255 Conquest Re-power

Optimizing the performance of Boston Whaler boats
Littlechucky
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Joined: Sun Jul 16, 2017 10:37 pm

255 Conquest Re-power

Postby Littlechucky » Sun Jul 16, 2017 10:47 pm

Hi all--new forum member. I have a 2005 255 Conquest with a single 300 Verado, The boat is definitely under-powered when running in the any kind of chop or getting up on plane. I carry a decent amount of fishing gear and three or four 200-lbs guys. [Performance is] fine on flat water but really struggles in the slop when you get knocked off plane. Fuel burn is brutal in those conditions.

I am pretty much sold on the new E-TEC G2 and am thinking about a pair of 200-HP engine, but I may have a line on a pair of 200 H.O. engines, which should be almost 440-HP. I think those might almost be too much power with all the low end torque. The maximum power rating on the boat is 450-HP. I've see some CONQUEST 255 boats with twin 200 OptiMax engines.

My primary concern is strong acceleration onto plane from a standing start and fuel efficiency. I am not looking for top end speed with all the logs in the water in the Pacific Northwest.

Appreciate any thoughts.

jimh
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Re: 255 Conquest Re-power

Postby jimh » Sun Jul 16, 2017 11:33 pm

Twin engines are needed, in my thinking, when the boat length is 25-feet or more, and power needs to be over 300-HP. The 255 CONQUEST meets those criteria, and it is probably a heavier boat than many 25-footers due to the cabin, the accommodations, and Boston Whaler Unibond hull construction. On that basis, re-power with twin engine seems quite appropriate.

Of course, going with twin engines won't be cheap, and switching to Evinrude from Mercury will add some more to the cost by requiring substantial re-rigging.

When you mention E-TEC 200 G2, I think you are referring to the smaller displacement model based on the 2.7-liter block, and when you mention the E-TEC 200 H.O. you are referring to the larger displacement model based on the 3.4-liter block.

Since I am spending your money, I'd go with the larger displacement engine. It should give you the ability to get the boat on plane with one engine running and the other out of the water, a nice option to have if there is an engine problem. And you should be able to run the 200 H.O. engines at a nice sweet spot for fuel economy when at cruising speed. The difference in the engine weights is small, about 17-lbs; the 200 is 541-lbs and the 200 H.O. is 558-lbs. I have no idea what the price difference would be.

With any engine re-power, the choice of the dealer who will do the installation and after-sale support is very important--and that goes for any brand. I'd want to work with a dealer who thought of the engines I was buying from him as the principal engine brand he sold. The one he really likes the best and sells the most. And since the Evinrude E-TEC G2 line is relatively new, I'd want the dealer to be completely up to speed on those new models, to have experience with them.

One questions I'd ask: with twin engines should both engines have Dynamic Power Steering (DPS)? Or should only one of them have DPS and the other non-DPS, since it is coupled with a tie-bar to the DPS engine?

I think if you want to get joystick control, you probably need both to have DPS. That's another question for the dealer.

For the rigging, I'd get the ICON II Premium EST controls (not the ICON II Basic controls). And I'd get the ICON 7.0 CTS color touch screen display for instrumentation, perhaps augmented by two ICON Pro RPM gauges (3.5-inch diameter) and one ICON Pro Speedometer gauge just to have engine speed and boat speed displayed on dedicated dial pointer gauges.

I would also want the dealer to have available several sets of propellers for sea trials and testing. I'd want to be able to test both three-blade REBEL propellers and four-blade RX4 propellers, and to be able to test them in at least two or perhaps three pitches. So that means perhaps eight to 12 propeller available for testing.

Now we just have to work out the color scheme--and there are a lot of choices.

Littlechucky
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Joined: Sun Jul 16, 2017 10:37 pm

Re: 255 Conquest Re-power

Postby Littlechucky » Mon Jul 17, 2017 12:09 am

Thanks for that. Yes--considering if the big block 200 H.O. is over-powering the boat. Cost is not much concern. I would rather not be at the fuel dock so often and like the reduced maintenance.

