Moderated Discussion Areas
  ContinuousWave: Post-Classic Whalers
  Re-Power: 21 CONQUEST

Post New Topic  Post Reply
search | FAQ | profile | register | author help

Author Topic:   Re-Power: 21 CONQUEST
BW21CT posted 12-16-2004 12:23 AM ET (US)   Profile for BW21CT   Send Email to BW21CT  
I have a 250-HP Mercury EFI two-stroke on my 21 CONQUEST. For better fuel econony and range, what would you recommend for re-powering? Any brand, horsepower, and two-stroke or four-stroke
jimh posted 12-16-2004 09:21 AM ET (US)     Profile for jimh  Send Email to jimh     
Does the transom of a CONQUEST 21 allow for twin engines?

The Mercury EFI two-stroke is quite fuel efficient compared to most two-stroke engines. Changing to a four-stroke will probably produce only about a 30-percent improvement. At the power level you will need, 250-HP, the four-stroke choices are limited to Suzuki or Mercury VERADO. I do not think the VERADO will be a good candidate for re-powering as you will need substantial re-rigging which will probably drive the costs to almost $20,000 for that installation.

You can find 250-HP engines in the new E-TEC from Bombardier and in the HPDI from Yamaha. These engines may not be as fuel-efficient at the four-stroke engines, so the improvement in fuel economy compared to your existing Mercury EFI two-stroke may not be as great.

If you compute the cost savings based on the modest improvement estimated (30-percent) you probably will find that the payback period will be rather long.

Peter posted 12-16-2004 10:10 AM ET (US)     Profile for Peter  Send Email to Peter     
The Conquest 21 transom does not accept twin outboards.

Actually, if you compare the performance reports for the Evinrude DI and the HPDI against the conventional 4-stroke counterparts from Yamaha and Suzuki, you will see that they are as fuel efficient as those conventional 4-strokes. Both of these 2-stroke DFI motors are substantially more fuel efficient at WOT than the Verado 4-stroke. The E-TEC is as fuel efficient as the Evinrude DI.

LHG posted 12-16-2004 02:09 PM ET (US)     Profile for LHG    
So you don't have the extra expense of re-rigging and getting rid of your Smartcraft system, you should look at the 250XS Optimax. From what I was told by some Whaler factory people, this is a very powerful engine, much hotter than the 225 Optimax, and when they switched out a pair of 250 EFI's to 250 Opti's on a new 320 Outrage, he said they couldn't believe the difference in performance and economy. Compare it's price to a 250 Verado when pricing out the Mercs. Mercury insists this 250 Optimax is the all out fastest 250 on the market today, but I don't how it measures up against the newer Verado.

Stay away from the Yamaha 250 HPDI, as stories of problems with these persist.

As mentioned you only other two choices would be the Evinrude 250 E-tec or the large Suzuki 3.6 liter 250 4-stroke

BW21CT posted 12-16-2004 08:40 PM ET (US)     Profile for BW21CT  Send Email to BW21CT     
Thanks for the information. Im wondering if i would notice a difference in the amount of emmisions and noise from my 250 EFI and the new optimax ? Also wondering if i should replace with a smaller horsepower ? I have a 1996 EFI and know that its probably not worth much and will take a long time to get the return on the money buying a new one but kind of afraid to wait too much longer.

I live in the Pacific Northwest and have some pretty rough water conditions on the Columbia river and in the ocean so i rarely see WOT so might be able to replace with a lower horsepower and probablly not know the difference. Im also looking for a little longer range so i can get after the tuna and halibut and make it back. Any suggestions ? Thanks

kglinz posted 12-16-2004 09:50 PM ET (US)     Profile for kglinz  Send Email to kglinz     
In a post made by a gentleman with the UserName of "alkar", he mentions having a source of leftover 2003 225 Hondas at a good price, in your area. That engine would great on your Conquest. Do a search for his profile.
kglinz posted 12-16-2004 10:17 PM ET (US)     Profile for kglinz  Send Email to kglinz     
Here's the post I was referring to. Took a while to find it.....
rtk posted 12-16-2004 10:26 PM ET (US)     Profile for rtk  Send Email to rtk     
I just went through the same decision making process this past spring with my 1997 21 Outrage. I am assuming it is the same hull as the Conquest, or at least similar. Please correct me if I am wrong.

The motor the boat came with was a carbed 1997 Mercury 225 horsepower. The boat performed very well and top speed was around 45. Never felt underpowered, I felt that the boat moved very well with the 225 horsepower. My boat has a large hard top t-top with an enclosure, so there is alot of drag and extra weight.

I went back and forth between the 225 Mercury Optimax and the Suzuki 250 horsepower four stroke, with fuel efficiency a goal.

I wound up with a 2003 Mercury 250 EFI. It was a great deal, $3000-$5000 less than the Suzuki and the Optimax. Since I will put around 100 hours a year on the boat the reduced engine price outweighed the potential long term fuel savings for me. The boat has a 119 gallon fuel tank so range is not a problem for me.

The 250 is great, with the right prop I am at around 2.5 mpg at 3400-3800 rpms, 25 to 30 mph cruise. I'm pretty happy with that. Not much difference top end though, running identical props.

If fuel efficiency and good performance is the goal, I would recommend the Mercury 225 Optimax. I don't think you will see a big difference between the 225 and the 250 for the way you use your boat. (same as me-not much calm water)It is light (+/- 500lbs), fuel efficient, reliable and widely available plus I think performance will be good. Use your existing controls if they are in good shape, you probably need a harness for the Smartcraft warning system.

I think you would be able to find a deal on that motor. All Mercury dealers are sent a list of non-current motors (leftover) that are available to them. Availability is sporadic. I let my Mercury dealer know what I wanted. When a motor was available he let me know. You basically have to be ready to say yes when you get the call because they go quick. I purchased mine in the winter when they offered extended warranties and rigging credits, the deal was hard to beat.

As far as noise, the Optimax and EFI 250/225 horsepower are the same block. I don't think there is any difference in noise levels. Emmisions are reportedly lower with the Optimax.

There are alot of good motors out there. Enjoy the search.


rtk posted 12-16-2004 10:39 PM ET (US)     Profile for rtk  Send Email to rtk     
Forgot to mention, I sold my engine for $4000. Low hours and very good condition. If your engine is in good shape it should still have some value.

I was offered $1500 to $2000 as a trade. I was lucky, my dealer sold my engine for me as opposed to taking it on trade.

The bass boat/performance boat guys love the Mercury 250 EFI motors.


Post New Topic  Post Reply
Hop to:

Contact Us | RETURN to ContinuousWave Top Page

Powered by: Ultimate Bulletin Board, Freeware Version 2000
Purchase our Licensed Version- which adds many more features!
© Infopop Corporation (formerly Madrona Park, Inc.), 1998 - 2000.