I have 1943 M that has sat for probably close to 35-40 years. The good news is that is has always been in a barn, all the parts are there and the motor is not locked up. The tractor was in good working order when it was parked (or so my grandfather says). I am looking for recommendations on how to approach trying to get the tractor started, what items you would initially replacement before trying to start it.
Thanks

Start with new oil I would drain the existing oil looking for coolant.

Drain all the oils (leave rear end oil in for now)& fluids, including gas if any left in the tank. Remove sparkplugs & fill cylinders with Marvel Mystery Oil and leave. Remove carb & place in a can of carb cleaner & allow to soak.

If tractor has a hand crank turn the engine over once a day & keep refilling cylinders with Marvel Mystery Oil. After carb has soaked buy a rebuild kit & rebuild it, being sure to clean gunk out of all passageways.

Crank engine over to remove MMO, then install new plugs, points & condensor , replace carb, & put new gas in the tank. Refill engine oil, replace oil filter, & fill rad. Finally, see if the old gal will start. If you can get it to run then drain rear end oil & replace with diesel fuel. Drive trac tor 1/4 mile or so, drain diesel fuel & put new rear emdoil in.

Good luck & have fun

I would also remove the gas tank and clean it also. Had one this summer that I would have been better off to do first.

couple other things i"d check too, pull the valve cover, and lube up the valve train real good with automatic trans fluid, check the valve train while cranking the motor over by hand to see if any valves are stuck. i"d also go over all the lube points on the tractor and give em a couple pumps of fresh grease, especially the water pump and the distributor. (there are 2 flat blade screw type plugs on the distributor, pull them out, screw in a zerk and give em a couple pumps. (i didnt do that on an m i did years ago and tore up a set of gears after the tractor was running. ) it was delco distributor.

Depends a lot on where you are in cold climates you will probaly have lots of codensation in engine and rear, in warm climate this is not a problem. I pullled cotton picker off 1940 M few years ago that had sat in open front pole barn for about 30 years. After checking out ignition putting oil in cylinders, changing oil and filter it fired right up and ran good. Had to pull frame cover to flip ring gear and there was not a trace of rust in rear end. Contrary to what everone says the only oil leak it has after being used several years is slight leak behind govener.

What is your suggestion on how to clean the tank?

Thanks for the suggestions. My major fear was how to lubricate the engine without have to tear it down, and it seems like you all have answered that question. Thanks. I hope to get started the first of next week.

One thing I do on the older tractors I buy is to remove the fuel sediment housing from the bottom of the gas tank & insert a piece of copper tubing about 1 '1.5" long and reinstall the housing. The tube puts the inlet up above the sediment in the bottom of the tank alleviating a lot of headaches. Can't remember the tubing OD, either 1/4" or 5/16" without going out in the shop & looking but you do have to drill out the inside of the aediment housing just a little to get a good tight fit.

Also drop the pan and clean it and the oil pump strainer.

Gordo

Easiest is to remove the tank & flush out with fresh gasoline. That will usually get out much of the old gas that has gummed. I once had a tank that had a lot of gum in it & someone suggested throwing rocks in it & tumbling the tank. Problem was the rocks stuck in the gum & stayed there while tumbling. I ended up putting fresh gas in it & let it sit for several days. I then tumbled the tank & drained the gas out. It had dissolved most of the gum & the rocks came out.

I have also heard of guys pressure washing the tank though I personally haven't tried it. If you do pressure wash it make sure you get all the water out before you put it back on.

For rocks, or bolts & nuts, to work, the tank can't have a thick puddle of goo in the bottom. The aggregate is to knock the rust loose; it does nothing for varnish or sludge.

Take it one step at a time. First get the engine running. For that you need to change the oil, clean and rebuild the carb, do a full ignition tune-up, and freshen up the wiring.

Being a '43, it's probably still a magneto ignition. All you really need to do there is clean up the contact surfaces on the points, and reset them to the proper gap. If it's a battery ignition, you can do points, condensor, cap, and rotor. Wiring will be more important on the battery ignition than the magneto too.

I would pull the tank and clean it before trying to start. It sat too long to not have crap in it. If you are all rammy and just "want to hear it run" before you do more work you could/will send a bunch of crap down to your carb. That fuel stainer is just for show...
It will take you about 30 min to take the tank off and have it back on. DON'T PUT ROCKS IN THE TANK!!! Use a CLEAN (NEW IS BETTER) chain or clean (NEW IS BETTER) nuts and bolts. You can never get a rock clean enough to clean your gas tank.
I wouldn't rebuild the carb first. You will probably crap up your new rebuild (esp if you don't clean the tank well) They will usually run (bad) on a bad carb, but they will run.
I would pull the valve cover and make sure things are moving up there. 30 years is a long time!
I would use the chain start method for your first try. You electrical system may still be up to par, but is it very unlikely. Put the dead tractor in 4th and the running tractor in 2nd or 3rd. I have used my F250 before as well. I wouldn't tune up the electrical system until after it runs. I would check it out before trying to start. Wires may be bad etc.
CHECK FOR OIL PRESSURE AFTER IT STARTS!!!

