1948 Farmall Cub - stored and not running

[Jimmymike]

Thanks Mike, compression is my next check. Just got to get off my behind and go buy one that will work with the tractor. Probably will do that today.

[Eugene]

The #1 is firing about 3/4" past TDC on the crank pulley. Is this correct? Should it be firing at TDC when cranking?:

Should be be firing at TDC at engine cranking speed. If you have a magneto it should go to full advance at around 250 engine RPMs.

All though, if the ignition system is firing a bit late, after TDC, and everything else is correct, engine should be running.

Standard battery powered ignition system, the advance will move forward, prior to the pointer, as the engine RPMs increase.

[Rick Spivey]

Based on description, I wonder if it is possibly 180 degrees out of time. It is really easy to do, might want to double and triple check. Otherwise, it should be running by now. Are you getting a distinct "click" of the impulse coupling in the magneto with each revolution?

[Jimmymike]

Based on description, I wonder if it is possibly 180 degrees out of time. It is really easy to do, might want to double and triple check. Otherwise, it should be running by now. Are you getting a distinct "click" of the impulse coupling in the magneto with each revolution?

Yes it's getting a distinct click on each revolution. I marked the as found position of the mag and then followed the instructions in the Farmall Maintenance manual to set the timing. After getting the #1 to TDC the timing mark and pointer aligned. I then moved the mag away from the engine block the mag clicked at the same point that I had marked it. I have not removed the mag since I started messing with it but not sure of the past history. I'm new to magnetos so I hesitate to remove it but I have a feeling like you stated that it could be 180 out. The gentleman I bought it from is a little forgetful so the past history is a little sketchy.

[Rick Spivey]

I am assuming you marked the position of the mag housing relative to the block. And having the pointer in position is correct. But internally, does the mag rotor point toward the #1 tower on distributor cap when #1 cylinder is at TDC. It actually will point slightly ahead of it if the impulse hasn't tripped, and slightly beyond it once the impulse trips. But it would be easy to see is 180 out. Since the mag lugs are 180, it is possible to install 180 out. I also am assuming that you verified the rotor was timed to the pinion gear, using the cast "scribe" line on the rotor, and the cast "dot" or "triangle" on the pinion. You cam check my first suggestion without removing mag, but if rotor timing off, need to remove and correct.

[Jimmymike]

I am assuming you marked the position of the mag housing relative to the block. And having the pointer in position is correct. But internally, does the mag rotor point toward the #1 tower on distributor cap when #1 cylinder is at TDC. It actually will point slightly ahead of it if the impulse hasn't tripped, and slightly beyond it once the impulse trips. But it would be easy to see is 180 out. Since the mag lugs are 180, it is possible to install 180 out. I also am assuming that you verified the rotor was timed to the pinion gear, using the cast "scribe" line on the rotor, and the cast "dot" or "triangle" on the pinion. You cam check my first suggestion without removing mag, but if rotor timing off, need to remove and correct.

I did mark the block and mag before moving the distributor towards the block. But I do not recall checking the position of the rotor relative to the #1 tower on the distributor cap. I have not removed the mag since I've owned the tractor, but my friend (previous owner) recalls that he had some "experts" trying to get it to start several years ago without success. I will go back and verify rotor to pinion gear (I feel good about that being correct), recheck timing with the rotor position relative to #1 on cap, and compression test before doing anything else. I may have to hold off for a few days since the tractor is parked in my equipment shed and not in a garage. We in Southeast TN are just not used to 7 degree F. with the wind blowing 10 to 15 mph. Spring hopefully is coming in about 30 days .

[gitractorman]

Assuming the tractor started and ran before makes it unlikely (not impossible) that the mag is out of time. I'm leaning more towards the valves being stuck open and not allowing the cylinders to pull fuel into the engine. If the engine was not stored with fogging oil, a little bit of corrosion, condensation, carbon, dirt, etc., in the valves could easily have seized them in place. I'd pour some Sea Foam in the spark plug holes, and open the valve cover to see if the valves are moving when cranking the engine. If the exhaust valves are coated with carbon, which is VERY likely since the tractor was a trailer queen, and not run often or ever worked hard, I'd bet the valves are just gunked up and not seating. The good thing is that spraying Sea Foam, or their other product, Deep Creep into the spark plug holes should dissolve the carbon and lubricate the valves a bit, and she should come to life without having to turn any wrenches. After getting it started, I'd run a strong dose of Sea Foam in the gas and take her out and work the snot out of her! My guess is she will start running better and better each time you run her.

