I started up my 8N this year to move it, wasn"t running the best but didn"t think much about it. Now it won"t start at all. It would start and run badly for about 30 seconds, now wnnnnnnn, wnnnnnnn, nothing. It was leaking gas out of the carb, so i rebuilt it, same thing. so i replaced the carburator, same thing. I have also replaced the battery, battery cables, fuel filter, ignition coil, points, condensor, plugs, plug wires. I double checked to make sure i had the right firing order, 1243. I think the spark plug wires i have might be junk, but i would think it would at least try and start. Please help.
old
Well-known Member
- Location
- Camdenton Missouri
More info needed to help you much. Front or side mount distributor??
1st thing to check is spark and it needs to be a blue/white in color and jump a 1/4 inch gap or more.
2nd check your plugs they could be gas fouled and if they are it will not run.
3rd fuel filter??? If it has an in line filter that could also be the problem in line filters and gravity flow fuel systems do not work well
1st thing to check is spark and it needs to be a blue/white in color and jump a 1/4 inch gap or more.
2nd check your plugs they could be gas fouled and if they are it will not run.
3rd fuel filter??? If it has an in line filter that could also be the problem in line filters and gravity flow fuel systems do not work well
Bruce (VA)
Well-known Member
Each time you ask a question here, we always need to know at least 3 critical pieces of information:
1. What model tractor (2N, 9N, 8N, NAA, etc)?
2. Is it 6v or 12v?
3. Is the distributor on the front or side of the engine?
Troubleshooting is different depending on the model of the tractor, voltage & distributor placement.
And, even if you told us that last week, remember that you’re dealing w/ a bunch of guys w/ CRS.
All we know is that you have an 8N. And, that despite nearly rebuilding the tractor one part at a time, it still doesn't run. That's because you violated Rule 1 of Tractor Repair: Figure out the problem before you start replacing parts. It takes three things for an engine to run: spark at the right time, compression, & fuel in the right mixture. For the moment, forget about compression & concentrate on narrowing the problem to fuel or spark. If you don’t do that, you are going to end up chasing your tail around that tractor & spending a boatload of money to fix what could easily be a loose wire or bad ignition switch.
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 at least 3/16” ( ¼” is better) 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 doesn’t have spark after you jump the ignition switch, post back for more info on further troubleshooting.
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, & 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.
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 bolt in the bottom of the carb is the way to do it. 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, so that's why you need to use a spark plug. Or, a store bought plug checker. Remember, it’s 14psi outside of the engine & about 90psi at a 6:1 compression ratio in the cylinders & compressed air crates electrical resistance, so you really need the 17-22kv to fire the plugs when the engine is running. There are other good ways to check for fuel & spark, but these ways work for me.
50 Tips
1. What model tractor (2N, 9N, 8N, NAA, etc)?
2. Is it 6v or 12v?
3. Is the distributor on the front or side of the engine?
Troubleshooting is different depending on the model of the tractor, voltage & distributor placement.
And, even if you told us that last week, remember that you’re dealing w/ a bunch of guys w/ CRS.
All we know is that you have an 8N. And, that despite nearly rebuilding the tractor one part at a time, it still doesn't run. That's because you violated Rule 1 of Tractor Repair: Figure out the problem before you start replacing parts. It takes three things for an engine to run: spark at the right time, compression, & fuel in the right mixture. For the moment, forget about compression & concentrate on narrowing the problem to fuel or spark. If you don’t do that, you are going to end up chasing your tail around that tractor & spending a boatload of money to fix what could easily be a loose wire or bad ignition switch.
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 at least 3/16” ( ¼” is better) 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 doesn’t have spark after you jump the ignition switch, post back for more info on further troubleshooting.
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, & 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.
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 bolt in the bottom of the carb is the way to do it. 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, so that's why you need to use a spark plug. Or, a store bought plug checker. Remember, it’s 14psi outside of the engine & about 90psi at a 6:1 compression ratio in the cylinders & compressed air crates electrical resistance, so you really need the 17-22kv to fire the plugs when the engine is running. There are other good ways to check for fuel & spark, but these ways work for me.
50 Tips
Bruce,
Thank you for all the information. It will take me a bit to go through it all. I know i shouldn't have replaced everything but not being a mechanic i thought it looked like everything probably needed replacing anyway. It is an 8N with a front mount distributer, converted over to a 12v. Last year it was a loose battery cable i found after replacing the battery and the starter. As far as my new problems, After removing the drain plug from the carb i have fuel draining until i replace it or shut off the fuel valve so i'm assuming it isn't a fuel problem. When i crank it over the ammeter appears to jiggle back and forth. I am now going out to check the spark.
Thank you,
Darren.
Thank you for all the information. It will take me a bit to go through it all. I know i shouldn't have replaced everything but not being a mechanic i thought it looked like everything probably needed replacing anyway. It is an 8N with a front mount distributer, converted over to a 12v. Last year it was a loose battery cable i found after replacing the battery and the starter. As far as my new problems, After removing the drain plug from the carb i have fuel draining until i replace it or shut off the fuel valve so i'm assuming it isn't a fuel problem. When i crank it over the ammeter appears to jiggle back and forth. I am now going out to check the spark.
Thank you,
Darren.
Bruce (VA)
Well-known Member
First, make 100% sure you have battery voltage to the top of the coil. If you don't, stop right there & let us know. If you have battery voltage at the top of the coil (points open; half that if closed) then the problem is in the distributor.
Assuming that the bushings & advance weights are ok, the most common electrical failure (no spark, weak spark) points on the frontmount are:
1. The insulator under the concave head screw.
2. The insulator at the end of the points where the copper strip attaches.
3. The copper strip grounded to the plate.
4. The condenser wire grounding.
5. The pigtail/tab not making contact.
6. Incorrect positioning of the spring clip on the plate causing the pigtail to ground.
7. Incorrect seating of the coil on the distributor.
8. Water/moisture inside the cap due to gasket failure or the absence of a gasket.
Order a new set of gaskets.
Remove the distributor from the tractor.
Dress the points by running some card stock or brown paper bag through them.
Then, do a continuity check.
First, make sure your meter/light works (don't ask....)
Now, 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. Coil on, 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!
Post back w/ more questions or results.
50 Tips
Assuming that the bushings & advance weights are ok, the most common electrical failure (no spark, weak spark) points on the frontmount are:
1. The insulator under the concave head screw.
2. The insulator at the end of the points where the copper strip attaches.
3. The copper strip grounded to the plate.
4. The condenser wire grounding.
5. The pigtail/tab not making contact.
6. Incorrect positioning of the spring clip on the plate causing the pigtail to ground.
7. Incorrect seating of the coil on the distributor.
8. Water/moisture inside the cap due to gasket failure or the absence of a gasket.
Order a new set of gaskets.
Remove the distributor from the tractor.
Dress the points by running some card stock or brown paper bag through them.
Then, do a continuity check.
First, make sure your meter/light works (don't ask....)
Now, 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. Coil on, 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!
Post back w/ more questions or results.
50 Tips
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