8n hard initial start poorly running

183beast

New User
I have a 1947 8n that is an extremely hard start.
After the 1st start it normally fires right up. Once it?s
running it doesn?t run very well. Seems to hesitate
and stall but it will drive around.

It?s a 6v front mount distributor. I?ve replaced the
points with a blue streak set. I have a blue spark
from the plug but i wouldn?t call it super strong.
Heard that these are like that though.

I?ve checked the carb screens and have good fuel
flow. Removed the bowl on the carb and it?s
suprisingly clean! I?ve looked through the 75 tips
already as well.

My compression was 85,85,85,90

What would be the next step to get this thing
running correctly? I feel like this thing is extremely
simply, but I must be missing something. Any and
all help is appreciated!
 
What does the choke PLATE look like? Little Spring is not broken and the Little Flapper is intact?

Have you removed the carb air tube and choked it by hand?

DO you keep the clutch down when cold starting? The starter doesn't need to turn the gears, too...
 
" Heard that these are like that though."

Nope.

If you don't get a spark to jump 1/4" in open air, you have a weak 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
 
Try cranking it over in complete
darkness , If there are sparks
tracing around the coil tower or
distributor , then they could be cracked
a bad rotor will arc thru the center and
short out on distributor shaft .
 
183beast,Check your spark 1/4" also check your firing order you could have crossed up two wired in your attempts.It will run on two cylinders but not good as you say it does,also check for stiff/cracked plug wires.
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I would venture to say its your carb. I had a 47 that was the same way. fooled with it checking everything then just bought a new carb off ebay. fixed everything. those carbs has gotten so cheap its almost cheaper to buy a carb than a kit especially if your like me that I aint very good on rebuilding carbs. I have an naa now. same problems, new carb now. starts great and still 6 volt system.
 

Well, I filled 16oz bottle in under 2 minutes.

Used and old spark plug and it will jump 1/4 gap when it does spark, but it?s not hitting all the time. Seems to be missing in between.
 

one easy check for the cause of intermittent spark is to run a jumper wire from the hot post of the battery (positive ground? if so, run the wire from the battery negative) to the stud on top of the coil. if the tractor starts easily and runs well, you've eliminated the coil and distributor as culprits. remember, you'll have to pull the jumper wire back off before u shut the tractor down, or it will ignore the key being turned off.
 
Before you do anything else, confirm the firing order, 1-2-4-3, ccw and that the wires are firmly seated in the cap and on the plugs.

When is the last time you replaced the plugs, wires, condenser, points, cap & rotor and set the timing?

Ever checked the bushings or advance weights?
75 Tips
 

Firing order is correct, replaced the plugs and gapped them autolite 216s. Point were replaced with blue streak. The cap/rotor and wires were not replaced but they do not seem bad.

jumper wire from the coil to the battery produces a much stronger spark and much easier to start.... so I gues I need to figure out what?s bad in there.

But it still runs poorly. The governor is bouncing erratically, but seems to smooth out if I just hold the rod In place. Any thoughts?
 

[i:3377d245a5]"jumper wire from the coil to the battery produces a much stronger spark and much easier to start.... so I gues I need to figure out what?s bad in there."[/i:3377d245a5]

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