[Jimmymike]

Well I finally got a chance to work on the ’48 again. I removed all the plugs and checked the compression. Pretty dismal; 50 in #1, 60 in #2, 55 in #3, and 90 in #4. Squirted a small amount of engine oil in each cylinder and checked again. Cylinders #1, #2, and #3 came up a little, maybe 10 or less psi. and #4 shot up to 115psi. Thinking stuck valves I removed the tappet cover and observed while cranking. All valves seemed to be moving up and down OK with no signs of sticking but could have carbon around the seats. I shot a good amount of Sea Foam / Mystery Oil mixture in each cylinder and turned over the engine several times to get a good coating on the piston rings and valves. Replaced the spark plugs and wires, verified the rotor button and timing once more and gave her a try, nothing. Not wanting to take the magneto apart to rotate 180 degrees (never took one apart before) I advanced the spark plug wires in the distributor two places just to see if that would make a difference. The engine turned over a half a turn and fired to life. It really ran great! Of course it was burning off all the Sea Foam and Mystery Oil I shot into the cylinders but after that she just sit there and purred like a happy kitten. Oil pressure was good and amperes was showing good charging. Ran her until she came up to operating temp and quit for the day. I guess now I will have to go into the mag and reset it 180 degrees to get my wires back into the proper position. I’m also going to check the compression again after running the engine for a while and see what the change is. Just by the way she run I’m pretty sure all the cylinder pressures will be up now. Many Thanks for all the advice and help! But, I’m not through checking everything out so I’m sure I will have other questions later.

[Barnyard]

Congrats on the success. You shouldn't have to get into the mag too much. Sounds like you just need to pull it and rotate the rotor and shaft 180º as you said and put the wires back in order. I would also run a can of Seafoam in the gas to help clear it up more.

[Stanton]

Congrats on getting it fired up! Now, enjoy it!

Always happy to see the forum help someone out and getting answers.

[Rick Spivey]

Based on description, I wonder if it is possibly 180 degrees out of time. It is really easy to do, might want to double and triple check. Otherwise, it should be running by now. Are you getting a distinct "click" of the impulse coupling in the magneto with each revolution?

Glad you found it! As Bill said, just pull magneto, rotate drive coupling 180, re-insert. re-time, and you're good to go. Sometimes I get it right.....

[Jim Becker]

If you had to move the wires 2 positions, you will need to rotate the magneto drive a full revolution, 360 degrees to get everything back to normal. The other option is to leave the magneto in place, remove the rotor and reinstall it 180 degrees from the current position.

[Rick Spivey]

Wow, right after I said I get one right....Jim caught us, you do have to turn a full revolution. Sorry!

[Jimmymike]

I haven't re-timed the magneto yet but Sunday was such a beautiful day I had to get the tractor out and drive it for the first time (e.g.; all I could do before is push it.) Everything works as it should lights, hydraulics, power take off, and clutch / transmission. The brakes chatter somewhat but that may be from sitting so long. I live in hilly (mountainous) SE Tennessee so getting a chance to drive under a good pull in all gears is not a problem. The tractor pulled well and the governor seemed to be working great. Generator was charging (30 amps) and the tractor ran cool without heating up under a small load. The only problem I encountered was when the tractor was idling for longer that 30 seconds the engine would just stop. The engine would not run rough before stopping, surge, just stop. It would crank right up and again just to do the same. But when running (moving) up and down hills in each gear it never coughed or hesitated, ran beautifully. I do think the timing is off somewhat and I will rotate the magneto and re-time but, what would cause it to just stop running at idle when it is running so smooth? It's getting a good flow of filtered clean gas fortified with Sea Foam. But, I do have a good load of Sea Foam in the gas right now, could that be a problem

[Dale Finch]

......It's getting a good flow of filtered clean gas .......

Do you have an in-line fuel filter added? If yes, perhaps it is restricting fuel flow just enough at the low idle to shut it off. Just a thought.

Or even the factory screen in the carb inlet? Good luck.