K&B .61 Mounting Lug Marking

[Philip Oestricher]

I have a K&B .61 with the letters M.O. stamped into a lug rather than a serial number. Its exhaust stack is an 1/8 to 3/16 inch shorter than a stock .61 that I own. It is a ringed engine with a remote needle valve. Can anyone tell me the significance of the M.O. marking? Is this some sort of special purpose engine? Thanks for any help. Phil

[MECOA]

MO is MD if you look closely. MD = ModelerDirect

Before MECOA bought K&B they started Modeler Direct to sell off inventory and hence they marked a lot of the items sold thru Modeler Direct with an MD

As for the shorter lug. Someone at the old K&B decided that the exhaust should be shortened to allow better access to the mounting lug screws and they also went to a 6-32 thread rather than the 5-40 used before.

Check your screw thread and see if they are the same old and new. Also do you have the newer muffler design?

[Philip Oestricher]

You're right - the marking is "M.D." but the D was only partially stamped and I thought it was an O. The screws in both mufflers are 5-40. The two mufflers are identical but I don't know what difference there is between "old" and "new." Thanks much for answering my query.

[Philip Oestricher]

OK, now I know what the "old" and "new" .61 mufflers look like. Mine are both of the "old" style. The longer exhaust engine has the square carburetor and the M.D. engine has the finned carb with the remote needle valve. Thanks again for the help.