# Old 8n won't start



## lwooten1201 (4 mo ago)

Looking for some help with an old 8n tractor that was my great grandpa's.....started working on it and couldn't get it to run so dropped it off with a guy to fix it and he can't figure out what is wrong with it. Originally had not point connection, he fixed that. Didn't have enough compression, had a lot of carbon build up so he cleaned that out.....compression is restored. Cleaned the fuel tank out, replaced the coil selunoid and the spark plugs. Can't figure out what is wrong with it, guy says he still cant get it to crank.....any ideas? Thanks


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## Ford5610II (Jun 11, 2020)

First, welcome.
Now to your questions:
1. Do you have spark? Take a plug wire off pull a spark plug and crank it while holding the plug and wire with a pair of insulated pliers against the block. One end of the spark plug is hooked to the plug wire, the other end is against the block, and you should see a blue spark in the plug gap.
2. Do you have fuel getting to and through the carb?
3. Is it timed correctly? 
4. Caution: This tractor was originally 6-volt, and positive ground. Don't hook up a 12V battery.
5. Strongly suggest getting an operators manual, and a parts manual for your tractor.
6. There is a lot of information on these tractors, both in this and other forums, articles, and on videos/you tube, etc. do a search for the type of tractor and whatever you're interested in. For example, there are great videos on rebuilding the carb, or the hydraulic pump.

Best of luck, we are interested in seeing pictures of your project.


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## thedukes (Jan 9, 2022)

The beauty is there is no computer.

Follow the above steps.^^^^^^^^ Ford xxx posted
1 spark
2 fuel...there is a drain bolt on bottom of carb.
3 6v pos ground.........they will run the other way but that confuses generator if its still good.

figure out 1-3 and report


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## lwooten1201 (4 mo ago)

The only thing that I'm not sure of is if it is getting fuel....it does have spark. I'm wondering if there is a issue with the carburetor or the fuel line going to the carb..... the tractor attempts to start but just can't quite turn over.


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## Ford5610II (Jun 11, 2020)

Sounds like your battery needs a boost.


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## lwooten1201 (4 mo ago)

Brand new battery


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## lwooten1201 (4 mo ago)

We pulled the plug on the carb to see if it had fuel to it and it was a slight drip.....not very knowledgeable about this stuff so I'm not sure what it is supposed to look like


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## HarveyW (Sep 15, 2014)

You should be able to fill a pint jar in 2-3 minutes from the drain plug on the carburetor bowl.


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## lwooten1201 (4 mo ago)

HarveyW said:


> You should be able to fill a pint jar in 2-3 minutes from the drain plug on the carburetor bowl.


Ok, it definitely didn't have enough of a drip to accomplish that....so that is very insightful


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## thedukes (Jan 9, 2022)

Does the fuel tank still have the Glass bowl under it with the round knob??

1 turn out is "ON"

to get to the fuel at bottom of tank...Open knob all the way ...Several turns.

Clean the knob...directions are stamped on it.

There is a Brass elbow on carb where Gas enters.

On the back of that elbow is a Screen.

Be very carefull if you mess with this as you can wreck that elbow super easy and fuel line Will NOT re connect.

Pull glass bowl from under tank and clean.
While its off ...open valve ...With a catch can under that area and be sure there is gas flow.

Fire ext. handy would be a great idea.

Should be a metal fuel line from Glass bowl ...to Carb.
No rubber...No fuel filter...all down hill..Its gravity fed.


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## fuddy1952 (Mar 6, 2021)

If you're getting spark, choke&throttle open spray a little starting fluid in & try.

Sent from my SM-S205DL using Tapatalk


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## thedukes (Jan 9, 2022)

Check and clean the oil bath air cleaner.

This is an hour long project to do it right.

or just dis connect the Air cleaner inlet tube At Carb to get it started.


