On Tue, 25 Oct 2011 16:25:05 -0400, "Ed Huntress"
wrote:



wrote in message ...

On Tue, 25 Oct 2011 15:24:32 -0400, "Ed Huntress"
wrote:



wrote in message ...

Greetings All,
I have a 12 foot aluminum boat that is rated for a 10 HP max motor.
I do have a 10 hp outboard but bone on bone joints in both wrists
makes it really painful to put the motor on. For years I have been
thinking about various schemes to put in a liquid cooled 4 stroke
inboard. One idea is to use a conventional air cooled flat head motor
that's been modified with a water jacket. I told Harold Vordos about
this idea and he had done it and it worked well. I mean the liquid
cooling conversion. He even had done it with a motor that was very
close to a 7 hp motor that I have and was considering. I have also
thought about using a 125 to 250 cc motorcycle motor. But these are
expensive and rev higher. I have several reasons for wanting to do
this project. Mostly I want a quiet power plant and a liquid cooled
engine inside some sort of housing seems like it would fit the bill. I
want 4 stroke mainly because I'm tired of putting oil in the water. I
also want reverse and am not sure what is the best way, at least for
me. The plan is to use a prop shaft that pierces the bottom of the
boat and a rudder. So the motor would be inboard as would the
reversing gear. Money is tight so don't suggest a Crosley engine. If I
could even find one for sale. Any thoughts?
Thanks,
Eric

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Many decades ago, single-cylinder inboards were used for some small fishing
and utility boats here in NJ. Horizontal-shaft motors typically used a
conventional shaft log, packed with tarred rope at the ends and made of two
planks screwed together. Vertical-shaft motors used a through-hull gasket
and a right-angle powerhead that looked like the bottom-end unit of an
outboard. In fact, that's what some of them were. The shaft-log types
didn't
have reverse, IIRC, but at least some of the through-hole vertical-shaft
units did.

'Don't know about cooling conversions. Most were air-cooled mower engines
and the like. Exhaust stacks went straight up around five feet. An
underwater exhaust is quieter, but not easy to implement.

Good luck. If you can pick up a cheap or free outboard with a shot motor,
most of your work is done.

I could even hack the 10 hp merc I already have or an old 5 hp that I
have but these are 2 stroke motors. I don't want to dump any more oil
in the water. I thought about using the lower unit from an outboard
with the reverse built in and just rotating for reverse or using a
plain lower unit and rotating 180 degrees for reverse. However, I like
the idea of a straight shaft and a rudder. And reverse is important to
me. I have three outboards and the big one has reverse while the small
ones just rotate 360 degrees. I like reversing. It really helps a lot
when it's just me in the boat. which is most of the time.
Eric

Well, the thought is that you would use the outboard bottom end and a
four-stroke motor, so the condition of the two-stoke wouldn't matter.

Those vertical-shaft conversions I mentioned did not rotate. If they had
reverse, it was a gear reverse in the lower unit. Some of the old ones, and
maybe those made today (I haven't looked) just shifted the pinion shaft from
one side of the bevel gear to the other with a fork. The pinion slid on a
splined shaft.

Regarding cooling, there have been all sorts of arrangements on old
outboards. I had a British Seagull outboard that had a water-cooled cylinder
and an air-cooled head. g
I mis-read your post ED. Your were talking about using the lower end
and somehow I read that you meant the motor. Oops. About weird
cooling, my neighbor had an outboard that cooled the exhaust with
water and the engine with air.
Eric