Tillotson KA6A Carb Info

[trident]

Anyone out there have any technical info or specs on the KA6A?

Seems to be little info available on this one...

Thanks.

Jerry Wienandt
Trident Racing

[Sonny]

lil bit

I sold a set of KA6A carbs a little while ago. From what I remember, There was 100 mark 75h motors built, 25 of that 100 were built in the alky configureation. The one's that were alky burners had KA6A carbs. The guy to talk to about that is Sam. He has forgot more about this stuff than I could ever hope to know.

[sam]

All MK75H's were alky-gas convert-able, there were no separate versions. There are 48 serial numbers open in the Merc serial number groups for 1959 that are at the Mk75H range, so it appears that there were 48 legitimate factory assembled 75H's. About that many prototype ID'ed mid sections and lowers seem to exist (they are slightly different from the production version and are marked differently), so it is fair to say that there are around 100 total.

Jerry are you trying to assemble KA6A's from loose parts or fabricate some usable clones?

The main dimensions are the same as most KA's: 1" venturi and 1 1/8" throat. I have a set and can measure the particulars of the nozzles if that is what you are looking for.

[trident]

Ka6a

Thanks, Sam.

Mercury shows a serial number range of 120070-120094 for 75H's.

I also understood that all production 75H's were convertible from gas to alky, that both sets of carb parts were included. Not sure what those parts were, though... was that different nozzles and idle tubes, jets or what? Not sure, even if these were fixed jet or adjustable as OEM.

I was looking for any info on drill chart sizes for the idle holes, etc.
I don't want to remove the welch plugs from the KA6A's I have to measure by sticking number drills in there... figured these are best left untampered with.

Wasn't planning to copy them, as I have no idea how I'd make those huge nozzles from scratch with the tools I have, anyway.

BTW, I do have a line on getting a copy of the 75H 'owner's manual', such as it was. I'm told this is just several pages of typed instruction info, similar to that supplied with some of the other ultra low production race motors. It was not a glossy cover manual like the 20H manual. I'll know more when I get it to copy.

Expect you already have a copy of that?

Jerry

[sam]

Yes, I have had a copy for some time. I also have the parts list, same hand typed list, not a printed item. One thing I do not have that is mentioned in the owner's manual is the lower unit disassembly/repair manual.

Several serial number plates have turned up with numbers higher than 1200094, but less than the next motor in production, the Mk15A which starts around 1200115. Some other older references give 1200065 as the starting number.

Only one unmolested block with the original fuel line set up has ever appeared. It is different from the fishing version and what racers usually did later on.

The only real difference on the carbs is that big main nozzle from a KC, just drill and tap to make a regular KA into an alky-convertable KA.

The carbs are much more rare than the mids, lower units and serial number plates.