2N Runs 30-60 Then Quits

JonV

Member
46 2N, runs fine, but after about 30min to an hour under load (plowing, brush hogging, etc...) it suddenly starts sputtering like its missing on a cylinder then completely dies a few seconds later. I can turn it over as much as I want after that and it won't start. So I checked the plugs and it has spark, cracked the fuel line at the top of the carb and it has fuel there. The fuel line was very hot, as was the carb bowl. So I'm wondering if that being so warm is causing a vapor lock or some other fuel problem internally within the carb or just what the problem is? Any thoughts? A friend thought maybe the intake air was getting too hot. I could do some more trial and error, but I know some of you have seen practically every N problem in the book. Would greatly appreciate the help. Thanks.
 

Forgot to add that once completely cool, usually the next day, it'll start and run great, but repeat the same problem.
 
There are a few things that could be causing your problem & vapor lock isn't one of them. In order to vapor lock, you need a fuel pump. Yes, it can vacuum lock or the ethanol in the gas could boil, but it won't vapor lock.

It is important for you to tell us if your tractor has a 6 volt or 12 volt electrical system. The troubleshooting is different based upon the configuration of your engine.

It takes three things for an engine to run: spark at the right time, compression, & fuel/air in the right mixture. For the moment, forget about compression & concentrate on narrowing the problem down to spark or fuel.

There are three very important tools you always need to have in your N tool box: a 3 inch piece of wire w/ alligator clips on each end, a spark checker w/ an adjustable gap (* see below) and a 7/16 box end wrench. (see tip # 50 at the link below) And, you really do need a working ammeter on the tractor; it is a very important diagnostic tool. With these tools, you can quickly narrow down most N problems to spark or fuel.

As soon as it stops running (not 5 minutes later), check for spark then fuel. First, turn the key on, crank the engine & look at the ammeter. What is the needle doing? Does it show a constant discharge, no movement at all, or does it move back & forth slightly? Next, 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....because the likely suspect would be the coil (and do not forget to turn the ignition switch off; see tip # 38 )

Next, 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)

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
 
Caveat: I am not an expert and would never pretend to be. That said, I bought a 1950 side-distributor N with original 6-volt a few years ago. It started and ran beautifully, but after a few weeks it would start and work great for about half an hour, then quit and refuse to start until the next day. I can't remember exactly how, but I discovered a bad key switch. (As I recall, I was checking the wiring and found the switch wiring was really hot; jumping across the switch let it start.) I put in a new switch and haven't had a problem since. This probably has nothing to do with your problem, but FWIW it's what happened to me. Good luck with your issue.
 
JonV.....ya gotta BAD square can 4-nipple ignition coil. REPLACE IT!!!!.....Dell, yer self-appointed sparkie-meister

BTW......it takes about 1-hr fer yer square can coil to melt the insulative tar inside the coil and cause it to miss
 
(quoted from post at 19:41:45 06/24/17) JonV.....ya gotta BAD square can 4-nipple ignition coil. REPLACE IT!!!!.....Dell, yer self-appointed sparkie-meister

BTW......it takes about 1-hr fer yer square can coil to melt the insulative tar inside the coil and cause it to miss

Thanks for all the advise. It has been converted to 12v. I thought since I saw spark that wasn't the problem, but it probably isn't putting enough juice out or is randomly sparking. It did the same thing last evening and I pulled the air cleaner tube and stuck my hand over the carb. Plenty of fuel and still nothing, so I'd place my money on you being correct Dell. I'll do some more quick tests as you mentioned Bruce. I've been thinking of just doing the coil conversion for a while anyway. Is it worth it or better to just stick with the 12v square? Thanks again
 
Fixed! Again, I just want to say thanks for all the help. I ended up replacing the coil and brush hogged today without any trouble. How come those coils don't seem to hold up well. I think this is the 3rd one now.
 
(quoted from post at 04:25:51 07/06/17) Fixed! Again, I just want to say thanks for all the help. I ended up replacing the coil and brush hogged today without any trouble. How come those coils don't seem to hold up well. I think this is the 3rd one now.

