On Tuesday, March 4, 2008 at 6:58:00 PM UTC-5, wrote:
Hello all,
I have just purchased an older Starcraft 18' runabout that
currently has a 120hp 4cyl Merc gas engine coupled to a series 120
Merc I/O drive. I intend to convert this package, using the I/O, to
diesel using a 52hp 1.6L VW diesel engine in place of the merc 4 cyl.
Due to the relative unavailability (and cost) of a wet exhaust, I
intend to use a dry stack, and run the diesel with a radiator normally
found in the VW vehicles...side mounted and all tucked into a rear
engine box
that will be manufactured to allow adequate breathing and heat
dissipation. My question is regarding the pump system in the I/
O...can I just remove the impeller, or should I direct its output into
an open circuit back into the bay? Does the pump in the I/O have any
cooling or lubricating capacity for the unit?
This project is intended to provide for a work boat used in Coos Bay,
Oregon, for non commercial fishing and crabbing. Reliability and
economy of use are considerations.

what about the omc method ? using the impeller to pump water into a heat exchanger made like a pipe with tubes running through it. still have water pump and use antifreeze.as far as exhaust go`s make a triple wall pipe setup like you use on fire places, just smaller. i made one out of pipe and insulation before.

On Sun, 2 Aug 2015 14:41:36 -0700 (PDT),
wrote:

On Tuesday, March 4, 2008 at 6:58:00 PM UTC-5, wrote:
Hello all,
I have just purchased an older Starcraft 18' runabout that
currently has a 120hp 4cyl Merc gas engine coupled to a series 120
Merc I/O drive. I intend to convert this package, using the I/O, to
diesel using a 52hp 1.6L VW diesel engine in place of the merc 4 cyl.
Due to the relative unavailability (and cost) of a wet exhaust, I
intend to use a dry stack, and run the diesel with a radiator normally
found in the VW vehicles...side mounted and all tucked into a rear
engine box
that will be manufactured to allow adequate breathing and heat
dissipation. My question is regarding the pump system in the I/
O...can I just remove the impeller, or should I direct its output into
an open circuit back into the bay? Does the pump in the I/O have any
cooling or lubricating capacity for the unit?
This project is intended to provide for a work boat used in Coos Bay,
Oregon, for non commercial fishing and crabbing. Reliability and
economy of use are considerations.

what about the omc method ? using the impeller to pump water into a heat exchanger made like a pipe with tubes running through it. still have water pump and use antifreeze.as far as exhaust go`s make a triple wall pipe setup like you use on fire places, just smaller. i made one out of pipe and insulation before.


Years ago lobster fishermen on the Maine coast used a somewhat similar
system, except that the auto engine drove a normal propeller and
shaft.

They used a "keel cooler" made of about 1 inch galvanized pipe, and a
small header tank. The normal engine pump circulated the water. Hot
exhaust was straight up, usually with a perforated steel "jacket" to
keep your hands off the hot stack. They even used the normal car gear
box. High gear for forward and reverse gear - at full throttle to back
up :-)

I knew an old fellow that had been fishing lobsters for something like
70 years if that was the way to go and he said that if you had been
fishing out of a "sloop" it sure seemed like progress :-)
--
Cheers,

Bruce in Bangkok