Reply To: 1947 Mercury KD4 gear case seals

[Buccaneer]

Thanks for your detailed reply Louis!
I comment within your reply.

The drive shaft seal on all models K1 thru KE3 and WA2 thru WG4
as well as the two Sea King singles is a piece of leather or raw hide.
Replacement can be using gasket punch. I can not recall ever finding
an old seal that was not rotted or missing entirely.

Whatever the rings of packing were made of, they crumbled into 100
pieces when I probed them. You have me curious as to what “raw hide”
actual is? Uncured hide perhaps?….. or a Western?

Drive shaft is ground on gear case end and is slightly smaller in diameter. If the larger end fits thru the bushing in gear case , the bushing is worn out. Both bushings in the gear are cast into the gear
case and can not be driven out. Boring out busing and pressing
in inserts and reaming would require a holding fixture so
the two bushings are in precise alignment.,,a lot of work for just one
gear case, Easy solution is good usable gear case from any og
the many models that shared gear case.

I ended up drilling the old worn out and out of round, 1-1/2″ long drive shaft bushing to 5/8″ dia.,
and made a bushing 2-1/2″ long, the bottom end of the bushing fits into the old bushing, and
the top 1″ of the new bushing is 3/4″ to fit the housing bore. On top of that I put a 1/2″ x 3/4″
seal, and custom made an alignment dowel to go atop of the seal, to align the gear case
with the mid section. “Line boring” was not an option, but I temporarily put it all together
and it seems to turn okay.

There were 3 different water pump designs, each will work with any of
the Early K Models and their Wizard and Sea King singles made by
Kiekhaefer. The propeller shaft, water pump cover and the retaining
spring will work with all, The rotating impeller design (3 slit water pump) are preferred as the oscillators are hard to come by. The
16 square hole and 7 slit water pumps are more complex and often
are missing small items.

This 1946 motor was originally the “wobbler” style water pump. It did seem to pump okay last Fall in the test
barrel…… not sure how, as the gear case was in sad shape.
I’m using 1947 rotary vane style pump housing, it’s prop shaft, but the gears from the 1946,
that were in much better shape. Both sets of gears for the prop shaft were the same 19 tooth count. I did
not count the teeth on the drive shaft gears.

The single cylinder models have a 12 tooth pinion on drive shaft and a 22 tooth gear on prop shaft. No shims or spacers.

The twins have 14 tooth pinion on drive shaft and an 18 tooth gear
on propeller shaft. PLUS two 0,010 steel shims on propeller shaft
ahead of the gear AND a 0.100″ bronze spacer above pinion gear
and a 0,010″ steel shim between spacer and bushing,
The steel shims are often rusted or missing along with the bronze
spacer. These parts are essential for proper gear spacing and smooth
operation. The gears will self destruct without the spacer and shims
properly installed.
Also note the 12/22 and 14/18 are gear sets…they are NOT be mixed.
Sometimes you find a twin with a single gear set or a single with
a twin gear set due to prior work. May overheat overcool due to water
pump being driven too slow or too fast.

I ended up with 3 thin steel shims below the prop shaft gear, and
a thicker bronze shim above the gear. This gave me good gear to
gear mesh with a hair of backlash, and a tiny bit of axial play on
the prop shaft. I think I luck out with the thickness of my new gear case
gasket.

Drive shafts often have worn splines or are pitted in area of seal and
bushing…drive shaft lengths vary so best to compare old and potential
replacement before purchase or assembly.

I’ll have to recheck the driveshaft out, to make sure it’s not too loose in
the power head, now that I plan to flip it end for end for a nice gear case
seal area.

The seal in 3 slit rotax rotating impeller type water pump have a difficult
to remove seal that is usually well past its Best By Date. Replacement
is a standard inexpensive item, but, first you have to get the old seal
out which may involve removing it a piece at a time.

The seal in the gear case cap I’m using appears to be a solid rubber
piece about 1/4″ thick, and in decent shape for reasons unknown.
The only 1/2″ x 3/4″ seal I’m finding over the counter is only 1/8″ thick,
but I have two coming, so suppose I could “double them up”

The early K Model Kiekhaefer outboards are well though out designs
but, they can have wear, corrosion and lost parts issues. Fortunately there are a wide range of years and models sharing the same or will fit
parts. Unfortunately cowls and spark plug covers are usually gone and
the available supply is thin, Complete and original examples are worth
a premium just to avoid a parts chase. Even a bare bones parts can be
made into runners that may someday find the rest of its partsl
Louis

Mine came with the front cowl, and spark plug covers, so I don’t feel
bad about paying $65 for a running Mercury, even if the gear case needed much
attention! Thanks!

Prepare to be boarded!