motor selection

[Fr. Frank]

Tim is right on here.
Only try to run back on plane with twin 150's if you have a prop to get it on plane. Otherwise, enjoy the nice smooth rife back to the dock.

I do know a 23'CC with twin 150's that would plane on a single 150, but it was done with 16" pitch props, not 21" or 23" props, AND large tabs. It was a tow boat and propped for pulling.

On the other hand twin 250 Etecs should be adequate

My 2 cents? Big single with an 8-16 hp high thrust kicker.

[Briguy]

Marm, To answer your question. Twin 150's would be too heavy for your boat. That's almost 1000lbs hanging off your transom. Even with a bracket my twin 115 Suzi's come in at 850lbs.

The 250 would handle your needs fine and provide a 25-30mph cruise and pleanty of get up and go.

That being said I believe a 300hp Suzuki would get BETTER gas mileage and cost less. Get a quote.

[KenB]

Hey Marm,

I am on the verge of starting my 23cc project. I am leaning towards twins. I would really like to get a pair of used DF 140s, but HPDIs would be great too. I did look at a pair of old honda 150s last year that bigshrimp pointed me towards, but they were heavy. (And my boat was years away from ready!).

My feeling is that if I buy used power, I will get twins. If I buy new I will get a single screw, probably a DF250. That suzi 300 is a great engine, but it's expensive. Also, I want to see if those electronic controls last for more than a few seasons (in the hands of regular users) before committing to them. The honda 225 is a great fit for a 23 too. My feeling is that all the 225-250's are about the right size for a 23. I have read all the arguments about twins versus a big single, and I agree a new big single is the best way to go. Definitely close the transom and put a huge bracket on either way.

Who knows though. Maybe by the time I finish my build (in a decade), there will be a diesel outboard with variable gearing, and I will just buy a few of those. One of the big knocks on the 4 strokes (heard this in a Japanese commercial fishing boat yard) is that although 4 strokes are car engines, in cars they come with transmissions that allow them to spend most of their time running in the optimal torque/power range. I know nissan has build a car transmission with belts and cones, that doesn't have any gears, which would be neat to see in an outboard. Maybe you could plane a 23 with a geared 90hp? I also know that there are a new set of small block diesels coming out right now with lots of fancy electronics. Anyway, I will probably end up with some light weight twins. That DF140 is a beast and my favorite engine of all time. Just need to find a lightly used, counter rotating, 30" pair.


--
best,
Ken

[Fr. Frank]

Both Mercury and Bombardier now make 200-225 hp two-stroke diesel outboards for military and law enforcement use. Both companies say their motor will run multi-fuel, but only the Evinrude will also burn gasoline. Mercury plans to bring their multi-fuel engine to the commercial market in 2012, in 90 hp, 150 hp, and 225 hp versions. They will run on Jet A, JP5, JP8, #1 or #2 diesel, or aviation-grade kerosene. The recommended fuel will be JP5 or JP8. Running diesel or kerosene will require anti-abrasive fuel additives for permanent or long-term use. Here's an interesting point, both Mercury and Evinrude say you can safely change fuels without draining existing fuel from the tank. With a computer, you simply program the engine to run whatever fuel you're using, in whatever approximate mixture. It can even be reprogrammed with a PDA, using a USB cable.

According to my cousin, who is an engineer for Mercury Marine's sterndrive systems, Mercury is also testing a 400 hp two-stroke V8 diesel outboard powerhead, but that is very early stages. Early complete prototypes are said to be right at 950 to 1000 lbs.

[KenB]

[censored] A, that's awesome. I bet it would do fine with B20 or WVO veggie oil too...

Any performance numbers on those guys? I can't imagine that a diesel powered 2 stroke would have an chance of passing the clean-air guidelines. I wonder if it has an oil reservoir...

Now if we can just get that nissan variable gear transmission saltwater proofed.

[Fr. Frank]

...I can't imagine that a diesel powered 2 stroke would have an chance of passing the clean-air guidelines.

They are all CARB compliant.

[Blackfin26]

Great thread with cool info..KenB, could you provide any more info/details on the small block diesels you mentioned coming out?? Thanks

[zach]

I would highly recommend looking into the small block DI 2 strokes. E tec makes a 200 small block and Merc has a 175 Pro XS. Both would be more than adequate for the power you're going to need to haul loads and they don't weigh nearly as much as the F150. You're looking at weight savings of appx 150-200 lbs. Throw a floatation bracket on the stern and you've got a match made in heaven. I'd be willing to bet you'd easily be able to get on a plane with one engine as well.

I just had a 20 rebuilt but was close to having a 23 redone. If I was redoing a 23, I'd drop two Opti Pro XS 175s on the bracket and be done with it. DIs are the efficient, powerful package that either the E tec or Opti will give you.

[KenB]

Great thread with cool info..KenB, could you provide any more info/details on the small block diesels you mentioned coming out?? Thanks

Hey Blalckfin.

What meant was that 1 out of every 2 cars sold in europe these days is a diesel or turbo diesel. The "car sized" diesel engine blocks were what I was referring to.

Japan basically decided that there was no way to make clean burning diesels and in the 1990's basically outlawed diesels in consumer cars and SUVs. (My uncle had to get rid of his diesel 4 runner.) With hybrid transmissions and commonrail technology, it sounds like clean diesel may actually work. I think I saw a nissan SUV with diesel recently, and I know there is diesel Tundra on the way. I bet a small block diesel in a prius could approach 100 mpg.

And the MEG looks sweet. 30K is a lot for an engine, but if you can burn mcd's fry oil in it, I am all for it.

[NoBones]

Not to rain on the parade..

Until the price of Diesel gets below Gas,
(If it ever happens)
I will stick with Gas for my outboards.

See ya, Ken