Diesel into a ski boat?

[Vaughn MacKenzie]

I've got a typical ski boat inboard/outboard OMC power with 4. 3L GM V6. I am wondering if there is anything out there that would not be any heavier than the 4. 3 and about the same power if possible. Any idea what the 3. 9L B series weighs? Maybe a small MB 6-cylinder? I know any transplant probably wouldn't be easy or cheap, but it's fun to ponder the idea



Vaughn

 

[bighammer]

I've often pondered replacing my 350 Mercruiser with a Cummins 5. 9 Probably not worthe the time, money, or trouble.



(but maybe someday when I have an extra engine and too much time on my hands... . )

 

[JWhitcomb]

Well it sure would cut down the chance of a fuel explosion.

 

[Vaughn MacKenzie]

Originally posted by bighammer

I've often pondered replacing my 350 Mercruiser with a Cummins 5. 9 Probably not worthe the time, money, or trouble.



(but maybe someday when I have an extra engine and too much time on my hands... . )

I thought of that, but figured it might sink the boat. If I kept moving though I might be OK



Vaughn

 

[therabbittree]

what power does your v6 make? vw makes tdi engines for industrial and marine versions. . also you could scrounge a auto version. . they have inline 5cyl 2. 5L's and v6 versions and i believe a inline 6 too that would be really light and make some power. . izuzu and nissan inline 6cyl are good too but i think they are heavier... any how hope thathelps. .

later

Deo

\x/ hillfolk!

 

[Vaughn MacKenzie]

The current V6 is rated at 175 and moves the boat along very well. I figure with the added torque of a diesel, I could do well with 150hp because the torque would help get me out of the hole with a skier.



The skiers would have to not mind a little diesel smoke in their face as they're pulling up

 

[tk064]

Some of the new fishing boats have a 3. something cummins in them that is sold through mercrusier I believe. It is as a replacement for the 3. 3 liter?? or the 150hp outboard.



The reviews on it are very favorable. It is allegedly quieter and smoother than booth gas motors. I think it is 120 hp.

 

[soslow91]

Cummins lists the weights of their marine engines and alot of websites show this info if I remember correctly the 3. 9 is a little over 700# the 4. 3 is probably low to mid 400's i think the 350 weighs 550 or so and a 3. 8 buick 375 so thats a rough guess yes the chevy weighs more than the buick.



The torque of the diesel could be a little high for the outdrive I really wouldn't know but even a rotary pump 4bt should be able to get 250hp especially with a freshwater intercooler.



With the lower engine speed of the diesel a more agressive prop would be needed to get the same top speed which means you needs more torque off the line so the fastest spooling turbo you can get is probably the way to go an hy35w9cm2 from a newer truck would probably work especially if you don't want high hp.



anyway enough rambling from me as always have fun

 

[GWHaley]

check popular mechanics

In one of the last issues of Popular Mechanics, they had a test that consisted of trying three different engines in the same hull. One was a I4 gas, one V6 outboard and one Cummins diesel (inline four, turbo). All the engines had similar H. P. ratings. The results were pretty amazing with the diesel getting double the range on fuel and not really suffering that much on performance or cost. Interesting read, check www.popularmechanics.com Go to Outdoors, boating and it's at the bottom of current articles.

 

[mberry]

Originally posted by tk064

Some of the new fishing boats have a 3. something cummins in them that is sold through mercrusier I believe. It is as a replacement for the 3. 3 liter?? or the 150hp outboard.



The reviews on it are very favorable. It is allegedly quieter and smoother than booth gas motors. I think it is 120 hp.

The 3. 0 liter diesel sold through Mercruiser is built by Isuzu, not Cummins. It is rated at 120Hp.



However, Mercruiser is teaming with Cummins to built a line of diesel powered sterndrives. When I get more info I will let you all know. I am considering repowering an old cruiser with a B series engine also.

 

[stacerbob]

I have a 22' Mastercraft that I use for wakeboarding. When I had that other 12v laying around it was awful tempting. When wakeboarding you only cruise about 22-28MPH depending on the rider so top speed is not an issue. People are always tring to add more weight to make the wake bigger so there is another plus. I just wonder about the strength of the mounts to hold that bad boy in place!! My final desicion was that I do not LOVE this boat and if I did the conversion I would probably be stuck with it. It is not one of the "desireble" mastercrafts as it has the swim deck made in to the rear so it is really just a 19. 5' boat but it is 22' long!!

Do it and keep us posted!! What about the 3. 4 cummins 6cyl??

 

[JLEONARD]

Yanmar makes a 4 cylinder diesel that they advertise as a direct replacement for a Chevy 350. They are available up to 230 hp I believe.

My marina neighbor installed these (rated at 170 hp) in his twin engine boat and they do fit in the same space as his 350s.

He lost about 2 knots of cruising speed but gained a whole bunch in terms of economy and range.

I repowered my boat 3 years ago with a Cummins B series rated at 270 hp... I replaced an anemic old Perkins t6. 354.

Jay

 

[LightmanE300]

GWHaley, as per the article in popular mechanics, that diesel sounds like a good choice in that boat. None of the boats are particularly quick, and the diesel has great economy!

 

[catoiler]

Now this if interesting..

Just got back from 2 weeks vacation with the boat ,and half way through and a lack of HP to get my fat up on a board,had a thought about a 5. 9 in place of the dang 302. Nice to see I'm not the only deminted one out here!