23 Venture performance numbers.

Matt-
What is the pitch on the 15" prop for the 115?

I have a 90hp ETEC and I think I am over proped. I am at 4800 at WOT.

I have had the motor for 18 mo. and have put about 500 hours on it. I love it.

-Tim
 
Foggy,
I posted my fuel numbers years ago when I first got my boat. They are somewhere in the archives. I averaged around 4mpg from Swantown (Olympia) to Everett. Don't exactly remember. Some of the sleuths on the site can probably find them.
Forrest
 
The 90 hp e-tec usually uses a 13 .25 to 13. 5" diameter prop. Although the book WOT is 4500 to 5500, 5000 to 5200 is better. First be sure that your engine is mounted correctly. The anti ventillation plate should be just on the sufrace of the water when running fully on a plane, with the engine trim neutral. Some boats are rigged with the prop too deep. If you have a 15" prop now, you might do better by dropping down 2" pitch to 13". If you have a 17" then drop down to a 15".
 
thataway":gi7r11fj said:
The 90 hp e-tec usually uses a 13 .25 to 13. 5" diameter prop. Although the book WOT is 4500 to 5500, 5000 to 5200 is better. First be sure that your engine is mounted correctly. The anti ventillation plate should be just on the sufrace of the water when running fully on a plane, with the engine trim neutral. Some boats are rigged with the prop too deep. If you have a 15" prop now, you might do better by dropping down 2" pitch to 13". If you have a 17" then drop down to a 15".
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When I was running my 28' offshore deep V w/twin 502 cu Merc MPIs, the critical stern perforation for the outdrives above the lowest point of the hull was called "the 'X' dimension". OK, this rig is not an outboard setup. Still, the mounting of the engine(s) is somewhat critical for WOT MPH, MPG at cruise, etc and usually out of the customers control and set by the dealer who does the engine installation. So, how is the average bloke to know? It is impractical to mess around changing engine heights and propellers. What exactly are you saying?

Aye.
 
Foggy, outboard motors are entirely different than I/O, which have a cutout in the transom. They outboard engine bracket has a number of holes in it which allows adjustment up and down. An outboard motor is easily moved up and down on the transom; I use an "A" frame or a sturdy tree limb and a come along or a chain hoist to take the weight of the motor, remove the bolts and then move up or down the appropriate amount. There are a variety of other ways to do this. Before Tim changes props, we need to know that the outboard is set properly. I happened to own the boat that Tim owns now about 5 years ago. At that time the outboard was a 1996 Evinrude which was properly set. The engine got 5500 RPM at WOT with the correct prop on it. 15" pitch for seal leavel and 13" pitch for Lake Powell. Tim has put a new engine on it recently. We do not know if it is properly set. An outboard which is set too low will not achieve proper WOT, even with the best prop. To be technical we don't know if his tach is accurate either, and some would check the tach (which is also fairly easy to do).

We do not know what prop Tim has currently on the boat. However I suspect that it is not 15" diameter, since that diameter will not fit on a 90 hp E- Tec. I am suggesting that if he has a 15" prop and wants to bring the RPM up 400, he should drop the pitch by 2" Of course there are many other things which can be varied in the outboard prop--such as cupping, rake and number of blades.
 
If I were the betting type, which I'm not, I'd bet I'd be making a very safe bet if I bet fewer rather than more CD owners had a chain hoist dangling from a tree near their driveway or in their garage to adjust the height of their stern mounted outboards to get more or less 500 RPM or had a suitcase with with even a small selection of different props to change for the altitude of their next mountain lake cruise.

By the way, who is Tim?

Aye.
 
Foggy, If you look at the bottom of the posts by tpsurf the name of the boat owner is "Tim". (Although I know his full name, I am not disclosing it.) The suggestion of use of a come-a-long or chain hoist is only one way of raising the motor if necessary to have it properly mounted.
The question was about gaining more RPM at WOT speed and pitch of a prop. Some people do want their engines mounted properly and running at full rated RPM as specified by the manufacturer as it is easier on the engine. In this specific case the engine is already running at the lower range of spec RPM.

As for props of different pitches, you will find that a number of C Brats who run at Lake Powell (Altitude 3700 feet) will have a pro;p 2" lower pitch than what they run at Sea Level. Boats run at Yellowstone or Tahoe (7,000'), which a number of C Brats do, they will have a prop of 4" less pitch than the sea level prop. These are just a sample of lakes where the engine is reduced in horsepower because of the altitude and a different prop is required for the best effeciency and best for the engine.
 