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## lwooten1201 (4 mo ago)

thedukes said:


> Does the fuel tank still have the Glass bowl under it with the round knob??
> 
> 1 turn out is "ON"
> 
> ...


I replaced the bowl because the original got stuck and would not turn. Put the new one on and it filled with fuel but as I said earlier there was only the slightest of drips coming from the varb....so I'm wondering if there is an issue with the brass fuel line or the carb


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## lwooten1201 (4 mo ago)

thedukes said:


> Check and clean the oil bath air cleaner.
> 
> This is an hour long project to do it right.
> 
> or just dis connect the Air cleaner inlet tube At Carb to get it started.


hcarbhave also cleaned the oil bath air filter and have also disconnected the air inlet


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## thedukes (Jan 9, 2022)

Next step is that screen in the elbow to carb.

There is a screen in the Glass bowl as you will see in video and another internal on the fitting in to tank. Follow the flow.......









Watch all this Gals Video's........you will learn a lot.
Her folks own a tractor parts store as well....I've been pleased.






here is part about elbow /screen

Watch Again near the end of assembly of carb for proper wrench placement.
I wrecked mine cause I didn't listen...don't do what I did.


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## lwooten1201 (4 mo ago)

thedukes said:


> Next step is that screen in the elbow to carb.
> View attachment 82337
> 
> 
> ...


Ok I'll look into all of that, thanks a ton


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## Groo (Jan 17, 2020)

hate to say something that might come off as accusatory, but is it possible Grandpa converted or partially converted it to 12v?


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## thedukes (Jan 9, 2022)

Groo said:


> hate to say something that might come off as accusatory, but is it possible Grandpa converted or partially converted it to 12v?


If converted to 12v...it probly has a chevy alternater.

Pics of this tractor may help...mostly cause we like tractor pics but a Lot of info can be had from a few well placed pictures.


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## LouNY (Dec 15, 2016)

Posts #1 and #3 have the engine not turning over, not cranking. That would be starter, battery or something dragging the engine down so as to not allow it to crank over.
IF it's cranking over the above information will help,
IF it's NOT cranking over find out why. Will it turn over with a wrench on the front pulley, have you tried tow starting it?
Try a 12 volt battery to start it, if the starter is in good shape it will spin over good, and for a short run it will not hurt the coil,
just do not turn on any lighting.


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## VFord8N (Aug 18, 2013)

One very simple thing I found is that a gas tank must have about 1/4 tank to start. Ensure there is sufficient gas. Fresh of course and perferably super. If everything fails, you may need to rewire as those wires are quite old and provide much too much resistance to electrical flows to the spark plugs.


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## pogobill (Jan 31, 2012)

VFord8N said:


> One very simple thing I found is that a gas tank must have about 1/4 tank to start. Ensure there is sufficient gas. Fresh of course and perferably super. If everything fails, you may need to rewire as those wires are quite old and provide much too much resistance to electrical flows to the spark plugs.


I've had a "No Start" as few times and that's the first thing I check now. Saves a lot of time trying to trouble shoot a low fuel situation!


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## thedukes (Jan 9, 2022)

Ford 8N Tractor Fuel System







www.myfordtractors.com





Good info site for the 8n's and the 2 & 9.


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## Mudwallower (Dec 8, 2020)

"guy says he still cant get it to crank." Will not crank or fire?? Crank means the engine will not turn over by hand or starter. Fire means one or more of the cylinders will not ignite the air/fuel mixture.


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## jerrymcgeorge67 (5 mo ago)

lwooten1201 said:


> Looking for some help with an old 8n tractor that was my great grandpa's.....started working on it and couldn't get it to run so dropped it off with a guy to fix it and he can't figure out what is wrong with it. Originally had not point connection, he fixed that. Didn't have enough compression, had a lot of carbon build up so he cleaned that out.....compression is restored. Cleaned the fuel tank out, replaced the coil selunoid and the spark plugs. Can't figure out what is wrong with it, guy says he still cant get it to crank.....any ideas? Thanks


What do you mean can't get it to crank. Will the starter crank?


