39 B questions

[RyaninKS]

I am getting ready to start reassembly of my B and ran into afew questions. 1. I started cleaning off my old pistons getting ready to put on my new rings and found the number 30 stamped on the top of each piston. not a .030 or anything that would mean it's 30 thousands over, and i put my standard piston rings in the cylinders and the gaps measured fine. Is there something i'm missing here? Are all JD pistons stamped with a 30? and 2. My governor is in desperate need of repair. I have a 41 B that i know has a good governor, will the guts out of the 41 governor fit the 39 governor? According to my parts book everything seems to be the same except the case and the magneto drive.

Any leads are appreciated Ryan

 

[Paul from MI]

Inner parts of the '41 governor should fit, but you may need to move the fanshaft gear to your original fanshaft and re-adjust the gear backlash.
Can't remember if the fanshafts are the same. If you change the impulse coupling on your mag or change to a short lug mag from your '41 you can keep the same drive coupling. Won't be original, but only you will know.
Paul