2N won't start

Leroy Ahlers

New User
I am about to give up. The tractor started running rough a few months ago, then rougher and then would not start. I drained and flushed the gas tank. It had some water in it. Cleaned gas filters. Put on new sediment bulb. Put on new points and plugs and condenser. Put on new zenith carb. I have gas at the carb. I have spark although it may be weaker than it should be. It still won"t fire at all. Makes no attempt to start. The plugs are totally dry. Should they not be wet with fuel after repeatedly trying to start it?? It started really good until it started running rough a few months back. I have no idea what else to try.
 
If the plugs are wet with fuel, that means you flooded it & the plugs are fouled. You never want to see wet plugs.

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.

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, an old spark plug w/ the gap opened to 3/16” and a 7/16 box end wrench. And, you really do need a working ammeter. With these tools, you can quickly narrow down most N problems to spark or fuel.

First, check for fuel. 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. 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, crank the engine & look at the ammeter. What is the ammeter doing? Does it show a constant discharge, no movement at all, or does it dip? Next, get the old plug, ground it to a rust & paint free spot on the engine, turn the key on & crank the engine. If the spark jumps the 3/16” gap, you probably don’t have a spark problem. If it won’t jump the 3/16” gap, you have a spark problem. If the ammeter 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 does not have gas coming out of the carb at a steady stream w/ the bolt out, 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, 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.

Post back w/ results or more questions.
50 Tips
 
It has a 12 volt conversion and alternator. But I ask again should the plugs not at least be damp after repeatedly trying to start it?
 
(quoted from post at 18:30:24 03/12/09) It has a 12 volt conversion and alternator. But I ask again should the plugs not at least be damp after repeatedly trying to start it?

If they are gassed (flooded) they could be wet.

A carb is supposed to "vaporize" the fuel, and get it to go in as a vapor.

Wet plugs, most of the time are fouled.

Take them out and dry them off, heat the spark end pretty hot with a propane torch.

If you are positive that you have NO gas leaks anywhere....I have took a propane torch and heated my manifold to get my tractor to not flood in cold weather, and to crank easier..
 
Sounds like a lack of vacuum to me. Have you tried placing your hand over the carburetor air intake throat while cranking the engine? Should "suck" on your hand. If no suction, I would recommend a compression test-- you may have valves not seating or badly worn rings. Another consideration would be a leaky intake manifold--ie--a bad gasket or a hole rusted through somewhere.
 
I checked the compression at the carb. It sucks on the hand real well. Plugs are still totally dry which doesn't seem right to me but I'm not an expert on updraft carbs so maybe they should be dry. Plenty of gas at carb and spark at plugs so I am mystified. Thanks for your advice because I thought as old as it is compression could sure be an issue.
 
put a teaspoon of gas in each cylinder then try to start it if you have plenty of spark. if plugs are dry, then your carb could be clogged up bad gas and water will do that. i had a lawn mower with watery gas runned terribly then died. drained the gas and sprayed carb cleaner through then filled with gas. ran rough then straightened up and added STP carb and fuel cleaner to it still running today. that stuff really works good.........
 
Yesterday's Tractor Forums

We sell tractor parts! We have the parts you need to repair your tractor - the right parts. Our low prices and years of research make us your best choice when you need parts. Shop Online Today.

Back
Top