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.

On Tue, 4 Mar 2008 15:58:00 -0800 (PST),
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.

Many years ago the lobstermen on the Maine coast used automobile
engines in their boats. They used a "keel cooler" consisting of
several lengths of galvanized pipe. the system was fresh water only
and used the original auto water pump. Even used anti-freeze in the
winter time. A much more effective system then a radiator. After all
if you have the whole ocean to cool the engine why use a less
efficient medium?


Bruce-in-Bangkok
(correct email address for reply)

I have no idea what tree you have been living in, but your idea makes no
sense. In the first place wet exhaust manifolds for the VW diesel are
readily available from Pathfinder Engines and others. The modern VW diesel
makes in excess of 100 HP, not 52. Dry exhausts are a real fire hazard and
an unecessary risk. Keel cooling is a very good idea and is more common in
fresh water than salt, however you will still require a 5 liter or so
expansion tank.
Steve


wrote in message
...
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.

On Mar 5, 6:43*am, "Steve Lusardi" wrote:
I have no idea what tree you have been living in, but your idea makes no
sense. In the first place wet exhaust manifolds for the VW diesel are
readily available from Pathfinder Engines and others. The modern VW diesel
makes in excess of 100 HP, not 52. Dry exhausts are a real fire hazard and
an unecessary risk. Keel cooling is a very good idea and is more common in
fresh water than salt, however you will still require a 5 liter or so
expansion tank.
Steve

wrote in message

...



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.- Hide quoted text -

- Show quoted text -

Well, Steve, the tree I live in is the one behind my machine shop.
The reason that I will not put a wet stack on the boat does, in part,
involve the 488 pounds that the British Company sells them for (I
don't know how much that is in real money, but suspect it is in excess
of $1000US). Secondly, I have a few of the 1.6L diesels in my
inventory, and as I will not water ski behind the boat, I think 52hp
is adequate to my task, and more reliable and fuel efficient to boot
(I've rebuilt ten of these little engines in the past 5 years)...In
fact, if I had one of the newer diesels available to me, I would
still use the 52hp model. As the boat (18' open runabout, aluminum
hull) will be both trailered and occasionally beached on sand bars,
and as I don't want to pierce the hull or transom to build a cooling
system, the close-coupled radiator system mounted on the injector pump
side of the motor looks like a viable method, and the system's entire
footprint will
be less than 32" wide....Oh, did I mention that this was to be a work
boat? What I am looking for is reliability, safety and fuel
efficiency...speed, resale value, and the approbation of the boating
community are not issues.

On Mar 5, 3:53 pm, wrote:

Well, Steve, the tree I live in is the one behind my machine shop.
The reason that I will not put a wet stack on the boat does, in part,
involve the 488 pounds that the British Company sells them for (I
don't know how much that is in real money, but suspect it is in excess
of $1000US). Secondly, I have a few of the 1.6L diesels in my
inventory, and as I will not water ski behind the boat, I think 52hp
is adequate to my task, and more reliable and fuel efficient to boot
(I've rebuilt ten of these little engines in the past 5 years)...In
fact, if I had one of the newer diesels available to me, I would
still use the 52hp model. As the boat (18' open runabout, aluminum
hull) will be both trailered and occasionally beached on sand bars,
and as I don't want to pierce the hull or transom to build a cooling
system, the close-coupled radiator system mounted on the injector pump
side of the motor looks like a viable method, and the system's entire
footprint will
be less than 32" wide....Oh, did I mention that this was to be a work
boat? What I am looking for is reliability, safety and fuel
efficiency...speed, resale value, and the approbation of the boating
community are not issues.

He probably means the VW TDI engines, which need a computer to run,
and provide much less that 100HP on marine applications, (@2750 RPM,
aprox.). I googled 'vw wet exhaust', and here is a link to a wet
exhaust you could use for much less weight and cost that you state:
http://www.frenchmarine.com/Content.aspx?Content=9

Embedded are links to particular products and also to VW's SDI engines
(I guess they are direct injection, not computer needed).

The reason I mention the computer is that is a really bad idea to have
essential electronics that close to salt water.

On Wed, 5 Mar 2008 09:53:22 -0800 (PST),
wrote:



Well, Steve, the tree I live in is the one behind my machine shop.
The reason that I will not put a wet stack on the boat does, in part,
involve the 488 pounds that the British Company sells them for (I
don't know how much that is in real money, but suspect it is in excess
of $1000US). Secondly, I have a few of the 1.6L diesels in my
inventory, and as I will not water ski behind the boat, I think 52hp
is adequate to my task, and more reliable and fuel efficient to boot
(I've rebuilt ten of these little engines in the past 5 years)...In
fact, if I had one of the newer diesels available to me, I would
still use the 52hp model. As the boat (18' open runabout, aluminum
hull) will be both trailered and occasionally beached on sand bars,
and as I don't want to pierce the hull or transom to build a cooling
system, the close-coupled radiator system mounted on the injector pump
side of the motor looks like a viable method, and the system's entire
footprint will
be less than 32" wide....Oh, did I mention that this was to be a work
boat? What I am looking for is reliability, safety and fuel
efficiency...speed, resale value, and the approbation of the boating
community are not issues.

