The only Massey 55ís I find on Tractordata or Tractorhouse are Massey Harrisís made between 1946 and 1955. I assume that it is a Continental diesel engine, and from the photos I have seen that it is a gravity feed system to the injector pump. If you have eliminated air and debris from the fuel system and gotten good clean fuel flow from the bleeder nipples on the injector pump then the next thing to do is loosen the compression nuts at the injectors and turn the engine over to see if fuel is getting to the injectors. If fuel is getting to the injectors but you get no smoke from the stack at all then the injectors need to be pulled out and worked on. There are many other entries on this site explaining how to diagnose the problems as well. If it is the injector pump that is faulty it requires a nice clean bench somewhere with an experienced pump tech to fix it.
Years ago a friend of mine asked me to help him get a John Deere R Wheatland going after it had been sitting out for a while. I said what the heck and hopped on while he pulled me around the yard with his pickup. The wheels just locked up when I engaged the clutch even though I had it in high gear. It would not turn over. After a bit of head scratching and required cursing, we tried again only this time I pulled a lever on the left side of the dash, which I had no idea what it went to.
Boom Boom Boom, the 2 lunger took off with roar and a geyser of gallons of rusty water, which fell back to earth precisely on my head. I had opened the compression release valve. To add to the adrenalin rush the engine revs kept increasing even though I had pulled the fuel shut off lever. I frantically jumped off to look for the fuel shut off from the tank while my friend stood there laughing. The shut off was of course right above the spinning clutch drum, which added to the fear factor. The rated maximum RPM for that engine was 1000 and Iím sure it must have been turning 3600 before it shut down but it didnít blow and Iím here to tell the tale so thatís all good.
My friend still has the old girl and I am almost certain it has not been started since that rusty water day. If anyone is interested he lives northwest of Fort Worth Texas in a town called Paradise.