Vintage Mercury Racer ID Help Needed

[bayham3261]

New find today! I picked up vintage Merc racing engine from a guy who was cleaning up the “junk” as directed by his wife. He was as happy to see it gone as i was to get it. Looks mostly complete except for the covers. I’m guessing it was used stripped down. Engine is stuck so it will probably need extensive engine work or a replacement powerhead. I don’t really know much about these so some help with the ID would be great. – any other technical info would be appreciated too! I don’t seem to see any clear tags on the engine but there is some info on the magneto plate. Bendix: Model K2A-205, Serial 510809.

Based on the gold paint i assume that it is a mid 50’s model. Seems like it is a Class A engine (Mark 15?)… it just seems too small to be a Mark 20.

Are there any places on the outboard i should be looking for ID info? Thanks!

A little information is a dangerous thing!

[squierka39]

Someone smarter will chime in, but the MK 20 and MK 15 are dimensionally the same on the outside. Take a picture of the carb model, that might help the Merc experts also.

[bayham3261]

squierka39 wrote:

Someone smarter will chime in, but the MK 20 and MK 15 are dimensionally the same on the outside. Take a picture of the carb model, that might help the Merc experts also.

Thanks, I’ve take a few pics of the carb. I noticed a model # on the carb… AJ43A

A little information is a dangerous thing!

[outboard315]

There should be a serial number on top of the cylinders or on the flange separating the front and back of the block.

Yes the mark 15, 20, and 25 are dimensionally the same from the exterior. I am leaning towards a KH7 though. I think the fuel pump is bolted to the shifter boss since I don’t see a fuel pump boss on the opposite side. Not sure where it is pulling vacuum from though.

[bayham3261]

outboard315 wrote:

There should be a serial number on top of the cylinders or on the flange separating the front and back of the block.

Yes the mark 15, 20, and 25 are dimensionally the same from the exterior. I am leaning towards a KH7 though. I think the fuel pump is bolted to the shifter boss since I don’t see a fuel pump boss on the opposite side. Not sure where it is pulling vacuum from though.

Yes the fuel pump looked a little odd to me too. I just unbolted the pump and it looks like someone drilled a hole into the crankcase to scavenge the vacuum. I guess this is similar to what people do to convert pressure tank OMCs to a standard fuel pump setup. I couldn’t find any serial numbers on the block.

I’m getting the feeling that this outboard may actually be a bit of a Frankenstein build someone did. Whoever had this going was probably only thinking about how to go fast.

A little information is a dangerous thing!

[eltoquad]

The AJ43A carb came on a Wizard WK7 from 1954.

[A Hoskins]

Nice find. The block is likely from an early gear shift motor, KH-7 or the MK-15,20,or 25 as previously mentioned but the 15 and 25 motors did not usually have the Bendix magneto. The driveshaft housing and lower unit are valuable, you will be surprised. The fuel pump is mounted to the boss where spark advance linkage would have been mounted on these early gear shift motors. The threaded holes are not blind. That 1/2″ diameter hole doesn’t come across as a great idea. The home made Quincy dump makes me smile.

"Fox News" isn't.

[bayham3261]

Thanks! Interesting stuff… I wonder if it is a wizard that was bolted to a racing leg and gearcase. The tiny fly wheel seems odd to me. Was this factory?

What’s a Quincy dump? Nothing to do with the crime fighting coroner I assume…?

A little information is a dangerous thing!

[bayham3261]

Another question for the merc guys… What powerheads will fit this style racing leg and gearcase? I’m going try to find a donor powerhead. I have a really nice ’73 merc 200 powerhead but i’m sure that won’t fit… it would be funny if it did!

A little information is a dangerous thing!

[foot_doctor]

Some observations: The Bendix-Scintilla ignition would normally have come on a 20 cu. in. engine. The cylinder block is minus the horizontal bars that were on the MK15, 20, 20H and Mk25 blocks. The exhaust housing appears to be from a Mk20H. It has the flange below the carburetor. The gearcase is a sand-cast unit with the bushing tail cone. That was the earliest version of the Quicksilver lower unit, and originally came on the “Q” engines. The drive shafts in those were 2 inches longer than those in the “H” units, such as this engine has. My first guess it’s a “Cruiser” powerhead with a “Q” racing flywheel. All of the KG and KF 2-cylinder and Most of the MK 2-cylinder powerheads from the late 50s will probably fit. R.T.

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