It always amazes me how many old Bobcats are still out there, running! My old one is very close to being completely disassembled, repainted and restored to original looks. Depending on what you use your Bobcat for you may get years of life out of it. An M444 would be a real oldie, but just fine for those home projects. A neat thing about them is that they don't sould like the later Bobcats, but have that tractor chugging sound that's not as annoying. Good mention about jackshaft bearings, they go bad from age and corrosion, and make a rumbling sound when in use. The biggest problem with these old machines is being able to get them apart due to all the rust. On my M610 it is impossible to see the jackshaft without removing the seat but as an alternative you can look at your voltmeter/ammmeter if it works and see if the shaft is turning as the alternator is connected to the jackshaft not the engine. Also with no power going to the jackshaft the hydraulic pump will not be working. Try moving the lift arms or bucket when the machine does not turn, that will show whether the belt is slipping.I have a 68 m444, just got it 3weeks ago, first one, after alot of this and thats, got it running. It has a speed control, and I found out that I have to bump it just off from the lowest speed and it will turn good then . If your drive belt is wet with oil then it is slipping and wont turn. Watch your jackshaft behind your seat while turning if it stops or like really slows down and belt is flopping up and down it will not turn. Had to do some adjusting on my clutch disks as well, reverse disks too tight and wanting to go back instead of forward. Have to replace both forward disks one very weak /worn. You will have to get things pretty darn good and close/ fine tuning so to say. So far I had to do the valves, carb,right jackshaft bearing, points/condensor,and lots of little things just to get it to run. And I dont have alot of money tied up in it. Remember that these are old machines and dont have the stuff that the new ones got..Good luck, you will get it going, just takes some time and patience..