more engine possibilities and problems
- There are some other things you can do to get a cheap inboard
engine. One is to haunt the catalogs and ebay for a deal. Every now
and then Kubota (which makes the lightest Diesel engines I have
found) will offer a "special." I paid $1,300 for my D722N about
five years ago direct from Kubota. A friend of mine down in
Bradenton bought two of them for $2500 from some surplus outfit..
they run good. Of course they were bobtailed with no clutch or
transmission. I recently saw a deal on Northern Tool where they
were selling some kind of Japanese engine about the right size
pretty cheap. There are also surplus military engines but most of
them are air cooled and air cooled engines clatter... particularly
ones with aluminum fins... they ring like a child beating on a tin
bowl with a soup spoon. You can also haunt the eBay.
I would stay away from Atomic Four engines. They are heavy and weak.
For a keel cooled engine, it is best if it isn't a marine engine
anyway. You want an automotive style centrifugal water pump and
there is no need for a water cooled exhaust manifold or oil cooler
and certainly no need for a heat exchanger. Any stand-alone
transmission can be adapted to any engine. You can even adapt those
like old Volvo MD series which use crankcase oil in common with the
engine. There are usually two Hurth transmissions on eBay at any
time. They are very light and good. The reason for the belt drive
is to get exactly the right ratio to turn the propeller that fits
the cavity. One to one on a 3,600 rpm engine won't do it. The
ratio on my Rescue Minor is 4 to 3 and that has proven to be just
Weston Farmer had plans for how to modify an outboard motor to be
used as an inboard. What you have to do is lay it on its side and
turn the carburetor ninety degrees so the float bowl is on the
bottom. It only works for two cycle engines, though.... unless you
could figure out how to run a four stroke dry sump style... dang.
I have had a little experience with hydraulic motors. They are too
low speed for small boat use. If you had to turn one 2,000 rpm, the
friction on the oil in the lines would sap a lot of power (it is
hard to turn the shaft on one with your fingers). Not only that,
but even in slow speed operation like woring the cylinders on a
backhoe hydraulic oil gets hot and that indicates a lot of waste. I
believe direct mechanical drive is the best way to propel a boat and
I also believe that flat belts are the most efficient way to do that
short of roller chain... dang.
Don't let yourself get frustrated by minor problems.