Well, not even a year later and it's happening all over again. I'm almost positive its the same thing, and this would be coil 4 (only I pretty much refuse to put another one of those square can in). Dell, I seem to recall seeing a post from you a while back on how to do a round coil conversion, or maybe it was some else. Is it pretty straight forward? I've looked into a little. Which coil would be best? Thanks.
 
(quoted from post at 21:49:07 05/26/18)
(quoted from post at 04:25:51 07/06/17) Fixed! Again, I just want to say thanks for all the help. I ended up replacing the coil and brush hogged today without any trouble. How come those coils don't seem to hold up well. I think this is the 3rd one now.

Well, not even a year later and it's happening all over again. I'm almost positive its the same thing, and this would be coil 4 (only I pretty much refuse to put another one of those square can in). Dell, I seem to recall seeing a post from you a while back on how to do a round coil conversion, or maybe it was some else. Is it pretty straight forward? I've looked into a little. Which coil would be best? Thanks.
Dell is no longer with us. God rest his soul.
There are plenty of posts in the archives about how to convert the coil though.
Pertronix sells a complete kit to do exactly that including electronic ignition if your tractor is converter to 12V.

In the 6-8 years I owned my 9N 6V and 2N 12V I never had a coil fail. I guess I was lucky.
Are you using the original wire wound ballast resistor on the back of the dash?
 
(quoted from post at 05:.
n the 6-8 years I owned my 9N 6V and 2N 12V I never had a coil fail. I guess I was lucky.
Are you using the original wire wound ballast resistor on the back of the dash?[/quote]

I believe the ballast resistor is connected, but I’ll have to double check now that you mention it. Seems awful strange to go through so many. I did notice the fins on my radiator are bent directly inline with the coil (maybe this is causing enough of an airflow issue to cause overheating of the square can?) As far as the conversion goes, I know everyone tends to use the IC14SB, but couldn’t any 12v be used?
 
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I have EI and just rolled my own used the IC14SB coil with out resister.

Don't now way pictures from phone are sideways.
 
"everyone tends to use the IC14SB, but couldn’t any 12v be used?"

Yes, any equivalent 12V coil meant for use without an external
resistor should be an acceptable substitute for the NAPA brand.
NAPA here is about $20, the Carquest next door is about $15.
Prices do vary by location though.
 
(quoted from post at 23:25:18 05/27/18) "everyone tends to use the IC14SB, but couldn’t any 12v be used?"

Yes, any equivalent 12V coil meant for use without an external
resistor should be an acceptable substitute for the NAPA brand.
NAPA here is about $20, the Carquest next door is about $15.
Prices do vary by location though.

I picked up the coil and have the old square can soaking in gas. Hoping to get it converted over later today. So I can just connect the old coil wire up to the + on the new one right? And I then need to jump the resistor too correct? If someone can confirm what I need to do in regard to the resistor I'd greatly appreciate it. Thanks.
 
So before switching over to the new coil I decided to find a proper wiring diagram and see if anything was wired wrong to begin with. My wiring was definitely not how it should be, but I'm not sure if it would cause my problem. Maybe the #1 alt wire being directly in connection with the coil wire could cause some issues, but I have no clue. If any of you guys more knowledgable with this sort of thing could take a peek, and let me know your thoughts, I'd appreciate it. I wired everything correct know, but haven't run it long enough to see if it's fine or not. First pic is how it was, and second is how it should be according to JMORs pictograms on the NTC site.
 
Update...

Well, I ran it for a good 2hrs and think it ran about as smooth as I've ever heard it. Use to give an occasional light pop here and there from the exhaust. I also put it under load plowing and discing for 2/3 of that time and it never quit on me. So it appears rewiring solved my problems without switching coils. Would still be curious what was happening with the other wiring scheme, if anyone knows. Oh, and for full disclosure, I also replaced the fan belt which was slipping/squealing at full throttle this season (doubt if this was causing too many issues, as the battery was always well charged. But I'm sure it's got a bit more juice wide open now). Hope this helps someone else in the future, and thanks JMOR for the great diagrams!
 

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