posted 11-17-2003 03:12 PM ET (US)        

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After sea trails and break-in last Friday, I went fishing on Saturday and Sunday with my 1986 OUTRAGE 25 with newly installed twin Mercury 115-HP 4-stroke outboards. I had to use aluminum props as the Stainless Steel propellers available were just too heavy for the engines. The boat had 140 gallons of fuel, 20 gallons of water, a full bait tank (30 gallons). and three adults aboard.

2100 RPM = 7-8 knots trolling
3000 RPM = on plane
3100 RPM = 18 knots cruise
3500 RPM = 23 knots
4000 RPM = 28 knots
5500 RPM = 37 knots

We ran out 1.5 hours at 3300 RPM, trolled 7 hours at 2100 RPM, and ran back 2 hours at 3400 RPM. Fuel consumption was 40 gallons.

Thanks for all the advice.

See the original topic for more information.

posted 11-17-2003 05:09 PM ET (US)            

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Hector, is the 5500 RPM at wide open throttle (WOT)? If so it sounds like you are propped OK with the aluminums since the maximum RPM at WOT for those engines is 5000-6000.

How high are the engines mounted?

Did you measure fuel usage by refilling, flow meter, or both?

posted 11-17-2003 06:46 PM ET (US)            

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Barry:

They should give me 6000 RPM but I screwed up the installation of the stereo. It is installed above the control/shift box and the control levers don't go all the way. I have to fix that in the future. (I think they go all the way but I'm not sure.) The Port engine is 100 ± RPM lower than the starboard engine. The engines are mounted in the original 20-inch notched transom. The boat is a 1986 25 Outrage. I fill the gas tank before and after each day trip (to compute the fuel used).

posted 11-18-2003 08:30 AM ET (US)            

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I assume those are Merc Black Max props? What diameter and pitch did you use?

Thanks,
--
Moe

posted 11-18-2003 09:45 AM ET (US)            

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Knots and MPH are related by 1:1.15

See http://www.howstuffworks.com/question79.htm

posted 11-18-2003 10:31 AM ET (US)            

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Moe: Propellers are alluminum 17Pīs.

And Barry: She popped right away, I didnīt instaled trim tabs, but not gonna; she leans a little to port when have the bait tank full (30 gallons on the stern-port side) but just a little, if move a little the load to starboard or adjust the trim of the engines the problem is corrected. Iīm VERY happy the way this boat handles with this powerplant. Very quiet, and you actually feel the power going thru the followin seas. Not too fast (37 knots/42 mph) But She cruises very comfortable @ 23-25 knots.

posted 11-18-2003 01:55 PM ET (US)            

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Ps I think he carries like 170 gallons of fuel and is gona have his tank cut down to 120 being he does not need 170 nor the weight. The problem with just leaving it the way it is, is the weight is too far aft. He wants to move the tank up a couple/few feet but can't so only choice is to shorten.

My point is now that you can run all day on 40 gallons instead of 80, you may want to run 1/2-3/4 of a tank instead of full. 140 gallons of gas weighs about 1000lbs. If you can troll slower, the 115's will burn about .5gph(combined) at 1000 rpms at about 6mph. Running 2100 is about as inefficient of a speed you can run. I know it depends on what you are fishing for but If you can slow down to 1000-1500 rpms while trolling you will save about 10 gallons a trip.

posted 11-18-2003 02:21 PM ET (US)            

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Now I'm wondering why I'm only getting 40mph out of my 22" Outrage WD with twin 2000 Honda 115's. Shouldn't my 22' be significantly faster?

I wonder how much of a difference I'd see if the tabs in the throttle bodies were to mysteriously fall off (allowing the motors to develop 130 hp).

posted 11-18-2003 02:39 PM ET (US)            

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Alkar....your whaler drive is the reason and hence why they rate the boat at 300hp instead of 240. I doubt a tab makes the difference, if s remove it. On my 70 suzuki the ECM is what makes mine a 70 compared to the 60, it costs about $1200 to upgrade to a 70hp ECM.

