8n won't start

So I just finished converting my 8n to 12v. I put the hood/gas tank on, hooked up the lines and all that. It turns over great so it's a successful conversion but she won't fire. It won't even try to fire. Checked the spark and it's good. It's got air coming through the carb but the gas line by the fuel bowl was leaking at first. So I tighten up the line some more and problem solved. Then the fuel bowl started leaking. Every thing on the bowl assembly is tight. The only thing I can think of that I didn't do is unhooking the gas line by the carb and bleeding the line out. Any insight is appreciated

Take the plug out of the bottom of the carb and make sure you have good fuel flow for at least 2 minutes. Second, will your spark jump a 1/4" gap? Third, did you stick with
positive ground or go to negative ground? Did you use a true 12v coil or are you using a 6v coil with a resistor? What all did you do to convert the machine to 12v?

Give us some answers to these questions and we'll get you pointed in the right direction.

Front or side distributor?

Don?t guess at the cause of the problem; guessing can get expensive. And leave you breathless chasing every guess.......it could be this, it could be that......just troubleshoot the problem and leave the guess work for buying Lottery tickets.

Check for spark and fuel. (see tip # 13)

You need to answer 2 questions before you do anything else:

With the bolt in the carb bowl removed and the gas on, will the fuel flow fill a pint jar in less than 2 minutes?

Next, get out your adjustable gap spark checker * , open the gap to 1/4", hook it up, turn the key on and crank the engine. Does the spark jump 1/4"? Post back with the answers.

And do not buy a new part for the tractor until you can answer this question: how do I know the part on the tractor is defective?



* Don't own an adjustable gap spark checker? Buy one! Not a test light! Until then, take an old plug, open the gap 1/4" ground it to the head & look for spark. It?s not the color of the spark that counts; it?s the distance it jumps. https://www.amazon.com/AMPRO-T71240-Energy-Ignition-Tester/dp/B00A8FO87S/ref=sr_1_fkmr1_4?ie=UTF8&qid=1513273147&sr=8-4-fkmr1&keywords=ampro+spark+checker
75 Tips

I ordered a whole 12v kit and used a 12v coil and used positive ground and it has good spark. I'll check the gas going to carb tomorrow

(reply to post at 19:44:16 02/21/18)

Click to expand...

Front distributor. Tractor always started fine before. Previous owner put new points in. I've had it for about 6 months

Unless you see the spark jump 1/4" in open air, you do not know if it has a good spark.
75 Tips

I ordered a whole 12v kit and used a 12v coil and used positive ground and it has good spark.

Click to expand...

Not relative to your problem but most alternators require a negative ground.

As BB & Bruce indicated, you likely have a fuel delivery problem.

One other question - As this is a FM distributor, did you retain the OEM ballast resistor? Remember, you don't need a 12V converting resistor with a 12V front mount coil.

Your cue is that the fuel bowl is leaking. Gasoline should never be high enough to leak when the tractor is sitting still so look for a leaking float valve. Getting too much gasoline is as bad as not enough when starting.

Regarding your sediment bowl leak............. turn the knob off fully, remove the bowl & carefully check the groove in the top of the assembly for dirt/crud/old gasket material. Most leaks on a new gasket are caused by:

1. An incorrectly seated gasket.

2. An incorrectly seated screen.

3. A screen just slightly too big . (get out the scissors)

4. Using gasket sealer

5. Incorrect assembly of the screen/gasket

Don't forget to check the bowl rim for chips; if it's chipped, you will never get it to stop leaking. Clean or replace the screen. You can get both the cork gasket & the screen from TSC; p/n 0237144. A cork gasket will work if you soak it first in gas, but I like rubber. Check out tip # 10 at the link below for the correct NAPA part number. However, the newer ones aren't as thick as the old ones and the price is now $4 each. I've got the new ones to work, but it takes a few tries. And, at $4 for a thinner gasket, I'm not planning on using the NAPA gaskets anymore.

Look at the bowl; see the groove in the lip? That's for the screen. Put it in there & make sure it does not extend over the lip. If it does, trim it, but not too much or it will fall in the bowl. See the square hole in the screen? That because it needs it fit around the square fuel port in the top of the bowl when you assemble it. The gasket goes on next, on the lip of the bowl. Once you get it assembled on the tractor, hand tighten the thumb screw. (if it makes you feel better, turn it about 1/8 turn w/ channel locks; no more, or you will distort the bail) Turn the gas on & look at the bowl. If it starts to fill the bowl, turn the gas off & start over; it has a leak.

You will know it's sealed when gas does not flow into the bowl w/ the engine off. It won't fill with the bowl securely on because the float has closed the needle valve in the carb and there is nowhere for the air in the bowl to escape. (assuming the carb bowl is full) When the engine is started the needle valve will open and the trapped air will escape through the carb vent. If you loosen the bowl, it will fill.....and leak.

Do not open the valve more than 2 or 3 turns. All the way open gets you the 1 gallon reserve & that port is usually clogged.

Tightening the knob may fix the leak there. If not, go to the hardware store, plumbing counter & get some graphite packing thread (not teflon) Pack it like a faucet.

All of the above assumes you have an OEM sediment bowl. If not, I'd get one because a lot of the off-shore replacements never work right & the gaskets are odd-sized.

I've got quite a collection of junk sediment bowls around here that were on the N's when I bought them. Nearly every type of leak on the OEM Ford sediment bowl can be repaired. My guess is the previous owners didn't know how or , as is way to often the case with these old tractors., "fixed it" by buying a piece of off-shore junk. It all depends on your supplier; I've never got a bad one from nnalert's. The stems can be replaced. (on an oem style bowl) . But, cross-threading a steel fuel fitting into an aluminum sediment bowl is fatal. Always, always finger-tighten the lines at both the carb and sediment bowl. And then use a flare or line wrench to tighten the fittings. ( see tip # 56). Bottom line: buy parts from reputable dealers & pay attention to what you are doing.
75 Tips

(quoted from post at 22:48:35 02/21/18)

I ordered a whole 12v kit and used a 12v coil and used positive ground and it has good spark. I'll check the gas going to carb tomorrow

Click to expand...

2v Positive ground is a red flag, but not stop it from starting, just ruin the alternator.

(quoted from post at 21:03:17 02/22/18)

(quoted from post at 22:48:35 02/21/18)

I ordered a whole 12v kit and used a 12v coil and used positive ground and it has good spark. I'll check the gas going to carb tomorrow

Click to expand...

2v Positive ground is a red flag, but not stop it from starting, just ruin the alternator.

Click to expand...

Never mind it is negative ground. Just looked at it