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After talking to several mechanics that repower boats, I am confused about my options for repowering a straight inboard B25. The boat in question currently has 318 Chryslers in it. For the record, can I replace those engines with diesel? If so, which ones? If not, what are my other options?

Will diesels be too loud in the cockpit?

Davidms

I had that set up with 360s &Vee drives... I dont think the drives can take a diesel!
But I read recently a 25 will take a 6bta cummins single.
Good luck & keep us posted;
Wayne

david....is it straight shaft or v drives?......

David.
If your looking for something that is a direct drop in with little to no modifications it ain't gonna happen.

Diesels do fit in a 25. But its gonna take some engineering and planning and quite a bit of work.

Its not a project that a novice should tackle.

Go over to the 25 board and look around.

There are all kinds of power opotions that have been tried in that hull and you will proabaly find a proponent of each possibility there to tell you why their idea is the best.

Here is a link:

http://simplifying.net/phpbb/index.php

Peter

Randall,

There are V drives in the boat currently. Suggestions on engines?

Bruce,

I spoke with a guy who put small Yanmars in his 25. He didn't mention any modifications but did say that the diesels are kind of loud. What modifications do you think he made?

To all,

I am biased toward figuring out a way to repower with diesels. Is there anybody who can convince me to replace the gas engines with gas engines?

Davidms

david...might want to look at these....i have......its all about the$$$$


http://www.crusaderengines.com/NewFiles/5057specs.pdf


for what its worth....my 25 has 1984 chrysler 360's and id be happy with them for as long as they run..(true 40 MPH boat).....

David,
Mine's got Marine Power 350's (carbureted) in it. I replaced the original Paragon transmissions and v-drives in 2000 with Walter v-drives and Velvet Drive transmissions. In 2003 I dropped the Marine Power engines in. Cruises at 2900 rpm at 24 mph while burning around 14 gph with a heavy load. Hope this helps.

-Kel

Volvo D3s...

http://www.volvo.com/volvopenta/na/en-u ... d3-160.htm

Ian.

The endless debate....problem is that no one answer is better than another. Bottom line is do what you want to do. Can we get some onfo from the guy that put the small Yanmars in the 25? performance, pictures, etc.

Not being one given to common sense and taking the easiest, best route...I'll render only this opinion on repowering a 25:

>if you go diesel, anything over 250hp (total) should work.
>If diesel, anything over 325-350hp is a waste.
>keep the total engine weight under 2,500lbs
>Keep the engine weight aft of the hulls COB (10ft forward of the stern cap)
> Last but not least, do your homework....and know how much work you can do at home.

Bruce's advice is real good here, do you have deep pockets or can you grind and glue for 3 years?

Good Luck.

I know that boats are holes in the water that you keep throwing money into. BUT...

if money wasn't an issue, would you make the modifications that Bruce mentioned to fit a pair of diesels into a 25? Or would you convert to a single diesel? Or would to repower with new gas engines? Remember that this is a straight inboard w/Vdrives.

I am trying to figure out what the best choice is and see if I can get there given my budget.

Thanks for the responses.

Davidms

David: Go look at Scot's website. http://www.cssims.com/

This is a pretty common discussion on the 25 board. I think alot of the guys who are biased to diesels (as opposed to the outboard fans) would seriously consider a single diesel, althogh twin Volvo D3 160s or 190s have also been installed with great success. Given that you have a v-drive boat a couple of small diesels running new v-drives with beefed up shafts would be fantastic as well.

I tried to replace my 1-1/8" shafts with 1-1/4", and I discovered that the existing hole drilled in the hull wouldn't allow for the increased diameter. The 1-1/4" shaft would go through the hole, but alignment would've been impossible. Of course, if you're going back with diesels, there's a whole lot of other things you'll be doing to the boat that will probably make redrilling the shaft hole a minor issue.

-Kel