diesel outboards

[Rory Renwick]

Is there anyone out there who knows of a diesel outboard of more than 100hp. We are working in an area where it is very difficuilt to get significant amounts of any fuel other than diesel

Thanks R

[marshmat]

I am aware of only two diesel outboards; both Yanmars, both much smaller than you are looking at. The diesel's traditionally high weight has so far made it unsuitable for outboards. If you can only buy diesel, you'll probably need to go for inboard or sterndrive.

[Johnhink]

Some time ago, I read about the use of the GM 6-71 diesel in use with an out drive which was mounted on a barge. It may be that a 4-71 could be used in the same circumstances.

[ron17571]

I looked at the ads for those outboards,very heavy and very expensive!I dont know what your trying to power,but with diesels u should think about torque not so much about horsepower,i am coming at this from a truckers view,mabe someone more knowledgable wants to chime in.I read a site that used a modified volkswagon diesel engine,seemed like a cheap way to go.I keep reading and looking for creative ways to produce power reliably and cheaply!Seems like many sites and posts are from the rich n famous trying to impress others.good luck!

[Johnhink]

As I recollect, I was responding to a query concerning diesel outboard engines in excess of 100 hp.
I agree the engines are very heavy. The boat must be able to support both the weight and the vibrations.
The point I think I was trying to make is; Detroit diesels that are two stroke cycle, are much lighter in weight than are the four stroke cycle and the 53 series is much more economical than are the 71 series. The life of either is dependant on the maintenance they get and how well they are maintained.
There are some discussions concerning the operating economics of these engines as opposed to the other popular four stroke designs (GPH fuel).
However, the sight of a large 8V71 attached to an outdrive to move a barge was something that is not often seen.
The use of smaller four stroke diesel engines to power hydraulic drives are not uncommon and might be considered, as well. A single engine mounted inboard can easily operate two hydraulic propulsion pumps.

[Fr. Frank]

Bombardier/Evinrude makes a 200 hp eTec called the eTec MFE, for multi-fuel engine. It will run on diesel, JP4, JP5, JP8, #1 kerosene, or unleaded 87 octane gasoline, and can change from one fuel to another just by turning the fuel selector switch. It is currently available only to the US Military. The eTec MFE is also available in 35, 65, and 90 hp versions.

Mercury has two engines, a 200 hp 500 lb. multi-fuel version of the Optimax, which will burn all of the above except gasoline and is also designed for the Navy, and a 400 hp, 380 lb turbine outboard developed in partnership with MTT, which is still in testing, using a Rolls/Allison series 250 turbine.

[Jimbo1490]

using a Rolls/Allison series 250 turbine.

Love that little engine! I bought one from a surplus auction back in '94 for a whopping $1200. It was pulled for low oil pressure in the gearbox. My buddy from Airwork help me tear down the box. The problem turned out to be jus a torn O-ring about 1/4" diameter. It ran perfectly, had only 200 Hrs TSO, and was the 420 HP (C20 civil) version.

I was going to put it into a Fiero; had all the details worked out, plans drawn up, etc. But a very nice offer for the engine came along and that was the end of that An outboard motor was another thing we wanted to try with it. It went to a guy who put it on his airboat.

Sometime I wish I had built a project with it as the $20K is long gone, but the memories of a project would still be with me


Jimbo

[Pericles]

http://www.swordmarine.com/

200 hp diesel Jet Pac

Pericles

[Frosty]

Interesting!!! However as is so often the case not a single picture of the unit without the cover? How it is attached?

Unless this all came in the brochure that I had to down load.

PRICE????? Marketing techniques seem so strange these days.

Remember the old days (---Triumph T100 ---49 pounds 6 shillings and sixpence.)

Its like the price should be of no consiquence !

Frustrating and very very off putting.

[Pericles]

Frosty,

Bolted through transom.

http://www.fleetwatermarine.com/JetP...ion_system.htm

Was on offer in UK for £15K including VAT.

Guillermo can advise you better than me.

http://www.gestenaval.com/jetpac.htm

Regards,

Pericles

[mydauphin]

First, Detroit diesels are great engines.. Mine get 10,000 hrs between rebuild and are 30 years old and work great. but light they are not. A 671 with tranny is 3000lbs and a 871 about 4000lbs. Those outboards for barge are mounted on deck with a z-drive over the side. Works like IPS... Just alot slower, heavier and bigger. So forget making them an outboards.

Those eTec MFE and like outboard will only run on diesel in emergency if mixed with something else like gasoline... 50/50 mix. they used spark plugs and have low compression... not really Diesels engines.

The problem with diesel outboards is torque, a 200hp diesel will put out alot of torque, much more than gas 400hp. The prop and gearing have to made 3 times size to take advantage of it. Therefore diesels are meant for slower crafts running big slow props.

That is why Yanmar 27hp diesel outboard pushes a boat like 40hp but not very fast. Good engine, expensive last I looked $15,000, not allowed in US for pollution control reasons.



Jet Diesels pod get around diesel transmission and torque problem as jet drive absorbs torque and turns it to thrust. Good idea if engine is light enough. I looked at them. Only two problems.. Cost - higher than all solutions and corrosions. Those diesels are Aluminum and are salt water cooled. They wont last long in salt water. Same problem with Yanmar outboards...



For many configurations it is hard to beat a single diesel, straight shaft, dry exhaust, one prop, one rudder... Works everytime

[Frosty]

Again interesting but not one picture of the unit with the cover off. I did find on the second link a line drawing of the engine above the jet, belt driving the lower unit. However the weight of all this is mounted where --on the fibreglass cover???

A very interesting idea that I don t understand. It really annoys me to read material such as the three links I have seen. How it is environmentaly friendly and easy to fit, shallow water capabilities, no propellor ,---damned annoying.

[mydauphin]

I saw them at boat show several years ago.
The compartment is tight. The engines small. The pod provides some floatation so actual weight on transom is like 300lb. They custom make attachment to transom since angle varies.

Thrust is limited by small jet. My concerns where corrosion as mentioned and air being suctioned into jet if there is any wave action. Not meant for ocean going boat. Great for lake boat or bay runner.

They claim environmentally good because diesel model give great mileage compared to typical gas outboard or inboard and this system could be used to mount diesel in small boat. On a small boat like 20' it gets like 6mpg.

I thought idea had merit since I would love boat that engine is in separate pod to boat to allow easy service. I just need it like 10 times bigger....

[Frosty]

Mydauphin --I couldnt agree more. however I would be concerned at the stress on the "pod" taking this wieght in a pounding sea,--- or lake,--still gets rough.

All that weight on a pod??? Now it may be there is some sort of steel frame but its not made that clear has it?

[mydauphin]

Originally Posted by Frosty

All that weight on a pod??? Now it may be there is some sort of steel frame but its not made that clear has it?

Good point, I dont think one should be jumping wakes with this attached on back. It has no steal just fiberglass and maybe some wood stringer. Metal would break thru fiberglass anyway. Like many things, good for somethings not for others. But at $21k for diesel version, I cant cost justify it.