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I’ve been examining gear case parts between the 1946 (runner) and 1947 (parts) Mercury KD4,
and seeing what and if I could switch around using some of the best parts.
It appears I can use the 1947 gear case with the vane type water pump impeller (as opposed
to the wobbler style pump in the 1946) and the good gears from the 1946.The 1947 has a prop shaft seal of sorts in the gear case cap. It looks to be a solid rubber affair
about 1/4″ thick. The prop shaft is .500, and the seal OD appears to be 3/4″.
What have any of you used for a modern / better replacement for this prop shaft seal?Per the parts manual, the drive shaft seal, tension spring, and spacer are all missing
on the 1947. The 1946 has a brass sleeve with some packing in it, but the brass sleeve
doesn’t fit in the sleeve in the top of the gear case, so I don’t see how it even worked.
I don’t have a parts manual for this earlier gear case to see what suppose to actually
be there.
What have any of you used for the drive shaft seal for a modern / better replacement?
The drive shaft needs a new bushing. The worn one that I took out doesn’t
even look original. It appears someone drilled out the worn original bushing
and placed another bushing inside of it. The original bushing has a flange
(that the drive gear thrust washer rides on) that’s bigger than the bore.
There’s not enough room to drive the bushing out of the bore, into the
gear case, and with a flange on the bushing, it can’t be pulled out the
top side of the bore. How can this be?
The bushing is not shown on the parts list, so guessing it’s not meant
to be replaced.
I was thinking about machining another bushing to go on top
of the drive shaft bushing, and putting a modern seal on top of that….. if I
can find something of the correct OD.The drive shaft on these appear to be reversible, so I could flip the drive shaft
end for end and have a virgin seal area.Thoughts or tips on any of this appreciated. Thanks!
Prepare to be boarded!
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.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.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.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 19 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 14/19 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.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.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 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
Twin Gear Sets are 14/19 I stand corrected.Per Factory Specs MERCURY KD-4 should have left factory with a 3 Slit pump intake and a rubber vane type (ROTEX) impellor.
Why some one would swap out parts to older less reliable Oscillator (Hockey Puck) style water pump is a mystery?
I usually have the opposite problem? 1940’s K motors with newer 3 slit pump intake and rotex impellor, when the motor
Left the factory with 16 square hole intake, and oscillator style pump. Rumor has it that the 7 slot intakes were done by hand
Using a hack saw blade at factory?I’ll post some pics of Lou, “Green Thumbs” making seals from leather.
Don’t see any green Mercury paint on that thumb? LOLDrive shaft lengths vary both because Kiekhaefer did some strange things and because Wizards generally had a distinctive tower that was
taller than Mercury models. I bough a really nice drive shaft at
Suter Meet figuring I could use it on a Mercury I had under repair,
About an inch too long, It eventually was reunited with a Wizard.
I have several drive shafts that vary in length by less than an inch
and I know not why…Mr Kiekhaefer did things his way,
I took a couple night school classes in machining so I gave some thought to renewing the bushings in gear case that drive shaft and prop shaft ride in. It appeared to me that for the gears to mesh
properly their respective shafts would have to be in close alignment
which meant the bushings wold have to be in correct alignment
to each other. The only way I could see all that happening required
a device to hold the gear case while it was bored preferably on
a Bridgeport mill. You seem to have found a work around.
My solution to this sort of issue has been to use parts off parts motors
I have measured drive shafts, the ground end is something like
0.495″ while the unground end is about 0.500″ If both ends will
fit thru gear case bushing I look for another gear case. Not many
outboards got enough use to wear out so parts motors usually
have good usable parts. In Michigan not much boating activity
from Labor day to Memorial day,
Louis
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