92 series Detroit Diesels

well thank you once againe kind sir...You have convinced me . I will forget that idea.. I feel better already....I am hoping that nothing over 1900 rpm , frequent fluid changes etc I will be fine. Thats my plan anyway. I can live with the black smoke from my stbd side when quick on the stick....She alittle knocky as well....

If it puts out a bit of black smoke on acceleration and runs out clean, it may just be the throttle delay.
A crude device that some times works . Or just ease up the pins slowly.

If you have black smoke while running, I would recommend old DDC tech to get involved .

Question, those throttle delays, I had a father/son mechanic team at my rebuild, the son removed them, the father put them back... what's your opinion Ralph?

Thanks Ralph......Stbd Betty buffs some black with a quick stick , running at speed they both just seem to be blowing steam. My transome does soot up in time , I run 1850 and seldom above or below...

How are your air and fuel filters?

I removed them from my 12V71TIs. When cold, the throttle delay kept the racks stiff and the engine would hunt for idle.
I have the newer control tubes also, with springs keeping a locked-up injector from binding the rod.
The throttle delay on the 71s is still the original design. There is no safety springs on the rod arm.

I can punch my 71 and make black smoke, but normal operation, I slowly advance the throttles and no problems. This is the only reason for them; reduce acceleration smoke.

I have never heard of one locking up the control rod but it is easily possible when you look at it..
It's something else to fail and disable your engine.

The throttle delay will not have any smoking effect on a good running engine. When climbing swells I have no smoke. Others trash their transom and blame the throttle delay in-correctly. Their just not running rite.

If I read well, you would remove them as this could be a potentional failure item?

I have the new racks also, and 'easy going' on the throttle!

I have never witnessed a failure.
I heard of one. That may have been an installation issue.

I would not go after them just to do so, but the next time the covers are off you may consider it then.
Scribe the angle position and take some pictures, if you want to put them back on later.
Un-fasten the arm from the control rod and pull the piston from the cup. Don't drop the U bolt nuts into the head. That's it.
There is a tiny square head screw next to the cup that you are leaving on the head (valve cover bolt screws into the assembly). This is the factory set oil flow adjustment to the cup. Your not going to loos any oil pressure, I don't remember any spec or adjustment also. I left mine alone since so little oil flows into the cup.

It's not a big woo and if your running good,, remember one thing,, never kick a sleeping dawg.

Thnx Ralph, I have 4 dogs, so I know...

I am hoping can hear more praise for the 92s ,i am looking at two bertrams 46 Cs ,one with the 92s one with the 71s ,i am leaning towards the one with the 92s because im familiar with boat and know how was used so any opinions i would appreciate ,hopefully some more encouraging ones for the 92s . Thanks

71's are the standard..believe it..

71's rule.

Lots of 92's out there (although not nearly as many as the 71's given length of time they were produced). I got nearly 4,000 hours and over 20 years out of my 92's before they needed MOH. I think the 92's are like anything else, it depends on how you treat them and maintain them. Also really depends on what your priorities are. I'm guessing the hulls with 71's are older vs. the one's with 92's. Is speed a factor for you? What are the different fuel burn rates vs. speed? Have either of the boats you are looking at had MOH's?

In all of my experience, I've found that once the 92's got a few hundred hours on them, they'd lose 10-20% of their HP somewhere (not make top rpm was a common problem with them.) After that, they seemed to be hardly any faster than the 71's in the same boat. I mean like 1 knot faster, maybe 2 knots...... but nothing worth the fuel burn and hassles and much shorter lifespan. That being said, when buying a used boat, they have what they have.

I can only speak to the experience with the 92's in my boat. I've never had a problem reaching 2,350 RPM. Even right before time to MOH I would still get to full rpm if desired or needed and that was with nearly 4k hours on it. Perhaps folks are propping to close to max when boats are new to squeeze every knot out of them and as they grow weight, bottom fouls, etc RPM's are lost??

In my last boat the 92's were fantastic.

Definately. Most builders do that. But also most owners add thousands of pounds of crap to the boat, the bottom gets heavier with 20 coats of bottom paint over the years, and on and on.

Capt J could you give me a rough estimate for fuel cost to run a Bertram 46 from CT. new haven area to say Myrtle B each area ?

I would travel at the most efficient speed ,trying to figure out what that trip would cost.

About 1000 rpm, no more than 1100 rpm ...about 8.5 - 9.0 knots is your best travel speed/fuel consumption in a 46' Bertram w/DD8v92's. You're going to burn about 1.33 gals per mile excluding generator. And that's if you're up to spec on injectors, and props, clean bottom, good weather, all that stuff. 750 miles x 1.4 = 1050 gallons plus 75 gallons for generator. I always round up. Approx 1125 gallons. That's close enough to give you an idea... I assume you're going to come inside at The Chesapeake to Norfolk and run down the ICW from there. So, you'll spend some time at even lower speeds.

If you run even slightly faster, like around 1200 or above ...you will barely gain a knot and burn waaaay more fuel.