NAA Ford Jubilee Misfires

CFW

New User
I have a 1953 Golden Jubilee that has always had a very slight missfire. sort of a puffing at the end of the tail pipe. She Uses no oil...No smoke. I replaced the distributor with a new one. New coil...new plug wires. Set the timing at 8 degrees BTDC. New Sediment fixture...New 12 volt resistor (my tractor is a 12 volt conversion) new ignition switch...It runs better at fast idle. I tried Seafoam...Tractor has plenty of power
 
" New coil...New 12 volt resistor"

Why are you using a resistor? Unless you have a 6v coil or bought the wrong coil, you don't need a resistor.

check the firing order, 1-2-4-3, CCW.

" Set the timing at 8 degrees BTDC."

That's static timing. What about dynamic timing? (with a light)

0 to 450 8 degrees
1200 17 1/2 to 19 1/2 degrees
2000 29 to 31 degrees

Does it "misfire" at all speeds or just at idle?

And finally......these old carbs will puff & snort if the mixture is off.

You can tell the difference between tat sound & a true misfire, right?

What happens if you pull the choke out a bit?
75 Tips
 
Your idea of a "puffing" sound might be different than
mine. My first thought was a leaking exhaust valve.
In
They make noise out the exhaust. They make more of a
"hissing" or "sucking" noise in my opinion than a
"puffing" noise.
 
How about the "hold a dollar bill or strip of paper bag trick" at the end of the exhaust..If it tries to suck it in, you have valve issues...Anybody done this?
 
CFW, welcome to the forums!
It is hard to tell exactly what you are hearing from here,
so puffing at idle may be a "normal" thing depending.

If the tractor runs fine above idle I would think your
firing order is probably correct. Firing order is 1243, but
unlike the rest of the N series the NAA distributor turns CW.

Can you post a video of it with sound so we can hear it?
I would also run a compression check just for peace of mind.
You state plenty of power, so that may be a stretch, but its free.

BTW, posting the same question on three or more YT forums
on the same day is generally considered a faux pas.
When it comes to N's, you'll get the fastest answers here.
 
Sorry about the multiple postings. I'm new to this...Just didn't mean to offend anyone. Thanks for everyone's advice. you all have been a great source of information.
 
plus one on the valves.

dunno why it is. (not you CFW, just generally)
I go thru a lot of tractors.
Even the ones that have had decent care and tune-ups,
that ol valve cover hasn't been off in years and years.
All I've had, with only 1 exception ( a [i:9f0a1447c8]very[/i:9f0a1447c8] well kept Deere M)
has needed a valve adjustment.
Buy a tractor, change oils, do the carb and ignition....and adjust the valves.
Solid lifter engines...it's normal maintenance.

You don't have to be a master mechanic (I'm not)....just try to think like one..'It's not right until [b:9f0a1447c8]I[/b:9f0a1447c8] do/check it.......'
 
(quoted from post at 15:42:26 07/05/15) How about the "hold a dollar bill or strip of paper bag trick" at the end of the exhaust..If it tries to suck it in, you have valve issues...Anybody done this?
 
Well...I should say that I started at 8 degrees BTDC...Then turned the distributor until she smoothed out... then just a bit of labor and locked her down. Then checked it with a light. I started with the rotor pointing to the #1 cylinder and showing 8 to ten degrees on the flywheel peep hole...Just to get her started. Firing order on the NAA Tractors is Clockwise (CW).


(quoted from post at 11:22:42 07/05/15) " New coil...New 12 volt resistor"

Why are you using a resistor? Unless you have a 6v coil or bought the wrong coil, you don't need a resistor.

check the firing order, 1-2-4-3, CCW.

" Set the timing at 8 degrees BTDC."

That's static timing. What about dynamic timing? (with a light)

0 to 450 8 degrees
1200 17 1/2 to 19 1/2 degrees
2000 29 to 31 degrees

Does it "misfire" at all speeds or just at idle?

And finally......these old carbs will puff & snort if the mixture is off.

You can tell the difference between tat sound & a true misfire, right?

What happens if you pull the choke out a bit?
75 Tips
 
Y'know, I've had a Jubilee for the past dozen years that under random circumstances will start "popping" from the exhaust about once or twice a second at mid-throttle. Over the years I've done everything
from compression checks to swapping carbs with another tractor to cleaning the valve train with a toothbrush dipped in Marvel Mystery Oil and then adjusting. And nothing changes. It's so nicely tuned that
it will happily idle at 250RPM, and it'll pull a five-foot hog uphill through waist-high grass in second gear without complaining, so I finally just accepted that it was part of this particular machine's personality
and stopped worrying about it...
 
"Sorry about the multiple postings. I'm new to this...Just didn't mean to offend anyone."

I wasn't offended, I just wanted to point it out before someone
blew up about it. Some people really seem to get ugly about it.

Bruce asked some good questions. Is it only at idle?

When you checked it with a light, did the advance work?

If it's only at idle and you pull the choke out a bit, I would
suspect it might actually get worse. My Jube with the loader
is a bit temper-mental on the carb. I have to enrich the
mixture for winter use and lean it for summer use.
Otherwise it makes some pretty strange noises in the summer.
I would call them a "burble" out of the exhaust, especially at idle.

A quarter turn in on the main needle fixes mine, but I don't
know if that's the same sound you are experiencing because
mine isn't occasional, mine consistently doesn't sound right
when that adjustment is required.
 

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