52 8N Died suddenly. Won't restart

Kenster

Member
52 8N. It ain't pretty but always starts right up and runs great.
A couple of times lately after it has run a while it won't restart. Turns over great but won't fire off. I've let it sit for a couple of hours and it fires right up.

I bushhogged a very thick meadow for over four hours yesterday and it never missed a beat. This morning, I was mowing for maybe 15 minutes and it just died. No surging or coughing and it wasn't bogging down in the thick grass.

I tried to restart. It turns over great but, again, won't fire off.
Gas tank had just been filled this morning with fresh fuel. All the cables are in place.

I do notice that the gas cap has condensation on the outside which I think is strange as it is very hot here. The cap was bone dry when I filled up this morning.

Coil heating up and melting the insides? I thought that was a front mount, square box issue.

Vapor lock?

Thoughts, please!
 
(quoted from post at 12:26:34 07/21/15) 52 8N. It ain't pretty but always starts right up and runs great.
A couple of times lately after it has run a while it won't restart. Turns over great but won't fire off. I've let it sit for a couple of hours and it fires right up.

I bushhogged a very thick meadow for over four hours yesterday and it never missed a beat. This morning, I was mowing for maybe 15 minutes and it just died. No surging or coughing and it wasn't bogging down in the thick grass.

I tried to restart. It turns over great but, again, won't fire off.
Gas tank had just been filled this morning with fresh fuel. All the cables are in place.

I do notice that the gas cap has condensation on the outside which I think is strange as it is very hot here. The cap was bone dry when I filled up this morning.

Distributor heating up and melting the insides? I thought that was a front mount, square box issue.

Vapor lock?

Thoughts, please!

To paraphrase the Borg: [i:fc797872fc][b:fc797872fc]Guessing is futile - you will be frustrated.[/b:fc797872fc][/i:fc797872fc]

Problems like this get solved by methodical diagnostics not guessing. Step one is to check for the basics - like a good strong spark at the plugs.

TOH
 
Trouble shooting 101 is needed.
#1 Check that you have a good blue white spark that jumps a 1/4 inch gap at all 4 plug wires. If you that then go to 2
#2 pull the carb drain plug and make sure you have a good steady flow of gas from that drain plug. Catch the gas to make sure it is not full of water/dirt/rust.
Then post back what you find.
If no spark try a hot wire from the battery ignition side to the ignition side of the coil. If it fires up you have a wiring problem from the coil back to the battery. If still no spark hot wired your problem is in the distributor.
No gas flow work you way back till you find where it get stopped at
 

I'm hoping it will do as before and start up after it sits for a while, allowing me to get it out of the meadow and back up to the house for my diagnostics.

Is the condensation on the gas cap significant? Haven't ever seen that before.

I'll post back.

Thanks.
 
As others are saying, don't guess. Troubleshoot the problem. 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. Jumping ahead to 'so-and-so said it could be whatever' or just replacing parts usually just wastes your time and your money.

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.

Next time it stops, check quickly for fuel (** see below) then spark. When I say quickly, I mean get off the seat, grab the tools & do it right then. Do not wait a minute or two. First, 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. Let it run for at least 30 seconds. 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. So, next, 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 ¼” 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)

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. Check the screen in the elbow & 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 ¼” 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 ¼” will work. Ground it to a rust & paint free spot on the engine turn the key on & look for a spark.

** On most gas engines, you would check for spark first. But, the N gas tank has a pin-hole size vent that easily clogs, causing vacuum lock. By the time you check for spark on a hot engine, the vacuum lock will dissipate w/ the engine off
75 Tips
 
That is why I said catch the gas to look for water etc. This new gas absorbs water out of the air and can cause a water problem in the carb
 
Kenster.........yer "dies and re-starts after several hours" is typical of VACUUM in yer fuel tank from CLOGGED breather hole in dome of tank at front. Mud daubers like to clog the breather hole and as yer engine uses up the fuel it creates a VACUUM that gravity won't overcome and engine dies. They make a NEW breathing gascap fer NAA-600. ($20, cheap) As fer yer "suddenly dies" complaint, that is ALWAYS electrical. Loose connection somewhere. .......HTH, Dell
 
Well.... that was easy. I trekked back out to the meadow with a 7/16" wrench in my pocket. The first thing I did was pull the plug on the bottom of the carb. I got a good flow into a clear bottle. No water. No debris.

So, I started looking at the wiring. All the cables and plugs were in place good'n'tight. I began to check all the other wires for loose connections.

Lo and Behold... one of the wires on the two wire alternator bar had just slipped off. Probably knocked of by the head high brush I've been mowing.

Slipped it back on and... Houston we have ignition. However, it's now almost 100 degrees outside so I brought it back to the house and will wait until later this evening to get another couple of hours in.

Thanks for everything.
 

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