C mod Merc?

[jeff55vDSH]

I need to know what the "prefered" carb is for the old Mark 30 mod motor. I thought most guys were using some kind of KB part number tillotson now. But I can't remember for sure. Anyone know what venturi size and/or part number to use?
Thanks.

[Trident]

Mark 30's came with AJ-49 or AJ-51... the larger carb some used is the
KB-2A.

They're like a scaled down KA series and are tunable in ways the AJ's aren't, as you can readily remove the main nozzle and idle tube. They had fixed jets, but a drilled, taper machined jet works as a needle seat, and the rest of the assembly, needle, packing nut, packing gland, is straight from the AJ's.

Then again, Sam's C Mod Merc titles and records were won with selected carefully tuned AJ-51's. Selected as in, some are machined better than others. Pick the nice ones...

Hope this helps.

[jeff55vDSH]

Great info. Thank you very much!