I need your help once again, I went and started my 48 Super A the other day and it literally sounded like a race car engine, then it would purr like it should then run rough again, so I drove it around to the shed and it still had good power just sounded really bad, like it was only on 3 cylinders, today I removed the valve cover and saw a valve that was stuck, turning it over with the hand crank it wouldn't move, I took the rocker arm assembly off, sprayed PB Blaster around the valve and spring, then lightly tapped the end of the valve with a rubber hammer and it popped back up, not had time to start it back up. What would you guys do? I had a similar problem on my JD A when I put a used head on, a valve was sticking, a little PB Blaster and a few taps and its been going good ever since, not sure if it would work on this one or not, I'm not much of a motor mechanic ) I ran this tractor several hours last week so it has been ran lately.