Whaler 27....I would NOT go with 175's on a 27'. That is a heavy beast and with a 450-600hp max rating, 350 will be too small. The E-Tecs are only up to 90hp, the Ficht are from 100-250hp. I would shop around, I have seen 2002 Yamaha 225 4 strokes as a pair for $21k used(200 hours?). That might be an alternative. The problem with the 175's are they are a smaller block, you need the torque of a bigger bore engine. On the flip side, in "striking distance" Bruce Willis ran a 27 with twin 150's but I bet she was a low 30's mph machine.

posted 11-18-2003 03:38 PM ET (US)            

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Bigshot:

I also felt that 2100 rpmīs is very inefficient, but it was the speed I wanted for the 7-8 knots on a flat sea when I troll for marlin/dorado. 1500-1600 rpmīs giveīs me about 6 knots, when itīs choppy marlin lures work OK, but real close to the boat and there is a lor of white water there. I think itīs going to be a matter of adjusting things up. 10 gallons a trip x 6 trips a month = lot of pesos.

Also I have yet to try dead bait trolling, it should work between 1300 and 1600 rpmīs.

Thanks again.

Hector

posted 11-18-2003 05:58 PM ET (US)            

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Big. Even after reading the threads discussing the performance changes resulting from brackets of various kinds, I don't understand why my boat would require more horsepower to perform like the 25' w/115s. The 25 is a MUCH bigger, heavier boat.

On the Hondas: I assumed that 115 and the 130 was an ECM too, but the local Honda mchanic told me it was just a mechanical tab in the throttle body that prevented the 115 from opening all the way up. (I'm planning to look at my old Honda brochure from 2000 to see where each motor builds it's hourspower.)

Alex

posted 11-18-2003 06:32 PM ET (US)            

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OK - about 10 min actual research tells me that I wouldn't save nearly as much as I thought... 175's are only about $500 cheaper than 200's, which are only a little cheaper than 225's, which is what I really need.

I guess I knew it already, but I'm just trying to find a way to avoid spending over $20K on a repower - but it probably just ain't gonna happen.

Once again in the market for 225's... Ficht or four-stroke...

posted 11-18-2003 06:41 PM ET (US)         

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Alex, there is not as much difference in your boat and AM's notched transom 25 as you would think. The hull weight difference is 1000#, but his engines are 250# lighter, and hull wetted surfaces are close to the same. The engine brand could make the rest of the difference on the 750# actual weight difference. The Mercury/Yamaha EFI's are definitely more powerful than the Honda 115's. They will probably run with the Honda 130's or Suzuki 140's. For years now, Mercury has advertized the 135 Optimax to be 5 mph faster, and get better gas mileage, than the Honda 130, and Clark Roberts has indicated his 135 Opti would run about 5 mph faster than his Merc 115 4-stroke on same Revenge. So the Merc/Yamaha 115 & Honda 130 are about same HP output.

I seriously doubt that a pair of 115's will push a 25 much over 42. Even that is pretty good, if you ask me. You might check with Outrageman on his performance experiences with twin Merc 115 EFI's on a 22 WD. I think even a strong pair of 115 (such as my lightweight in-line 6's) 2-strokes would only be able to push a 22 WD 45mph at most. To get 50 out of a 22WD, you need a pair of 60 degree V-6 150's. A 25 would perform the same with this power. I don't know why.

posted 11-25-2003 09:04 PM ET (US)            

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Basically you have to think in the difference in how heavy in the stern was before and after. And diference in Horsepower (Before and after)
My boat had twin 150 Yamahas, (100 pound heavier) and I loose about 25% in total horsepower. Lost about 8 mph top speed. (Thatīs what the guy who sold it to me told me)

HECTOR

posted 11-25-2003 11:40 PM ET (US)            

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Twin engines on 22 Revenge Whalerdrive is O K.

I would avoid putting twin engines on any of the 22' models with the open transom, particularly the ones with the original splashwell. Those engines will be swimming, and you'll have soggy topsiders. There are several threads dedicated to this subject.