I have a 26' Renken Classic cruiser that came from the factory in 1991
with a 5.8 liter Ford V-8 and OMC Cobra outdrive. The Y pipe
developed a big hole and I was obliged to remove the engine to replace
it. Now that the engine is out, I am seriously considering
replacement with a small diesel like the Yanmar 2GM20C. I do not need
a boat that planes as I have a smaller boat that does everything I
want for skiing and fishing etc. Also, the fuel consumption of the
Ford V-8 is very intimidating. I would be happier with a little
Trawler-like boat for gunkholing and weekend cruising. First question
is whether a 20-25 hp diesel would mate up well with my Cobra drive?
Can I use the existing Cobra cooling pickups and the Cobra gear
shifting mechanism? Can I feed the diesel exhaust back out the Y pipe
of the Cobra/Ford system? Is there maybe a better way to go to make
my cruiser into a less macho and more homey platform? All ideas and
opinions are welcome and appreciated.

Wayne

Something I read awhile back ... dunno if it's true ... due to the way a
diesel fires as compared to a gas engine, it would hammer your OMC (designed
for a gas) apart ... ???

"wgsant" wrote in message
m...
I have a 26' Renken Classic cruiser that came from the factory in 1991
with a 5.8 liter Ford V-8 and OMC Cobra outdrive. The Y pipe
developed a big hole and I was obliged to remove the engine to replace
it. Now that the engine is out, I am seriously considering
replacement with a small diesel like the Yanmar 2GM20C. I do not need
a boat that planes as I have a smaller boat that does everything I
want for skiing and fishing etc. Also, the fuel consumption of the
Ford V-8 is very intimidating. I would be happier with a little
Trawler-like boat for gunkholing and weekend cruising. First question
is whether a 20-25 hp diesel would mate up well with my Cobra drive?
Can I use the existing Cobra cooling pickups and the Cobra gear
shifting mechanism? Can I feed the diesel exhaust back out the Y pipe
of the Cobra/Ford system? Is there maybe a better way to go to make
my cruiser into a less macho and more homey platform? All ideas and
opinions are welcome and appreciated.

Wayne

Something I read awhile back ... dunno if it's true ... due to the way a
diesel fires as compared to a gas engine, it would hammer your OMC (designed
for a gas) apart ... ???

"wgsant" wrote in message
m...
I have a 26' Renken Classic cruiser that came from the factory in 1991
with a 5.8 liter Ford V-8 and OMC Cobra outdrive. The Y pipe
developed a big hole and I was obliged to remove the engine to replace
it. Now that the engine is out, I am seriously considering
replacement with a small diesel like the Yanmar 2GM20C. I do not need
a boat that planes as I have a smaller boat that does everything I
want for skiing and fishing etc. Also, the fuel consumption of the
Ford V-8 is very intimidating. I would be happier with a little
Trawler-like boat for gunkholing and weekend cruising. First question
is whether a 20-25 hp diesel would mate up well with my Cobra drive?
Can I use the existing Cobra cooling pickups and the Cobra gear
shifting mechanism? Can I feed the diesel exhaust back out the Y pipe
of the Cobra/Ford system? Is there maybe a better way to go to make
my cruiser into a less macho and more homey platform? All ideas and
opinions are welcome and appreciated.

Wayne

In article ,
(wgsant) wrote:

I have a 26' Renken Classic cruiser that came from the factory in 1991
with a 5.8 liter Ford V-8 and OMC Cobra outdrive. The Y pipe
developed a big hole and I was obliged to remove the engine to replace
it. Now that the engine is out, I am seriously considering
replacement with a small diesel like the Yanmar 2GM20C. I do not need
a boat that planes as I have a smaller boat that does everything I
want for skiing and fishing etc. Also, the fuel consumption of the
Ford V-8 is very intimidating. I would be happier with a little
Trawler-like boat for gunkholing and weekend cruising. First question
is whether a 20-25 hp diesel would mate up well with my Cobra drive?
Can I use the existing Cobra cooling pickups and the Cobra gear
shifting mechanism? Can I feed the diesel exhaust back out the Y pipe
of the Cobra/Ford system? Is there maybe a better way to go to make
my cruiser into a less macho and more homey platform? All ideas and
opinions are welcome and appreciated.

