Hard to start

Dell had some real good points on the MMO, too...
I'd stay away from converting to 12V, if it was me (and that's just my personal opinion, I don't know as there's any basis to it, I'd just stick with 6V... and my '50 8N is 12V).
I've seen the "12V band-aid" that 313 mentioned (a friend of mine has one on his '55 MF TO-35). If you don't mind driving the 3 hours every couple of weeks to recharge the battery (depending, of course, on your folks' use), that'd work too, I suppose...

HTH
Steve

Like dell says.. stay away from electronic ignition and front mounted 6v N's.. it's real problimatic.. especiallt on a tractor that will set a while and let the battery get low.

Perhaps they need a small 6v charger that can be put on for a few hours befor ethey go to start it.

Also.. those connections need to be clean bright and tight... use good soft fresh copepr core spark plug wires.. and al 437 or ch h12 plugs.. no resistor wires or plugs.

Ensure the points are gapped correctly, etc.

Soundguy

Most likely the carb kit you found was for a tsx 33 or tsx 241.. MS carbs... those zienith replacements were different beasts. Luckilly though.. if you wanted to.. the m/s repro style carbs are for sale everywhere.. even TSC.

Also.. if you bought your wires from the NH dealer.. they are the wrong wires.. they will be resistor/carbon fiber wires.. not copper wires like TSC would sell. Nh only stocks one basic wire type.. and uses it as a 'fits-all'.

Re-build/replace the carb and get the correct wires on there before you even think about doinf a 12v conversion.

There are carb specialty shops on the internet that can get you a rebuild kit if you can find your carb number..

Good luck

Soundguy

For the mechanically challenged, who don't want to do a $1500 engine overhaul for occasional tractor brushoggin' use, a $150 12 volt conversion can be a compelling reason.

And STAYAWAY from electronic ignitions for squarecan frontmount ignition systems.

Engine smoke is NOT VALVES, its rings. Me? I'd at least do a Marvel Mystery Oil treatment ($5 cheap) to make certain your rings are NOT STUCK. Seldom used OLD TRACTORS get sticky rings and loose their compression.

Just add about 1-tablespoon of MMO to each sparkie hole (crank the engine for a couple of strokes to spread MMO around, wait for a day to give the MMO a chance to work before you start the engine) Pour the rest of MMO into the current crankcase oil and run the engine for about 1-hr, then change the oil and filter while HOT. After you change the oil, check your compression again..... ...respectfully, Dell a 12 volt advocate for the right reason

That said, I haven't found the right reason for my easy starting 6 volt 52 8N, and I know how to do it right the 1st time.