For what it is worth:

Nearly all of the commercial fishing boats here are powered using a
large truck engine - say 200+ H.P. equipped with a marine gearbox.
Cooling is through a sea water to fresh water heat exchanger using a
centrifugal pump (mounted below the water line) to circulate seawater
and the normal engine cooling pump for the freshwater side. Used
seawater is vented overboard.

The standard exhaust manifold is used connected to a vertical hot
exhaust which normally has a wire mesh protector.

I mention this because fishing boats usually are fitted out using the
cheapest method that works and none of them use a radiator...

Having said that we did have three oil production barges in the Java
Sea and the generator sets used radiators. As these units were
oriented with the radiators pointing outboard and the fans blowing out
they worked pretty well but a radiator does put out a large amount of
hot air.

So... your idea will work but for whatever reason people that use
boats for a living do not to it that way.

In closing, it is pretty easy for any competent welder to make a water
cooled exhaust manifold.


Bruce-in-Bangkok
(correct email address for reply)

On Mar 5, 8:16 pm, Bruce in Bangkok wrote:
On Wed, 5 Mar 2008 09:53:22 -0800 (PST),
wrote:





Well, Steve, the tree I live in is the one behind my machine shop.
The reason that I will not put a wet stack on the boat does, in part,
involve the 488 pounds that the British Company sells them for (I
don't know how much that is in real money, but suspect it is in excess
of $1000US). Secondly, I have a few of the 1.6L diesels in my
inventory, and as I will not water ski behind the boat, I think 52hp
is adequate to my task, and more reliable and fuel efficient to boot
(I've rebuilt ten of these little engines in the past 5 years)...In
fact, if I had one of the newer diesels available to me, I would
still use the 52hp model. As the boat (18' open runabout, aluminum
hull) will be both trailered and occasionally beached on sand bars,
and as I don't want to pierce the hull or transom to build a cooling
system, the close-coupled radiator system mounted on the injector pump
side of the motor looks like a viable method, and the system's entire
footprint will
be less than 32" wide....Oh, did I mention that this was to be a work
boat? What I am looking for is reliability, safety and fuel
efficiency...speed, resale value, and the approbation of the boating
community are not issues.

For what it is worth:

Nearly all of the commercial fishing boats here are powered using a
large truck engine - say 200+ H.P. equipped with a marine gearbox.
Cooling is through a sea water to fresh water heat exchanger using a
centrifugal pump (mounted below the water line) to circulate seawater
and the normal engine cooling pump for the freshwater side. Used
seawater is vented overboard.

The standard exhaust manifold is used connected to a vertical hot
exhaust which normally has a wire mesh protector.

I mention this because fishing boats usually are fitted out using the
cheapest method that works and none of them use a radiator...

Having said that we did have three oil production barges in the Java
Sea and the generator sets used radiators. As these units were
oriented with the radiators pointing outboard and the fans blowing out
they worked pretty well but a radiator does put out a large amount of
hot air.

So... your idea will work but for whatever reason people that use
boats for a living do not to it that way.

In closing, it is pretty easy for any competent welder to make a water
cooled exhaust manifold.

Bruce-in-Bangkok
(correct email address for reply)

It really doesnt take a competent welder to make a water cooled
exhaust, just some time and some pipe. That said, the shrimpers
around here often run a hot dry exhaust with no mufler...much to my
displeasure in the morning as they run by the house at 5AM and I am
trying to sleep. But it does work fine and reliably.

As to the cooling, the radiator idea really stinks. A heat exchanger
is also something that can be manufactured in the garage, its not
rocket science. The keel cooler however is the best idea and they are
used extensively in the shrimping fleet. For a 52 HP diesel the size
if the cooler is not excessive, probably a couple of 1.5" copper pipes
4' long would do the job. But I am not an marine engineer so dont
take my word for the size. I have a 50 HP Volvo Turbo charged 3 cyl
diesel in my 25' Albin and the heat exchanger is very small. I would
adapt one from something else. Just do a search on EBay for "Heat
exchanger" and look for one with a physical size and price that you
like.

On Mar 4, 6:58 pm, 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.

I don't think that the cooling circuit has any impact on the lower
unit. I'll check with the Mercury dealer here tomorrow and repost.

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