Currently [the 255 CONQUEST with 300 VERADO can] cruise at 25-nautical-miles-per-hour at 4500-RPM, and burn about 15-GPH on flat water. Battling the stacked up chop, I've burned close to 100-gallons only going 80-miles--not kidding.

The boat is 4900-lbs dry. Then add:
--fuel 100 gallons 700-lsb
--crew 600-lbs
--engines 1,100-lbs
--gear 300-lbs
[and the total boat weight is] probably 7,500-lbs most days.

jimh
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Re: 255 Conquest Re-power

Postby jimh » Mon Jul 17, 2017 8:28 am

Before I re-powered with a modern engine, we had the occasion to make way upwind in some big waves to return to port. Running at a slow-plane or almost plowing into the head seas, my Revenge 22 with single 225-HP carburetor two-stroke-power-cycle engine was getting 1-MPG. We were in extreme northern Lake Huron, in Canada, and at that time the fuel we had just bought was over $5-per-gallon. At that price for gasoline and adding in the cost of oil at about $0.65 per gallon of fuel, I was thinking, "Wow, to move this boat is costing almost $6-per-mile." That seemed like an absurd cost for a relatively small single-engine outboard boat. Of course, now I can routinely buy gasoline fuel at under $2-per-gallon (using a fuel discount point method linked to my grocery shopping), so the actual cost of the fuel has dropped enormously. However, I have no regrets about re-powering, and the overall fuel consumption has dropped almost in half.

Jefecinco
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Re: 255 Conquest Re-power

Postby Jefecinco » Mon Jul 17, 2017 8:50 am

If you think 350 HP would be sufficient have a look at the new Suzuki dual propeller outboard engine. A single 350 HP engine with less drag than twins may well accomplish your goals.
Butch

jimh
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Re: 255 Conquest Re-power

Postby jimh » Wed Jul 19, 2017 10:35 am

Regarding the Evinrude E-TEC engines at 200-HP, there are four different engines available in the matrix of large or small block and G2 or legacy models. I go into detail about all the variations in an article at

viewtopic.php?f=7&t=2213

The article is a comprehensive collection of information about the E-TEC G2 and E-TEC legacy engines at 200-HP power.

msirof2001
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Location: Southern California

Re: 255 Conquest Re-power

Postby msirof2001 » Mon Jul 24, 2017 12:27 pm

I won't restate all I said here regarding the 1993-1997 OUTRAGE 24: viewtopic.php?f=7&t=2396

Looking at your mileage needs, with less concern for speed, the twin Yamaha F200 XB setup may be worth considering. The OUTRAGE 24 with twin Yamaha F200 XB stacks up like this:

--boat 3,300
--engines 486 x 2=972
--fuel 195 x 6.2=1,209
--bait 35 x 8 = 280

And that adds up to 5,761-lbs. Then you add batteries, gear, emergency equipment, water, people and donuts. I don't think you'll hit the 7,500 lbs you're describing but I don't think there will be too huge a gap.

I don't think you'll hit the 50-MPH the OC Sheriff stated. They have a 125-gallon fuel tank so that's 434-lbs less, but I'm sure they make up for it a little with emergency equipment. Trying to make this somewhat apples-to-apples.

I just think the twin F200 XB is worth contemplating amongst other setups. A lot also has to do with the available servicers. I am in Newport Beach, California, and West Coast Marine Service (WCMS) is a Yamaha 5-star Gold operation and is noted throughout Southern California for excellent service. I have Yamaha engines and I'm extremely happy. Yamaha in Newport Beach is like American Airlines in Dallas (DFW Airport).

In Oxnard, CA Specialty Marine is to Honda what WCMS is to Yamaha. Oxnard is 104 miles away from Newport. If I were based in Oxnard, I would have gone Honda.

The current, modern engines are all outstanding. Not homogeneous but in many respects very close. The quality and proximity of great service was material to my decision.
Current: 2017 Everglades 295cc, Previous1: 1995 Boston Whaler Outrage 21, Previous2: 1974 Sevylor Caravelle 3-man liferaft.