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Author Topic:   1999 CONQUEST 28; OptiMax v EFI
BIG O posted 04-10-2007 07:01 AM ET (US)   Profile for BIG O   Send Email to BIG O  
'Morning. I was wondering if anyone out there may have [a 1999 CONQUEST 28] and would share some information. I had a 1999 Outrage 26 which I sold and have my eye on [a 1999 CONQUEST 28]. Looking over the specifications I am a little surprised the weight of a [1999 CONQUEST 28] is 5,600-lbs. The weight on the new 2007 [285 CONQUEST] is 7,500-lbs even though the length overall is the same, the 2007 has a narrower beam, 9-feet 8-inches as opposed to 10-feet 4-inches. I wonder were the weight difference is.

One other point: my old Boston Whaler 1999 OUTRAGE 26 had a 225-HP OptiMax; this [1999 CONQUEST 28] has 250-HP EFI. What are the differences between an OptiMax and an EFI? Are they not both electronic fuel injection? Is there a difference. Thanks in advance for any information that you can share.

Blackbeard posted 04-10-2007 07:50 AM ET (US)     Profile for Blackbeard  Send Email to Blackbeard     
The Conquest models have been renumbered and re-designated since first being introduced. The boat you are looking at may be what was formerly known as the 275, or even possibly the 2600. The most reliable indicator is probably the fuel tank size (192-gallons for the 275) and the beam of 9-feet 8-inch. The 28 has a 10-foot 4-inch beam and tanks of 296-gallons. The 28 also weighs 8,500-lbs dry. The 5,700 lbs vs. 7,500-lbs you are looking at applied to hull only vs. full rig with hard top, etc. The present 305 is very close in specs to the old 28 and the 285 is really the old 275.
jimh posted 04-10-2007 09:15 AM ET (US)     Profile for jimh  Send Email to jimh     
jimh posted 04-10-2007 09:31 AM ET (US)     Profile for jimh  Send Email to jimh     
There is an enormous difference between a classic two-stroke engine whose fuel system uses a simple electronic fuel injector instead of a carburetor (which Mercury calls "EFI") and the very complex direct-injection engine Mercury calls "OptiMax." They differ in how the fuel is introduced into the cylinder.

The EFI design is basically the same as all two-stroke motors made since the beginning of outboards, it just replaced the carburetors with one or more fuel injectors. The OptiMax is a direct-injection two-stroke which has an air compressor, air injectors, fuel injectors, and a relatively complicated assembly of fuel rails, air pressure rails, hoses, pumps, etc. The reason for all the extras was primarily to meet EPA limits on exhaust emission. The added bonus is much better fuel economy at low speeds, and better fuel economy at cruise.

In a nutshell, the EFI is probably considered "reliable" and the "OptiMax" is considered "runs great when it works right". There are many prior discussions about the OptiMax. You should use them as background reading, and form your own opinions.

BIG O posted 04-10-2007 10:56 AM ET (US)     Profile for BIG O  Send Email to BIG O     

Thanks to both of you foryour response, the Conquest has a 296 capacity fuel tank. I am planing to go take a look at her over the weekend.
Best Regards
Blackbeard posted 04-11-2007 08:25 AM ET (US)     Profile for Blackbeard  Send Email to Blackbeard     
Good luck. Let me know if you have questions. If you take it out for a trial pay close attention to fuel consumption. It is a heavy boat and the fuel efficiency of a two stroke may matter to you. You can do some research and may conclude you don't want to pay too much for the engines. Also, spend some time on docking/maneuvering (particularly in reverse). The engines may be mounted closer to each other than optimal and make maneuvering a little more demanding. I have an '01 28 that I just repowered with Yamaha 4 strokes.
handn posted 04-16-2007 09:30 AM ET (US)     Profile for handn  Send Email to handn     
A friend has Merc efi 225 two strokes on a 28 Conquest. The engines are gas guzzlers. Fuel consumption is almost double what my YamaMerc 225 efi four strokes burn on a 305 Conquest.
I would pay more for a boat with more economical engines or if the boat you are considering is cheap, factor the additional fuel costs into your decision of whether to purchase.
dr john posted 04-16-2007 09:05 PM ET (US)     Profile for dr john  Send Email to dr john     
I have a 2002 290 outrage with optimax 225's and burn 10-12 gph at 4000-4500rpm. What kind of fuel burn are the 4 strokes getting?
handn posted 04-16-2007 11:35 PM ET (US)     Profile for handn  Send Email to handn     
I don't have smart craft gauges or flow scan meter so it is hard to say exactly what I am burning at 4000 rpm. I keep overall fuel economy records and get 1.3 nautical miles per gallon between trolling and cruising on my 305 Conquest.
I went on a cruise with a friend who had a 28 Conquest and Merc efi 225 two strokes. We went 120 nautical miles. I burned 92 gallons of gas and he burned 160 traveling at the same speeds.
My prior boat, a 23 Conquest had a single 225 Optimax. It was economical. I think fuel consumption is very comparable between the two engines.
dhlaw posted 04-17-2007 07:26 AM ET (US)     Profile for dhlaw  Send Email to dhlaw     
Let me tell you, thios e EFI motors will put you in the poor house with fuel burn!! When I first got my new boat in 2001 with Merc 225 EFI's I thoughth it had a fuel leak... thats how bad the mileage was. Optis get fantastic mileage and can be trouble free. I have over 400 hours on my 2000's with only a few small issues that were addressed under warranty.
Blackbeard posted 04-17-2007 08:18 AM ET (US)     Profile for Blackbeard  Send Email to Blackbeard     
Picked up the 28 Conquest with the Yamaha four-stroke 225-HP re-powers last week. The old engines were Yamaha Saltwater Series OX 66's 250-HP--Bullet proof engines in so many ways. Did not take it for for more than a check ride and back to the dock but did make some quick observations. Not as quick out of the hole, but nothing I won't get used to - the torque just isn't there. But, once up on plane maybe more power. I was light on fuel so maybe weighted 9,500-lbs all in and at 4,300 [RPM] I was buring a combined 21-GPH and making 32-MPH in a moderate bay chop into the wind of 10-knot. With the two-stroke motors this would have been 28-GPH PLUS oil. At WOT 6,000-RPM the engines were drinking 26-GPH and I was making 43-MPH.

