# 8n won't start



## .netDude (Nov 26, 2004)

no spark from any plug or from the center wire of the distributor. All the wires seem to be ok (connected, not all in the best condition, though), what should I check next?

Last time it ran (2-3 months ago), it all of a sudden had almost no power and was very hard to start. Had to use starting fluid, and to get it back to the shed was slow and very low power.


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## Old Vet (Oct 15, 2006)

Check the condensior and points and see that they are properly set. Then go to the (thing that makes the spark) be it a magintio or a can't think of the name. One will be the cause.


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## Bearfootfarm (Jul 13, 2006)

Sounds like the ignition coil to me. I'd replace it and might as well do wires and points too. Then it should run like new for a few years


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## ColumbiaSC. (Nov 25, 2005)

Fire, Air and Fuel.
My Grandpa told me this, the 3 basic rules! 
Like 'OLD VET' said look down the FIRE side!
I don't know how to tell you how to check/change the coil but that is a start, with a meter it should have fire, then the wires, ECT.


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## Beeman (Dec 29, 2002)

.netDude said:


> no spark from any plug or from the center wire of the distributor. All the wires seem to be ok (connected, not all in the best condition, though), what should I check next?
> 
> Last time it ran (2-3 months ago), it all of a sudden had almost no power and was very hard to start. Had to use starting fluid, and to get it back to the shed was slow and very low power.


 Is this a side dist or frt. dist motor? Has it been converted to 12 V? Is it still a points ign. system? How are you checking for spark?

If there is no power from the coil wire you should begin by checking the primary side of the ign. Do you have a 12v test light? Ground one end of the test light and check the small wires leading to the ing coil with the ign turned on. You should have power to the wire leading to the coil. If there is no power there you have to trace back and see where you lose it, possibly the ign. switch or the ign. resistor. If you have power then connect the test light to the side of the coil that leads to the dist., this is the small wire that leads to the points. Observe the light while cranking the engine with the ign. on. The light should blink on and off as the engine cranks over indicating the points are working. If the light blinks and you have no spark you most likely have a bad ign. coil. If the light doesn't blink you most likely have a problem with the points.


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## agmantoo (May 23, 2003)

Front mounted distributors on red belly tractors are difficult to access and are odd for newbies to work on. If you remove the distributor make darn certain that you get the rotor positioned correctly when you remount it. The rotor will mount 180 degrees out. Since the tractor did run when started with starting fluid previously you did have spark at that time. With the description of how it ran back then the symptoms indicate a fuel delivery problem at that time. Now you have an electrical problem that IMO is nothing more than the points are oxidized from the tractor being parking for so long. With you lack of familiarity I suggest that you try to trade work with someone experienced on these tractors. If the tractor has a side mount distributor as the last built ones did you may have some luck working on it yourself. One a side mount distributor version just remove the distributor cap and with the switch on determine if you can get a small spark by opening and closing the points starting with the points in the closed position. If you get a spark there then substitute the coil. The coils available today for the front mount design distributor are a POS. They cannot tolerate heat and fail frequently. You can alter the front mount distributor and replace the old coil with a car coil from the 60's era. Even if the tractor is still 6 volts (which I doubt) you can use a 12 volt car coil.


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## .netDude (Nov 26, 2004)

Thanks for the reply's. 
It's a 6 volt side mounted distributor, I replaced the cap, condeser (I think), and plugs - it was an 8n tune up kit, and wires prior to the low power / no start event a couple months ago. 
To test for spark, I held the end of the spark plug wires close to the head and cranked the engine, same for the wire from the center of the distributor. 
How much $ is a coil (roughly)?



> Ground one end of the test light and check the small wires leading to the ing coil with the ign turned on. You should have power to the wire leading to the coil.





> One a side mount distributor version just remove the distributor cap and with the switch on determine if you can get a small spark by opening and closing the points starting with the points in the closed position. If you get a spark there then substitute the coil.


I removed the dist cap, rotor, plate that was under the rotor, and there's a small metal spring type thing that when pryed gently with a screwdriver, it did generate a spark.