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## John Liebermann (Sep 17, 2018)

Mudwallower said:


> "guy says he still cant get it to crank." Will not crank or fire?? Crank means the engine will not turn over by hand or starter. Fire means one or more of the cylinders will not ignite the air/fuel mixture.


I am so glad you brought this to attention. The word "crank" is misused too often and causes problems in understanding the real problem.


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## Busted Tractor (May 22, 2018)

I often see posts recommending premium gasoline in old farm tractors and wonder why others recommend it. Most farm tractors have a compression of 5 or 6 to 1. Therefore they don't need it. Consider one more thing premium gasoline is higher octane. Octane (87 vs 91) is the resistance to ignition, so you may be making it harder to start be using premium. Premium depending on the brand may contain more detergents, but does cost more. I have often heard people state than premium does not contain ethanol, sorry it has just as much as regular. If using oxygenated fuels (fuels containing ethanol) the shelf life is often recommended to be 30 days, I know the companies that make stabilizers often say it extends the life of the fuel for long periods of time, but I personally don't believe the hype. The best thing if you desire to store gasoline is store it in a dry, cool dark place where the temperature does not vary. 
To avoid ethanol issues especially for tractors that aren't used much is to use nonethanol gasoline. Yes I know it costs more than premium, but it has a longer storage life and will not phase separate, or take water out of the air.


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## pblanton (Mar 17, 2015)

Busted Tractor said:


> I often see posts recommending premium gasoline in old farm tractors and wonder why others recommend it. ...


High-octane gasoline is often required for high-output engines that have higher compression ratios than regular engines. If you put regular gasoline in high compression engines then the gasoline will tend to ignite before the spark which causes the engine to knock and rattle. This causes excess heat build up and is hard on the cylinder walls, pistons, and connecting rods. High-octane gasoline doesn't provide more power, but it allows high-power /high-compression engines to run efficiently. It's the properly tuned, high compression engine that delivers more power. You can think of octane as somewhat numbing the gasoline to compression-induced ignition.

People misunderstand what exactly Octane does. Most people think it adds more power to the gasoline, which it does not. This spills over into the culture as things like a "high octane cup of coffee" or a movie that is a "high octane thriller". Does that mean that the coffee or the movie can be compressed much harder before it burns, therefore preventing pre-ignition? One thing that would make sense is "hi octane boner pills"... think about it. 

The fact that high-octane gasoline is more expensive makes people think it's better / more powerful; but you're just falling prey to the petroleum company's marketing if you think that. High-octane gasoline isn't particularly more expensive to produce aside from the expense of the overhead of producing, transporting, marketing and delivering multiple lines of fuel. What would make sense is for the petroleum companies to configure their pumps to inject a little bit of octane additive to regular fuel when it is dispensed from the "high-octane" nozzle and charge a small premium-per-gallon for the "hassle" of having to do that. 

Unfortunately petroleum companies love it that people don't understand the purpose of octane and think it makes the gasoline somehow "better". In fact they love it so much that they spend hundreds of millions of dollars on marketing that reinforces the misconception so that they can charge so much more for high-octane "premium" gas. The name "premium" is a marketing term in itself. Don't fall prey to marketing. Much of what you believe about the world is a lie. That's the purpose of marketing; to make you believe lies so that you spend money that you don't need to be spending, for products that you don't need.

Now back to the original question, the answer is NO. Old gasoline powered tractors are NOT high-compression engines and do NOT need high-octane, premium gasoline. You can put it in if you want, but it's a waste of money; unless it makes you feel good. I guess there's value in feeling good.


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## 2billt (Aug 7, 2011)

John Liebermann said:


> I am so glad you brought this to attention. The word "crank" is misused too often and causes problems in understanding the real problem.


I absolutely agree with you....