To further the point made by Dr. Bob about multiple props: Although I run exclusively at sea level, I have two sets of props. One is for "ordinary" use when the boat is likely to be on the light side. The other is for long-range cruising, such as two months on the Inside Passage with extra fuel, extra food and water, generator, life raft, survival suits, and all manner of other heavy stuff. That way I can keep my WOT RPM in the 5500 to 6000 recommended range. Just like elevation, weight can affect engine performance and prop requirements.

For what it's worth, subsequent trips have confirmed almost exactly the MPG reported in my earlier post. On long trips with a heavy boat I average about 3.3 MPG.
 
I think that Forrest is right in that the CC hull design of the 23V and 26M may have less hull resistance when powered through the water. Too many owners have posted MPG numbers equal to or greater than those achieved by the 22. I hope to run accurate "real world" checks on our 23V powered by a 150 Suzuki. We generally run our boat heavily loaded (like Forrest's 26). Unfortunately, this year, I don't have a fuel flow meter to make more precise trials (will post results next year).
 
Back in 2010 I posted performance numbers for my CD26V and they were met with some skepticism. I am reluctant to provide them again, as I am not thrilled about my math, honesty, or sanity being questioned; however, I'll grin and bear it...here is the performance that I have measured. The boat is rigged with a 175 etec. I carry a 9.8 Tohatsu kicker, 3 gal tank, and a 2K Honda generator. The boat is moderately loaded with other equipment. My last fill up a couple of days ago was just under 70 gals. My performance in GPH was 4.32. I generally run between 15 and 18 knots. I probably run at 25 to 30 knots less than 10% of the time. I only run less than 15 knots when leaving the dock or in a no wake zone, so again less than 10% of the time. I get about 12 hours on a gallon of oil. The performance I measured back in 2010 was about 3.2 GPH in the 15 to 18 knot range and about 5.5 GPH in the 25 to 30 knot range. I haven't repeated the measurements since that time, but have no reason to believe that the numbers weren't accurate. The math is simple, gallons to fill the tanks from the gas pump meter divided by hours from the Evinrude I-command meter. Hope this helps anyone thinking about a CD26V and/or etec.
 
Morning star-how many miles did you go from fill up to fill up when used 70 gallons? For example if you went 210 miles, you would have gotten 3 miles per gallon. You should be able to read miles gone from your GPS. Most GPS have "total" and "trip",
 
I have always figured by miles per gallon at certain speeds--or a known mix of speeds. That way you know how far you can go with the amount of fuel. If you have a long trip, then you know how far you can go at displacement speeds. For example with the 25 I had one run which was going to be 250 miles. So I ran a certain amount of that a low speeds to be sure I had the range needed. I have flow meters on several of the boats, and it does help establish the amount of fuel burn at each tach speed (which equals to boat speed).
 
4th of July weekend my wife and I did a cruise from Everett to Port Townsend, Port Townsend to Friday Harbor, then Friday Harbor back to Everett in a loop fashion around Whidbey. From Everett to PT to FH was 75 miles I believe and 19.1 gallons of fuel and we had not the best of conditions with the wind on day one to PT. On the FH to Everett leg we tooled around the San Juan's for a couple hours as well. Total trip was 168 miles on 41-42 gallons of fuel. Two people, full fuel, 3/4 water and gear for 3 days. I have a 23' Venture with twin Yam 60's. Day one we got beat up in sloppy seas doing 12-15, day 2 was better and did 18-20, day 3 was beautiful and did 25-30mph. I was impressed at the fuel efficiency.

Troy
 
thataway":uuv66esr said:
I have always figured by miles per gallon at certain speeds--or a known mix of speeds. That way you know how far you can go with the amount of fuel. If you have a long trip, then you know how far you can go at displacement speeds. ....SNIP....
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Knowing your cruising range/tank of fuel is basic if wanting to reach your destination or return home is important to you. Besides that, safety should be figured into your fuel tankage.

For safety's sake, fuel calculations for a round trip should include the "Rule of Thirds": 1/3 of the tank to get there, 1/3 of the tank to get home, 1/3 of the tank to handle an unforeseen situation.

Aye.
 
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