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## jefferson (Nov 11, 2004)

Kick it !!!!


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## rambler (Jan 20, 2004)

Moisture in the distributor is always the killer for my tractors. is it good & dry, was it out in the rain or pressure washed? Just water vapor inside will ground it out.

Condensors go bad for me the most, & are about the cheapest to replace. Little tiny canister next to the points. Points might as well be replaced at the same time, you are right there... Check the gap on the points real careful, easy for that to be off even if you try hard - a couple 1000's off & it will have weak or poor spark. Dad had a new condensor be bad out of the box, took a bit to figure that out.......

The rotor (the spinny part on top) will wear down, and the distributor cap might crack. Shorts will follow the hairline crack in the cap, rather than go where they should.

My experience, coils last forever for me. Just never saw one fail. My 960 tractor(s) (used to have 2, now have one) the coils would get too hot because they were strapped tight against the block, no airflow, but when we put them on a 2" block of wood to move away from the heat of the block, the original coil is still there, we moved it 35 years ago.....

But, if the coil is bad, it is bad & needs replaced.

--->Paul


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## Old Vet (Oct 15, 2006)

A coil woundnot cost much. I havent price them latley but a 12 volt coil cost about $10. I usualy replace the coil along with points to make sure of it. Just make sure that the distributer cap is not crack or have moisture in it. Sounds like you have done the right thing except the coil.


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## Yankee1 (Dec 17, 2003)

If you have spark when opening the points with a screwdriver then you will need to adjust the point gap. double check after tightening it down to make sure it didn't move. For side mount dist the point gap will be .025


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## Windy in Kansas (Jun 16, 2002)

Columbia said:


> Fire, Air and Fuel.
> My Grandpa told me this, the 3 basic rules!


Your grandpa was correct but there is one more part to the equation that is absolutely needed for an engine to run. That missing part is compression on the fuel/air mixture. We have probably all heard the stories about someone shoving a potato into an exhaust pipe so that an engine will not start. 

Aside from not allowing the fuel/air mixture to be sucked through the manifold and into the cylinders it also doesn't allow for compression to take place hence the engine won't start. I've also heard of older vehicles parked for an extending time having exhaust ports plugged by wasp/mud dauber nests thus not allowing them to start.

When checking the points make sure that they are not worn so badly that they can't close. Also look at the cam follower to make sure it isn't worn so badly that the points can't open. Both rare cases of extreme wear. 

Also check to make sure that no wire is pinched in the distributor system which may ground it out. One model of Chevrolet was good at getting a wire pinched, might have been the condenser wire that would get in the way and pinched between the cap and housing.

Everyone has you on the right track and it should be an easy fix. Leaving a key or switch on can burn out a coil, otherwise they will often go for decades.


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## Beeman (Dec 29, 2002)

.netDude said:


> Thanks for the reply's.
> It's a 6 volt side mounted distributor, I replaced the cap, condeser (I think), and plugs - it was an 8n tune up kit, and wires prior to the low power / no start event a couple months ago.
> To test for spark, I held the end of the spark plug wires close to the head and cranked the engine, same for the wire from the center of the distributor.
> How much $ is a coil (roughly)?
> ...


 When you checked for spark did you remove the center wire from the cap and leave it connected to the coil and hold it close to the head and then check for spark? When you say you moved the metal spring type thing what sparked? Were you holding the heavy coil wire near the head and it sparked? Or was it the 12v at the spring type thing that sparked? These are 2 different circuits. Did you understand what I was describing to do with a test light? With the cap and rotor removed if you rotate the engine do the contact points open and close as the distributor rotates? Does the center of the distributor rotate?


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## .netDude (Nov 26, 2004)

I don't have a test light, but initially the spark was at the spring type thing, not from holding the center wire from the distributor next to the head. It looks like if the center of the distributor spins it puts pressure on this metal 'spring type thing', that causes 2 little round pieces of metal to make contact. Are these these the points? This is where I saw the spark. 
So, I took it apart again, made sure the rotor, the metal contacts inside the cap, and the metal on the cover under the rotor were all clean, dry, and free of corrosion, and I now have spark when holding a wire next to the head.