Troubleshooting Preschool 101
_* #1....No Crank, No Start
#2...Cranks, No start*_


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## LouNY (Dec 15, 2016)

pblanton said:


> High-octane gasoline is often required for high-output engines that have higher compression ratios than regular engines. If you put regular gasoline in high compression engines then the gasoline will tend to ignite before the spark which causes the engine to knock and rattle. This causes excess heat build up and is hard on the cylinder walls, pistons, and connecting rods. High-octane gasoline doesn't provide more power, but it allows high-power /high-compression engines to run efficiently. It's the properly tuned, high compression engine that delivers more power. You can think of octane as somewhat numbing the gasoline to compression-induced ignition.
> 
> People misunderstand what exactly Octane does. Most people think it adds more power to the gasoline, which it does not. This spills over into the culture as things like a "high octane cup of coffee" or a movie that is a "high octane thriller". Does that mean that the coffee or the movie can be compressed much harder before it burns, therefore preventing pre-ignition? One thing that would make sense is "hi octane boner pills"... think about it.
> 
> ...



I'll have to disagree with several statements here.
Pre ignition has nothing to do with the grade of fuel.
Pre ignition occurs when hot carbon is still glowing when gasoline and air combine in the cylinder.
When you here spark knock or minor preignition it is from timing to far advanced for the fuel being used.
The difference in octane of fuel is the burn rate of fuel, the higher the octane the slower the burn rate.
A high compression engine with high test gas has a slow burn which is extending the power cycle of the engine
from the fuel air mixture expanding after ignition,.
Ignition timeing has a major effect on spark knock and fuel requirements.
In some locations premium gas does not have any alcohol in it so it is more stable and less likely to degrade while sitting in the tractors tank.
Most older engines that don't get a lot of use and still have soft valve seats will beniftit from an additive to lubricate and cushion the valves..


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## VFord8N (Aug 18, 2013)

Old engines (of all kinds) have rubber seals and any ethanol in other than premium fuel will slowly destroy them. The new stuff is built to accept ethanol. Not so in days gone by. Premium non ethanol is the preferred fuel (according to my very knowledgeable car mechanic). Keep that in mind.


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## bentrim (Nov 1, 2014)

LouNY said:


> I'll have to disagree with several statements here.
> Pre ignition has nothing to do with the grade of fuel.
> Pre ignition occurs when hot carbon is still glowing when gasoline and air combine in the cylinder.
> When you here spark knock or minor preignition it is from timing to far advanced for the fuel being used.
> ...








Gasoline explained - octane in depth - U.S. Energy Information Administration (EIA)


An introduction to gasoline octane, why octane is important, and how it is measured.




www.eia.gov






https://en.wikipedia.org/wiki/Octane_rating



Please review the links for a better understanding of octane and preignition.
As an old hot rodder and having modified engines. I have found that increasing compression, adding a high performance cam, replacing a 2 bbl carburetor with a 4 bbl carburetor increased the chances of preignition occurring. Anything that increased the volumetric efficiency of an engine increases the heat of compression which increases the chanes of preignition. Most high performance car be fore computers required premium fuels due to the higher compression, most were machined combustion chambers without sharp edges and certainly had little or no carbon to preignite the fuel mixture. Yes timing could affect preignition also. I used to advance the timing until I heard it ping then backed off the timing until the pinging stopped.
As for your statement of additive for valve lubrication I agree.


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## beauregaardhooligan (Oct 14, 2017)

Not that this is pertinent to the original post, but ping absolutely can be affected by the octane of the fuel, all other things being the same. 
I used to set the timing on my old /6 by listening for the ping. I would advance the timing till it just started to ping under WOT, then set it back a touch. If I set it to run on premium and then put regular it would start to ping right away. If I had it set for regular and then put premium, it would not ping and I could advance the timing quite a bit. It did give a little bit more pep and throttle response but not enough to justify the cost.


