Troubleshooting help.

[Fnord235]

I'm at a loss with my 8N.
Any help would be appreciated. Full story bellow, but the summary is that it is not firing on the second cylinder.

I've checked the timing, rebuilt the carb, replaced the manifold gasket and inspected the manifold, have plenty of fire from the plug, and the plug is coming out wet after running it, and tested compression at 110 psi.

So, have fuel, fire, and compression...

I'm pretty sure its something I've done wrong. I've been working on it off and on for over a year now. It ran good several years ago then parked it due to the rear rim rotting out.

Starting last fall;
I replaced the rear tires.
Rebuilt the Carburetor.
Rebuilt the distributor.
Checked the timing.
Sprayed pb blaster into cylinder.
Poured Marvel mystery oil into the cylinder.
Replaced the manifold gasket and inspected the manifold.
Checked compression, 110 wet and 110 after running a few hours and then sitting for a couple days, dry.

Thanks for any suggestions.
Jeremy

 

[Tim PloughNman Daley]

Jeremy-
Is your 8N with a front mount distributor or angle mount; is it 6V/POS GRN or 12V/NEG GRN; or with EI? Either way is it wired correctly, firing order at 1, 2, 4, 3; and
timing set correctly? If all passes, it could be an internal engine issue. 99.8% of all assumed mechanical issues are actually electrical issues and vice versa. 110 PSI
compression is fine. If you do not already own a set, invest in the 8N ESSENTIAL MANUALS and digest religiously.

FORD 8N TRACTOR ESSENTIAL OWNER/OPERATOR/PARTS/SERVICE MANUALS:

Tim *PloughNman* Daley(MI)

 

[jon corbett]

bad contact in distributor cap or bad plug wire.might look like plenty of fire but its weak and compression (blowing it out)

 

[showcrop]

Please described the procedure used for timing.

 

[Fnord235]

Thanks for reply.
Angle mount distributor.
12 V converted. Neg GRN
Yes firing order 1-2-4-3.

I believe the timing is set correctly. More on that in a later reply, since someone asked about that specifically.

At this point I'm out of assumptions.

I've got the IT manual and the parts manual around somewhere.

Thanks, Tim

(quoted from post at 05:48:24 11/20/19) Jeremy-
Is your 8N with a front mount distributor or angle mount; is it 6V/POS GRN or 12V/NEG GRN; or with EI? Either way is it wired correctly, firing order at 1, 2, 4, 3; and
timing set correctly? If all passes, it could be an internal engine issue. 99.8% of all assumed mechanical issues are actually electrical issues and vice versa. 110 PSI
compression is fine. If you do not already own a set, invest in the 8N ESSENTIAL MANUALS and digest religiously.

FORD 8N TRACTOR ESSENTIAL OWNER/OPERATOR/PARTS/SERVICE MANUALS:
<center><img src="https://i.imgur.com/qI9P22kh.jpg"></center>

Tim *PloughNman* Daley(MI)

 

[Fnord235]

New plug wires and plugs.
Also tried cap off of another 8n that ran before sitting with the same results.
Have not checked for proper fire but looked like plenty of fire and the spark will jump at least an 1/8th inch.

 

[Fnord235]

New plug wires and plugs.
Also tried cap off of another 8n that ran before sitting with the same results.
Have not checked for proper fire but looked like plenty of fire and the spark will jump at least an 1/8th inch.

 

[8NChris]

(quoted from post at 06:03:58 11/20/19) New plug wires and plugs.
Also tried cap off of another 8n that ran before sitting with the same results.
Have not checked for proper fire but looked like plenty of fire and the spark will jump at least an 1/8th inch.

hen I have a missfire come in with good quick test results I will move injector, plug and coil to different cylinders and see if problem moved. The same principal with any engine. Are the wires long enough to swap wires with 2 and 3? If that is all good you could have a weak coil and #2 plug and wire are at the max end of the resistance tollorance.

Since the Flathead valves are upside down there is a good chance you have a broken valve spring that is not snapping the valve shut while running. Gravity closing them while testing static. I have seen a few come in that the valves were simply sticking or moving too slow to close at running rpms. You can check this with a running compression test. To do a running compression test pull your Schrader valve and run the gauge while the tractor is idling. On a healthy cylinder your engine should be in the 20-25 psi range.