My advice. Being that that the motor is free and seems to be in good order do this. Ensure there is coolant in motor. If coolant in motor continue, if not fill with regular water (if your area isn't cold enough to freeze right now) and inspect. You might have a leak someplace. If leak is obvious and severe IE radiator core has major hole pull and consider replacement/repair but not immediately. If coolant disappears but no obvious leaks FIND IT. It's going someplace, might be in the crankcase. If coolant in crankcase ABORT it aint gonna run for long if at all and might have issues. If no leaks are present and coolant is in radiator leave alone for time being (more than likely the cooling system is going to need attention but it can wait).

Next pull plugs and pour favorite lubricant down hole turn over and let sit overnight. Repeat at least once more.

Pull valve cover pour favorite lubricant over valvetrain while turning motor over. Ensure valvetrain not binding AT ALL AND FREE. Let sit overnight and inspect. Repeat at least once more, valvetrain must be completely free or you'll be learning how to replace pushrods possibly more. After above steps more than likely junk has filtered down to the pan.

PULL PAN. Clean out pan and crankcase walls and oil pump pickup. These are bound to have junk in them after 30 years anyways.

Pull off carb and install rebuild kit. Seals and such are probiably dried out and no good JUST DO IT. Carb kit is cheap.

Inspect electrical and get it to a point where it will run safely.

As this point you can elect to pull the tank and clean it or just rig a temporary system to get the old girl breathing. I would more than likely just rig a temp system to get her running but it's up to you. You might find the tank rusted full of pin holes and in need of major repair. If you plan to immediately hook up the air cleaner tube pull the system COMPLETELY apart and clean it. If not you will suck whatever built a nest in the last 30 years into the engine. JUST DO IT.

Replace oil filter and refill crankcase with cheap oil (you won't want to keep it in there long if you get it running).

ENSURE TRACTOR IS IN NEUTRAL. I wouldn't trust or place my life or that of anyone else on the line with a clutch of that age that is unknown. Pull starting is a bad idea as far as I'm concerned reference above comment. It's possible that the disc is seized to the flywheel/pressure plate. Give the motor a spin with the starter and try to start it. If it fails to start determine reason for failure. IE spark/fuel/compression.

Once running keep a good eye on oil pressure. If no oil pressure within 5-10 seconds of running SHUT HER DOWN. Might be a bad guage might be no oil pressure. Find out which you got. Run her 5-10 minutes at low throttle and inspect engine temperature. If radiator is gone/rotted out shut down and evaluate next step. If holding water and no temperature suspect one of two things if not both. Bad thermostat or broken guage.

You initial objective is to see what kinda shape the engine is truely in. If the radiator leaks alittle so what fix it after you determine the tractor's worth it. I'd spend as little money on it as possible, just enough to determine the condition of the motor.

30 years is a long time and I wouldn't be surprised if you find alot of things have issues. Sitting tears em up just as bad and people running em everyday.

Once running and if your satisfied with the condition of the motor drain oil with engine warm (gonna look nasty). Pull the radiator (hopefully if you refilled it you could just put tap water in it to help with your disposal) and send it to a good reputable shop. Like I mentioned before it's probiably gonna need some TLC. Once radiator is back replace thermostat (guage if needed) and hoses and belts. They are dry rotted replace em. JUST DO IT.

Get the electrical right, probiably gonna need a new harness. Easy enough to figure out that one.

Pull tank and go over. I'd be tempted to just farm that out but you can try to clean it up yourself. If you clean her up yourself and find holes more than likely the guy you sent the radiator to will fix up your tank as well.

At this point minus tires etc I think it would be ready for it's trial voyage to establish condition of brakes/steering/transmission.

Thanks for the suggestions. You basically read my notes that I have been compling. I decided last night to ditch the tank for now and use a temporary tank to avoid any problems. I also agree I am not going to pull start the engine. I hope to get the tractor moved into the shop this weekend. I figure draining the oil is going to be the tell tale sign. I had also decided to replace the oil pressure gauge before I tried to start it. I will wait until after I inspect the radiator.