9N wont start

Can't get my 1939 - 9N to start with the starter. If I pull it, it will start within 15' and run all day (or until out of gas in the middle of my wood lot). Will not restart with the starter if shut off or stalled. No smoke or issues when running.
History: Tractor sat for YEARS. I rebuilt the engine (new rings, pistons, liners) as when I would pull start it it would smoke up the whole farm. Dry compression is now 110, 110, 88, 112.
Converted to 12volts with new battery, alternator, etc.
I thought the old carb. was the issue so after rebuilding it x2, I bought a new one. Idles much better now but still will not fire or start with the starter button. The starter spins very fast. (The previous owner as an electrician and he put giant cables from the battery to the starter, etc.)
Has spark on all cylinders when I check with test plug.
Just to complicate things. Had to install 2 head gaskets as the #4 cylinder (112psi compression) "bubbles" into the water jacket under compression. I can hear it but it is not bad with 2 head gaskets. I will resleeve this winter.
Not sure why #3 cycl is low on compression. Will the low compression cause the starting issue??

Any wisdom and advice would be appreciated.

so #4 still leaks compression into the cooling system with 2 gaskets?

are you running 2 gaskets because you planed the head to try to get rid of bad surface and ran into interference.. or ?

Ps.. as to starting.. what's spark look like?

What does the spark look like?? Is it a good blue/white in color and does it jump a 1/4 inch gap or more?? If NO good chance your starter is going bad and pulling to many amps

Mark.......with #3 at 88psi, you claim #4 at 112psi bubbles into yer water jacket??? Better check yer hearing aides. And NO, a single low compression cylinder will NOT cause starting issues, low power maybe but NOT starting issues. That is one of the obvious benefits of converting to 12-volts, yer 6-volt starter spins FASTER and creates higher dynamic compression fer eazier starting. And NO, 12-volts on yer 6-volt starter motor does NOT damage yer starter motor. Some complain the faster spin causes Bendix problems slammin' into the ring gear. BTW yer starter Bendix must be squeaky clean. I rinse 'em with brake cleaner fluid 'cuz it leaves NO residue. As fer pull startin' yer 39, thats 'cuz yer BATTERY is dying. It ain't gott enuff AMPS to power BOTH the starter motor and sparkies at the same time. Do I haffta tell you to replace yer 6-volt battery???......respectfully, electrical Dell

Spark -- looked blue but thin/narrow not real "fat". I will double check later this week, after dark, with my 1/4"+ test plug.
Gaskets -- after resleeveing #4 would gush gasses into the water jacket. After 1-2 seconds of cranking water would erupt from the top of the radiator. I tore the engine out and readjusted that sleeve. (the block was machined by a previous owner to accept the thick wall sleeves but will not accommodate the top "lip" found on modern sleeves. A machinist friend machined the lip(s) off my new sleeves making straight sleeves -- that and some sleeve lock chemical and #4 has 112psi compression) I still had bubble issues with #4 but MUCH improved (remove that plug and all bubbles stop). The second gasket was just a quick experiment to fix the bubble issue completely, without having to pull the hood & oil pan yet again. I have done nothing with the head other than close visual inspection to check for cracks.
Thanks again for any advise soundguy- I am stumped.

Yep -- #3 is the low compression and #4 bubbles. Take out #4 plug - no bubbles with or without #3 plug in place.
Brand new 12 volt battery as well. The only way to start it is pull it... Has anyone ever had luck powering the start off their truck independent of the fully charged on-board battery to power the ignition?
Thanks!!!

"Converted to 12volts with new battery, alternator, etc. "

What kind of resistor(s) are you using? What happens if you bypass them? What happens if you bypass the ignition switch?

so to be clear.. with the double gasket, she does or does not bubble now?

What your asking is the correct way to jump start one that is 6 volts so as not to cause the battery to maybe explode. In theory if the starter is drawing to many amp that would get it to start since jumping it would not pull the battery on the tractor down. But you also may have a bad new battery. Seen that happen many times

I can still hear bubbles but just a little bit. A lot less than with just 1 gasket. Again good compression on this cylinder. Hope that makes sense.
Thanks!!

If it I still bubling, it could be contributing ti runtime issues is my main concern.

just checked the spark after dark. blue (some white little red). Jumps 1/4" it did fire 2x while im testing the spark.

ok.. getting it to jump 1/4" is pretty good.

next, on 12v, how well does she turn over? should be fast.

does your choke flapper have the little hinged window?


And you say she starts fine on a pull.. correct?

12 vlt : starter turns very fast. With the old carb I had to pull it quite a ways to start. with new carb (it does have the flipper within the choke flap) it will pull start in 15 feet or so. runs great all day. Bit of an issue if i go from idle to full too quickly. Spits, coughs, and occasionally stalls. No luck with the starter at that point either.
Thank you for your help!

possible issues I see:

1, going from idle to throttle causes problems.

this could be 3 things.
1, bad advance
2, too lean ( pops like popcorn and stumbles upon throttle, and slowly catches up ) ( may make run hot and have white plugs )
3, too rich, gurgles and tries to stall like over choke then catches up. ( may make black smoke and soot up plugs )

lastly.. try this.

hotwire coil directly from battery and try to start.

it may be that you have an incorrect coil / resistor combo, and that during starting, you simply are not getting enough primary current at the coil for a good start. Pull starts take away the starter load ( and spin the engine faster too ).

lastly.. have you compression checked her? if she is low, she will have a hard tme starting on starter, but may pull start fine due to even faster engine rpms.

Hi again, thanks for the advice. option #3 - stumbles than catches up - black plugs, fits what she does. i will try feeding the coil direct next.

compression (dry) was about 110, 110, 85, 110 +/- on the 110s. i was going to check valve clearance on #3 if direct feeding the coil fails.

Also, with the new carb i don't need to pull it near as fast as i did before.

Thanks again. This tractor runs so good, it is just frustrating that i cant use it in the woods unless someone is there to pull start it with me.

if she is too rich, try leaning her a hear.

Nailed it!!! Fed the coil direct from the battery, starts right up!!! Thank you for the suggestion, fought that for 1 year. Too much resisters?? If so, what do i do about that? Thanks Again!!