Wayne

I think you'll find it would be better and cheaper to put the V8 back in
and run at displacement speed. You'd have to replace pretty much
everything including the fuel tank(s), engine bed, prop, shaft....

--
Jere Lull
Xan-a-Deux ('73 Tanzer 28 #4 out of Tolchester, MD)
Xan's Pages: http://members.dca.net/jerelull/X-Main.html
Our BVI FAQs (290+ pics) http://homepage.mac.com/jerelull/BVI/

In article ,
(wgsant) wrote:

I have a 26' Renken Classic cruiser that came from the factory in 1991
with a 5.8 liter Ford V-8 and OMC Cobra outdrive. The Y pipe
developed a big hole and I was obliged to remove the engine to replace
it. Now that the engine is out, I am seriously considering
replacement with a small diesel like the Yanmar 2GM20C. I do not need
a boat that planes as I have a smaller boat that does everything I
want for skiing and fishing etc. Also, the fuel consumption of the
Ford V-8 is very intimidating. I would be happier with a little
Trawler-like boat for gunkholing and weekend cruising. First question
is whether a 20-25 hp diesel would mate up well with my Cobra drive?
Can I use the existing Cobra cooling pickups and the Cobra gear
shifting mechanism? Can I feed the diesel exhaust back out the Y pipe
of the Cobra/Ford system? Is there maybe a better way to go to make
my cruiser into a less macho and more homey platform? All ideas and
opinions are welcome and appreciated.

Wayne

I think you'll find it would be better and cheaper to put the V8 back in
and run at displacement speed. You'd have to replace pretty much
everything including the fuel tank(s), engine bed, prop, shaft....

--
Jere Lull
Xan-a-Deux ('73 Tanzer 28 #4 out of Tolchester, MD)
Xan's Pages: http://members.dca.net/jerelull/X-Main.html
Our BVI FAQs (290+ pics) http://homepage.mac.com/jerelull/BVI/

Thanks for the comments.

Wayne

Thanks for the comments.

Wayne

I have a boat like that with a similar powertrain. I get 1.3 nautical
mpg at best on plane (20 knots) and 2.3 nmpg at best at hull speed (6
knots). I use this boat 150 to 200 hours a year (mostly at 6 knots) and
buy a bit of gasoline. If/when I repower, I will probably go back to gas
because the motor is so much cheaper, it will bolt right on without any
modifications, it's quieter and I can buy a lot of gas for the
difference in price. ($10,000)

One issue for me is range, which would be better with the diesel, but I
have an auxiliary tank.

Capt. Jeff

I have a boat like that with a similar powertrain. I get 1.3 nautical
mpg at best on plane (20 knots) and 2.3 nmpg at best at hull speed (6
knots). I use this boat 150 to 200 hours a year (mostly at 6 knots) and
buy a bit of gasoline. If/when I repower, I will probably go back to gas
because the motor is so much cheaper, it will bolt right on without any
modifications, it's quieter and I can buy a lot of gas for the
difference in price. ($10,000)

One issue for me is range, which would be better with the diesel, but I
have an auxiliary tank.

Capt. Jeff

"bowgus" wrote in message
t.cable.rogers.com...
Something I read awhile back ... dunno if it's true ... due to the way a
diesel fires as compared to a gas engine, it would hammer your OMC
(designed
for a gas) apart ... ???

It was in response to my (exact) question that wgsant asked. It turned out
that the torque of the diesel during shifting would eventually destroy the
gear sets. When you shift the computer kills one side of the engine to
reduce the torque and allow the gears to engage easily. It would be
imposable to cause the diesel to momentarily stall during shifting. So yes
you can install the diesel but it would kill the drive relatively fast. In
my case I chose to build a little cash and go with the Mercruiser Diesel
Sterndrive. They are a little expensive but should be a nice upgrade.
Besides getting parts for the OMC will be come a issue and since the new
owners of OMC (Bombardier) are known for poor quality products, it makes
sense not to stick with the OMC if it is time to replace the hardware. I
caught up with a guy in Mexico that had a set of diesel Merc's in his ferry
and he said they have not been a problem.

good luck,
mark

http://www.cmdmarine.com/recreationalsterndrives.html