Ford 9N miss/backfire

1940 Ford 9N Standard 6V positive ground.

She stopped running last season. Since spring is here and I need to mow the pasture, I’ve:

1) jumpered around ignition switch.
2) replaced coil, condenser, rotor, cap, points, plugs, plug wires.
Old points looked decent – but point gap was nil. <sigh> This obviously was my original problem last year.
Points are set proper now. And I now know how to remove distributor w/o too much trouble.

3) firing order 1243 CCW

After all this, she would sometimes start, but ran with a lot of miss and backfire through the exhaust. Loud!

So, I thought it might be carburetor. Completely rebuilt carb – runs the same as before. No change. Still hard to start and runs w/miss and backfire.

I’ve read several threads about stuck valves, along with hints at how to un-stick them.

Question 1: Does it seem likely that a stuck valve is the problem?
Question 2: If so, what is the easiest first attempt to un-stick them (and second... and ...)? I do not have a lot of expertise in this or specialized tools.

A followup question would be: What’s the best way to keep the valves from sticking in the future?

Thanks in advance
 
Stuck valve likely? Yes. If you have or can borrow a
compression tester you can help prove/disprove that.

To unstick them put a little Automatic Transmission
Fluid in the cylinders and let it set. You can also
take the tappet covers off the side under the manifold
and spray everything down in there with ATF to free it up.
Your favorite penetrating oil can be used in place of ATF.

To keep them from sticking, run a pint or so of
ATF or 2 cycle oil in every few gallons of gas.
Others may have other ideas too, but this works for me.
 
Thanks!

I pulled the plugs and put some ATF in each cylinder - I'll let it soak overnight.

Plugs 1 & 2 were sooty/carbon black

Plugs 3 & 4 were wet w/fuel.

I haven't located my compression tester so I can't run a compression test.

We'll see how she does when I try again...
 
At least do the finger compression test on each cylinder.Put your finger over one plug hole at the time and spin the engine over--do all of them blow your finger off of the hole? Spin it over several times before trying to crank it--messy but it gets some of the atf out of each cylinder..clean the plugs good-best way is with small hand-held torch.
 
This morning, I did a "finger compression" test - each cylinder does pop my finger off, so if there was a stuck valve, the ATF might have done the trick?

I checked for sparky at each plug - found that plug wires 1 & 3 may not have had good contact - fixed that - but still wouldn't start.

I jumped the starter directly from a 12V battery - observing the positive ground polarities, of course, and she started but ran crappy. I pulled the plugs again and found 1 & 2 looked OK but fuel on 3 & 4. Hmmmm. Could it be?
Continuity check between distributor and plug 4 verified 3 & 4 switched at the distributor cap. (I've now marked plug 4 wire at the distributor cap. I obviously got them switched in one of the distributor pull/replace sessions.)

So, good news is that she is running again! I mowed for an hour (about all I can take in one session) to make sure all is working. When I put ATF into the fuel mix, I seem to have lost some power - is this expected?

In any case I think I'll try without in the next few tankfuls.

Thank you all for your help!
 
"When I put ATF into the fuel mix, I seem to have lost some power - is this expected? "

I don't notice a loss of power when I add it.
I did notice a little smoke out the exhaust when I got it too thick.
When that happened I just added more gas to thin it out.
Should work in your case too if the oil is causing it.
Glad to hear you got it going!
 
Doug, no you should not lose power because u added atf unless u really added too much--you would know if u added too much because it would smoke like a tar kettle..But, like u said use less or none next tankful and see what happens--did u clean or Replace the plugs?? And Yes, switching wires 3 and 4 is really easy to do, been done a jillion times before-some admit it, others don't..Glad u got it going..
 

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