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## LouNY (Dec 15, 2016)

bentrim said:


> Gasoline explained - octane in depth - U.S. Energy Information Administration (EIA)
> 
> 
> An introduction to gasoline octane, why octane is important, and how it is measured.
> ...


Those are not the best articles I have ever seen of fuels.
Certainly adding compression or volumetric efficiencies will add to the possibility of spark knock.
The reason for premium fuel in higher compression engines was to slow the burn rate down so as not to get spark knock and to allow additional timing.
Also it produces a longer smoother power stroke in the engine.
I've also hot rodded many engines in my younger days, I still do to a limited extent. Such as a small tractor engine that likes sunoco race fuel because of the compression and timing that we are running in it. It's a little 226 cu. in. 4 cylinder, originaly it had a 6.45 to 1 compression ratio now we are close to 10 to 1. Originaly 45 HP now closer to 75-80 HP.


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## Busted Tractor (May 22, 2018)

*Here’s where the “faster burn” misconception comes from. It’s a semantics issue.*
You inject X amount of 87-octane fuel into the combustion chamber, compress it, and ignite it, creating multiple flame fronts. With multiple flame fronts occurring at the same time, _*of course it’s going to burn UP all the fuel faster.*_ But that doesn’t mean the fuel itself burns faster than 93-octane. _*If you were to take the same about of 93-octane fuel and cause the exact same number of multiple flame fronts, it would burn up at exactly the same rate as the 87-octane fuel.

from the link Does regular gas burn faster than premium gas? — Ricks Free Auto Repair Advice Ricks Free Auto Repair Advice | Automotive Repair Tips and How-To *_


Tech-BTU Content of Gasoline.pdf (rockettbrand.com) 

I note there a articles that state regular burns faster than premium but speed of burn according to the last link is more concerned with BTU content of the gasoline. If higher octane fuel burned slower there would be an increase in torque output due to the longer "burn" time. This is where a diesel gets its torque output, the fuel burns slower giving a longer power stroke.



Motor gasoline1 gallon = 120,238 Btu*Diesel fuel**1 gallon = 137,381 Btu *
Have a wonderful day


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## TractorRookie (Dec 6, 2021)

Soooooo did the OP ever get this thing running ???


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## pogobill (Jan 31, 2012)

Seems he's abandoned ship!


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## wolfang (2 mo ago)

If you convert to 12 volts like I did on the 1939, you will need a resistor to lower the voltage going to the old style 6-volt front mounted distributor and a toggle switch cutoff when the tractor is not running as not to burn up the points and you can see this on the meter that shows if the battery is being charged by turning on the toggle switch with the engine off will show a discharge on the meter and most people use a chevy alternator with a built in regulator. I heard there is complete kits to upgrade these old tractors electrically. Use starting fluid to see if it will turn over and try to run. if it does then the problem is fuel related. You better off to buy an aftermarket carb because they are upgraded from the old dinosaur style even though they will look almost identical. You may go through several sparkplug changes before it hits a lick. The plugs will foul out pretty easy if it is getting fuel and doesn't fire soon. Like I have said before these old tractors require a lot of mechanical work. Buy a big toolbox rite? k


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## Joe.S.AK (Nov 26, 2020)

*"You better off to buy an aftermarket carb because they are upgraded from the old dinosaur style even though they will look almost identical. "*

This is a curious thing to say. From my personal experience, as well as that of MANY others here and elsewhere, the Chinese after market, shiny, new looking carbs simply were cloned *very* poorly. If you still have the old carb my advice would be to METICULOUSLY tear down the old carb, clean it *thoroughly, *reassemble, and then see if that works. If not, get a good full rebuild kit and very carefully rebuild and adjust the old carb to run well.

If your carb rebuilding is a little rusty then Rachel might be able to help (Rachel Knows All) :






If you do decide to R&R the old carb then do yourself a big favor and carefully put that precious old one away in storage. Dollars to Donuts it's going to be needed, really needed, in the very near future. - Joe S -


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