 

[Bruce (VA)]

" the plug is coming out wet after running it"

That's your first problem. You flooded it. Your plugs are fouled & it will be it next to impossible to start. You don't need to toss them; heat the tips for a few seconds w/ a propane torch to burn off the invisible spark-robbing deposits from today's additive filled gasoline........or wash them in brake cleaner.

" So, have fuel, fire, and compression..."

Your compression is fine. But, tell us more about fuel and spark.



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?

Once you narrow the problem to spark or fuel, post back and tell us what you found (and how you found it) and you will get plenty of help to get your tractor running.



* 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

 

[8NChris]

* 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

ruce, on a 12 volt system a yellow spark is a sign of a weak coil. I take it on a 6 or 8 volt system that is acceptable? If so it makes sense.
Thanks

 

[Jim L WA]

I like 8NChris's method of trouble shooting and his suggestion about sticking valves. It's not flooded. If you flooded it why would the other 3 cylinders be working. That spark plug is wet because that cylinder isn't working.

 

[Bruce (VA)]

" Bruce, on a 12 volt system a yellow spark is a sign of a weak coil."

A weak spark could have many causes: a weak battery, bad resistor, bad wires, incorrect points gap...?.etc, etc.

Why would you assume there is only ONE cause?
75 Tips

 

[8NChris]

(quoted from post at 15:51:46 11/20/19) " Bruce, on a 12 volt system a yellow spark is a sign of a weak coil."

A weak spark could have many causes: a weak battery, bad resistor, bad wires, incorrect points gap...?.etc, etc.

Why would you assume there is only ONE cause?
75 Tips

hy would you assume I thought it was?

 

[Bruce (VA)]

Because you clearly said " on a 12 volt system a yellow spark is a sign of a weak coil."
Untitled URL Link

 

[a32vickyhotrod]

.

Sounds like exhaust valve problem. Also, in situations like this don't trust the new ignition parts, swap or switch them out for known good ones. Good luck and let us know what you end up finding wrong.

 

[Elmo]

(quoted from post at 10:48:24 11/20/19) Jeremy-
Is your 8N with a front mount distributor or angle mount; is it 6V/POS GRN or 12V/NEG GRN; or with EI? Either way is it wired correctly, firing order at 1, 2, 4, 3; and
timing set correctly? If all passes, it could be an internal engine issue. 99.8% of all assumed mechanical issues are actually electrical issues and vice versa. 110 PSI
compression is fine. If you do not already own a set, invest in the 8N ESSENTIAL MANUALS and digest religiously.

FORD 8N TRACTOR ESSENTIAL OWNER/OPERATOR/PARTS/SERVICE MANUALS:
<center><img src="https://i.imgur.com/qI9P22kh.jpg"></center>

When I was growing up and my dad was teaching me to diagnostics on engines he would say "90% of carburetor problems are in the ignition system".
Elmo

Tim *PloughNman* Daley(MI)

 

[soaked]

Just a guess--- wires in dizzy loaded
backwards.Confirm 1-2-4-3 wires are
installed counter clockwise. If wired
backwards, and #1 is in the correct
spot, then so is #4. Swap #2 into the #3
spot. Hope it works--

John

 

[Fnord235]

Good call soaked.
That was the problem, figured it out before I read your post.
Somewhere during the other problems with the carb and ignition system I convinced myself that the distributor ran clockwise.

I never pulled the back wire while it was running so I thought it was running on 3 cylinders rather than the actual 2 it was running on. In my defense it ran damn good for only 2 cylinders.

Been running well and seen much usage since I sorted this out.

Since then I've only had to replace the fan belt, and the exhaust assembly.

Thanks for all the help everyone and sorry for the long delay in this reply.

Just got to clearing out some old e-mails etc. and realized I stalled in posting a reply here due to embarrassment until I totally forgot to reply at all.

Next project will either be the 6v 8N with a short that was cannabalized to get this one running, or carb rebuilds on the Farmal Super C or M. Any suggestions now that my low skill level is known.

-Jeremy