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## Windy in Kansas (Jun 16, 2002)

The two round contacts are the points. The entire spring, cam follower (rub block), base, and contacts are more properly called the point set. I don't know anyone that normally calls it that, shortened to points instead.

The opening and closing of the points causes an electric field within the coil to collapse thus increasing the voltage which of course allows for the greater spark. The distributor cam does the opening at closing at the appropriate time when adjusted properly. The points must close to allow the electrical field to build, then open for the aforementioned collapse. Having points in good condition and alignment allows the field to collapse properly and fully. On older units the points may be filed with a points file to renew the contact surface. It is best to use a proper points file for the task.

When the field collapses with the higher voltage it sends it through the center terminal of the coil. The coil wire sends it to the center tower of the distributor which in turn uses the rotor underneath the cap to distribute it to each spark plug wire.

The rotor must have a good contact on the end to take the spark to each wire as well as a good spring to make contact with the underside of the cap.
Corrosion will cover the rotor contact sometimes and sparking will wear the contact shorter. When a unit fails to start a brightening on the contact will sometimes suffice until a new rotor can be installed.

The contacts inside of the cap are also prone to corrosion and must be cleaned or the cap replaced as needed. Often corrosion can be scrapped off until a new cap can be installed.

The round shiny barrel like unit is the condenser. Think of it as absorbing and giving up electricity as the points open and close. This task allows the opening and closing without a spark being thrown which burns material from the points. Telephone switchboards often use gold plated contacts to help with this problem. It is said to always replace the condenser when you replace the points. Condensers are sized to each application so don't interchange with another. Personally I will sometimes NOT replace the condenser if the old points were pretty good indicating the condenser was sized properly and in good condition. Burned points indicates a condenser that isn't quite right for the points. You simply use a new one, not try to buy one of varying microfarads.

If you have a good spark coming from the coil wire to ground when you open and close the points you should have fire to start the engine.


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## rambler (Jan 20, 2004)

I think we should point out the _exact_ distance between those 2 contact circles on the points is very critical to the thousanth of an inch. One needs a feeler gauge to set them properly. This is very important.

--->Paul


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## agmantoo (May 23, 2003)

Here is a schematic and a thorough explanation
http://users.mrbean.net.au/~rover/ketterin.htm


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## .netDude (Nov 26, 2004)

rambler said:


> I think we should point out the _exact_ distance between those 2 contact circles on the points is very critical to the thousanth of an inch. One needs a feeler gauge to set them properly. This is very important.
> 
> --->Paul


So I should find a feeler gauge of .025, insert it between the points, and tighten them down? Is that how I'd make sure they are the right distance apart?


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## .netDude (Nov 26, 2004)

agmantoo said:


> Here is a schematic and a thorough explanation
> http://users.mrbean.net.au/~rover/ketterin.htm


Good article, thanks.


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## agmantoo (May 23, 2003)

The small lobes that open the points need to be rotated by turning the engine until one of the lobes has the small phenolic block on the peak of the lobe. This is when the points are open and when they should be set. The setting is to where you move the feeler gauge through the opening and parallel to the face of the point contact themselves. It should be a slip fit. After you get the points set, grasp the end of the shaft where the rotator button fits and move the shaft about with your fingers. The clearance should not change. Sometimes the bushing in the distributor will wear to where the cam lobes are not held constant as the shaft rotates. some minor slop is permissible. Once you get the points set, rotate the engine to where the phenolic block that rides the cam is off the lobes and observe that the points are now closed. This is essential just like having the clearance is mandatory. Remember, I stated above that you can use a coil off an old car. It does not matter if the coil is 6 or 12 volts. If your tractor has the 6 volt battery in correctly the + on the battery will be ground. If your coil is the original the primary will have - on the primary side of the coil. If you use a coil from a 12 volt, more modern vehicle, the wire from the original coil that goes to the - on the original will go to the + on the modern coil. The polarities were reversed from the mid 50's or so back on Ford products.


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