doesn?t move at all, that also tells you that you have a spark problem. Jump the ignition switch w/ your jumper wire & see what happens. If it runs, you found the problem. If it doesn?t have spark after you jump the ignition switch, post back for more info on further troubleshooting. (and do not forget to turn the ignition switch off; see tip # 38 )

There are ways to check for spark & fuel that work & ways that don't. For example, having gas to the carb is nice, but having it past the float is what counts! That?s why removing the 7/16? bolt in the bottom of the carb is the way to check for fuel. And, same thing w/ spark at the plugs. Some folks think that checking for spark means pulling a plug wire off & looking for one. Well, it's the distance the spark jumps at the plug that gives you the info you want. It takes about 17kv to jump a 3/16" gap & 22kv to jump ?? in the open air. Remember, it?s 14psi outside of the engine & about 90psi at a 6:1 compression ratio in the cylinders & compressed air creates electrical resistance, so you really need the 17-22kv to fire the plugs when the engine is running. A store bought plug checker (in the picture) will work better than an old plug because it won?t shock the snot out of you like an old plug might!

Post back with results or more questions.



*If you don?t own a spark checker w/ an adjustable gap, buy one. In the meantime, an old spark plug w/ the gap opened to at least ?? will work. Ground it to a rust & paint free spot on the engine turn the key on & look for a spark.
75 Tips
 
The battery was on a charger and charged while I was doing all the tests before. (I even tried it on 40 amp setting for starting an engine).

The battery cables are new. I rewired the tractor last year. So all connections and grounds should be good. I did open the plug in the drain bowel of the carb. Fuel did flow out continuously for over a minute until I turned it off.

The spark plug I used to test was the one I pulled out of the tractor. (I again put new ones in yesterday).

About the only thing I did not do from your suggestions is widen the gap to 1/4 of an inch. (I used the standard plug gap for the tractor.
 
Would the low compression cause my problems and the severe backfiring it did in the past?

What exactly is a "vacuum milker"???
 

I am guessing that you are missing the rotor clip in the distributor. If this is the case, it causes slop in the rotor and in effect changes the timing on the engine to where it could cause a backfire.
 
Please answer my questions.

6 volt or 12 volt?

Front or side distributor?

It does not matter if you rewired the tractor yesterday, you have a textbook case of low ignition current. When you let off the starter, it wants to fire.

The low ignition is as a result of a dragging starter, weak battery or bad connections.

You have enough compression to start & run the tractor; compression isn't your problem.

I'll suggest (again) that you check the connections, charge the battery & check the spark at 1/4".

If that all checks out, then we can move on to a voltage drop test on your starter.
75 Tips
 
I am sorry I forgot one of your questions. It is a 12 volt. It is a front mount distributor. I am not sure what you mean by "when you let off the starter it wants to fire". Maybe I did not explain correctly. What I was trying to say is when continuously cranking it sounds as if the engine for a split second wants to fire because the starter/flywheel sounds like it "free wheels" if that makes sense. Also, a puff of smoke comes out of the exhaust at this time. (burning of the left over oil from the wet compression test I believe).
I will try to check the spark tonight. However, I did all the above tests with my battery charger on the battery. (and this is after the battery was fully charged).
 
stryped,

You say your tractor is 12 volts. Do you have a 6 volt coil or a 12 volt coil? You cant tell by looking. You have to check the resistance of the coil. I don't remember what each will read. If a 6 volt coil, you need the original ballast resistor and a 12 volt to 6 volt reducing resistor. If a 12 volt coil you still need the ballast resistor. As a QUICK test run a wire straight from the battery to the top post of the coil and see if it starts. If it does you have an electrical issue, but don't run it but 20-30 seconds.

Good luck,
Danny
 
It is a 12v coil. I actually ran a wire from the battery to the top of the coil yesterday as a test and it still did not start.
 
I fought getting mine started for 2 months, it finally came down to a bad condenser. I installed a new one and it started right up. I put the old back in, no run.
 
Just throwing things out here! On the bottom of the coil is a spring looking thing. Try stretching it some so it makes better contact in the distributor.
 
Never mind. I just saw your spark video. It looks like you are getting good spark. Have you tried pull starting it?
 
I didn't see much spark after 10 seconds.

Was that 1/4" gap?

Time to pull the distributor.

Assuming that the bushings & advance weights are ok (*see below), & that you have correct voltage to the coil (battery voltage with the points open and about half that with the points closed), the problem is in the distributor.

Once you get the distributor on the bench, the first thing you need to check is bushing wear. If the shaft has any sideways movement AT ALL, the bushings must be replaced. (*** see below).

The most common electrical failure (no spark, weak spark) points on the front mount are:
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
3. The copper strip is broken or grounded to the plate. (look very carefully for cracks & breaks).
4. The condenser wire grounding to the plate or side of the distributor.
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.)
6. 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)
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.
10. Burned rotor, cracked/carbon tracked cap.
After you 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.

* *NAPA part numbers:
? Points: FD-6769X
? Condenser: FD-71
? Rotor: FD-104
? Cap: FD-126

*** 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.
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
 
(quoted from post at 09:19:52 10/18/16) Did you have spark with the bad condenser???
you can have a spark with no condenser at all! It just won't be very strong........usually not enough to run.
 
Ok. What makes you think it is in the distributor if I am getting spark? The gap was as wide as I could get the electrode, it is close to 1/4.

By the way, this is a new distributor.
 
Did the video I posted look like I have a strong enough spark and at least let me eliminate the condenser as a possible problem?
 
What makes me think it's in the distributor?

Two things.

First, I saw your video. I saw about 7 sparks. None at all after 10 seconds

Secondly, you have battery voltage to the coil and no spark at the plugs. If the problem isn't in the distributor, where is it?
75 Tips
 
I think you may be right but it was dark and I'm not sure if I was holding the camera right over the spark during those 10 seconds but shouldn't the engine have tried to start when it was sparking just curious.
I am going to try to pull the distributor and do the tests you say just trying to get a better understanding one thing I wanted to ask where is the best place to put the battery ground on this tractor it has always been on the dash and when I redid the wiring I reconnected it that way but first roughed up the area really good with a wire brush also should there be a ground strap on the head I have seen pictures of others that had a strap on the head similar to the way a car engine is grounded sometimes to the firewall I did not know if this was a requirement or not
 

"should there be a ground strap on the head I have seen pictures of others that had a strap on the head similar to the way a car engine is grounded sometimes to the firewall I did not know if this was a requirement or not"

definitely not a requirement, but i don't see where any harm could come from having one. mine has the ground to the dashboard and no strap to the engine, and works fine.

i'm going to guess that the difference between a car and an N, in terms of grounding, is that in a car, the drive train is isolated from the frame with rubber mounts, whereas in an N, the drive train IS the frame.
 
"should there be a ground strap on the head I have seen pictures of others that had a strap on the head similar to the way a car engine is grounded sometimes to the firewall I did not know if this was a requirement or not"

No.

An 8N doesn't have rubber motor mounts.

The strap goes to the battery box. Just insure it's bare metal to bare metal.
DSC03815.jpg

75 Tips
 
I pulled the distributor and performed test 1 and 2. They checked out ok. I did not have the coil with me so the other tests I will perform tonight. Points looked good though and gap was still correct.

Everything still has me stumped.
 

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