I'm looking forward to full trials (and justifying to myself the extraodinary expense of the repower) and will post them later. The two-strokes were a killer on gas and oil and range was severely restricted. Making the inlet on fumes after a canyon run gets you to thinking.

Brian7son posted 04-24-2007 04:18 PM ET (US)     Profile for Brian7son  Send Email to Brian7son     

when you said: "Picked up the 28 Conquest......did make some quick observations. Not as quick out of the hole, but nothing I won't get used to - the torque just isn't there. ....... I was light on fuel" you got my attention.

Your rig sounds similar to mine. I have a 1998 285 Conquest with 225 Merc. 4 strokes. On 11/03, before I purchased my boat (2/06), the hull was replaced by BW under warranty due to factory recall. When you said that the rig was "not quick out of the hole AND light on gas"
I was wondering how it performs with a full tank. Mine gets up on plane fine with 1/2 tank of gas or less, but I wouldnt ever call it "quick out of the hole". It's the full load hole shot that I have issues with.

You also seem to know the specs on these rigs: "The 28 has a 10-foot 4-inch beam and tanks of 296-gallons. The 28 also weighs 8,500-lbs dry." That is my rig. Did they cut the fuel capacity and lighten the hull in later models because of possible performance issues (hole shot, etc) with so much weight?

Thanks for any information that you can provide.


Blackbeard posted 04-25-2007 05:21 PM ET (US)     Profile for Blackbeard  Send Email to Blackbeard     
I don't know why BW went through the hull revisions beginning in late 2001 I do know the "BW design bureau" underwent some personnel changes with the Rebok to Brunswick sale. The stepped Conquest hull (similar to a braket type arrangement) has been abandoned in favor of a more conventional hull/engine formation. I don't know the engineering behind the decision, but I can imagine that the newer and more conventional setup has some benefits over the stepped hull. For example, the stepped hull in reverse (particularly close in manuvering) is not as effortless as other designs (but then again, have you ever docked a round bottom hull with a single screw inboard with the current running from 2 o'clock and 15 knot breeze from 10 o'clock?). I'll fill my tanks in the next two weeks and try out the 4 strokes to see if I can duplicate your issue. Prior to this season, I ran 250 HP OX 66's and never had any issue getting out of the hole/up on plane with a full fuel load and several passengers - lots of weight. Always up on plane by 3600 to 3800 RPMs. The OX 66's had tons of torque and the bite was sure. I know I'll loose some of that bite with the 4 strokes and I may push up to 4000 with a full load.
Brian7son posted 05-02-2007 05:02 PM ET (US)     Profile for Brian7son  Send Email to Brian7son     

I hope that you cannot duplicate my problem in your boat. I certainly would not wish that headache upon you. I know that the prior owner of my boat also had older 250hp, 2 stroke engines. He advised me that he had switched to the 4 stroke Mercury for better fuel economy. I certainly have no fuel economy problem on the rig. I did notice that when I look for info. on the 225 Merc. 4 strokes, that they stopped making them. Mine are 2004's. Now it's either optimax or Verado, but not my engine. Maybe it's just the way the setup was done on my particular boat, placement of generator, etc. I dont know. I really think it's just underpowered.

Good luck with your repower. I cant justify spenging that kind of coin right now. I'd really love to see how my rig would get up with a pair of 250 E-tec's. It would be about 130-140lbs (combined) lighter in the stern.


Blackbeard posted 05-07-2007 08:16 AM ET (US)     Profile for Blackbeard  Send Email to Blackbeard     

Fueled up this weekend and ran some trials on the new engines (Yamaha 4 strokes - 225hp). Three adults on board (170 lbs each), full tanks (296 gal), 40 gal of domestic water, full enclosure, outriggers, no gen set. A running start from 2 K rpm with the wind and current took 18 seconds and 4.2 K rpm to plane (trim neutral). From a dead stop-30 seconds and 4.4.K rpm. Into the wind (light) and current took a little more time. In a light chop, she holds plane down to about 3.7 K. I can't understand the source of the problem you are having. I assume you have a pretty conventional (and correct - LH/RH and CR)prop set up, proper shaft length, and you're not dragging any oversize transducers. You might want to get a high end/certified Merc engine tech to give you an opinion. Someone other than the chap who usually does your service. They can do some load tests on the engines and haul the boat to check weight, etc. Let us know how you make out. Good luck.

Brian7son posted 05-07-2007 10:33 AM ET (US)     Profile for Brian7son  Send Email to Brian7son     

See my thread on ContinuousWave: Whaler Performance. I didn't want to repeat all the info. Essentially, I "may" have solved my problem by swapping the 4 solid PVS plugs on each of my Revolution 4 props, to a large vent hole plugs. Previously, when I hit WOT from a dead stop, my RPM's used to go to 3500-3600 and stay there for a long time before slowly chugging up to higher RPM's when trying to plane. Now, from a dead stop, when I hit WOT,it goes to 4200 RPM's and gets on plane much faster. As I stated in the other post, this test was done with 1/4 tank of gas. I'll let you know how it goes with a full tank. I also have a 5KW genset. I'm cautiously optimistic that I solved the problem.

Thanks for you input, good luck with the new engines.


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