Thread subject: Whaler Central - Boston Whaler Boat Information and Photos :: Propping E-TEC 200 H.O. for Best Fuel Economy
Posted by Derwd24 on 10/23/09 - 8:51 PM
#1
I have a 2007 E-TEC 200 H.O. on our Outrage 22 currently running a 17" Mercury MiragePlus with good overall results.
Lightly loaded I can hit 5630 RPM at WOT and reach 46 MPH consuming 20.8 GPH. Best cruise at 3500 RPM consuming 9.5 GPH and reaching 28 MPH, about 2.9 MPG. Engine is mounted all the way up and the AV plate is still below the surface at cruising RPM and trimmed out. Boat will drop off plane when RPM's go below 3000.
Am considering trying a four blade Cyclone or VenSura to try and get a little more stern lift as well as increase fuel economy at best cruise RPM. She's a heavy hull but I have a feeling I can do better. Any thoughts or experiences are welcomed.
Edited by Tom W Clark on 10/24/09 - 6:14 PM
Posted by kamie on 10/24/09 - 6:00 AM
#2
The optimum range for the 2007 200HP HO is 5500-5600 so your right in the range.
2007 E-Tec Chart
I like the Vensura prop for cruising, it seems to make the boat ride better.
Posted by kamie on 10/24/09 - 6:59 AM
#3
If you want to try the 17p Vensura that I have floating around, PM me. i won't be down to the boat for a couple weeks.
Posted by Phil T on 10/24/09 - 7:44 AM
#4
Derwd24 wrote:
Engine is mounted all the way up and the AV plate is still below the surface at cruising RPM and trimmed out.
If your engine has the standard hole pattern, I would expect the engine to be too
high if mounted all the way up.
Posted by Derwd24 on 10/24/09 - 2:25 PM
#5
How come Phil? My AV plate is still buried and I never lose grip with the current prop.
Posted by Phil T on 10/24/09 - 3:48 PM
#6
As many have said, mounting the motor so the anti-cavitation plate is slightly
above the water surface when at cruise and trimmed out is the desired position for efficiency and performance.
I have read Tom Clark and/or others recommend mounting E-TEC's 2 holes up. I infer that would put the motor at the desired height.
If you are 4 holes up, I would expect the anti-cavitation plate to be out of the water, not still below it.
Not trying to stir the pot, just ask the question to confirm proper height before one goes out and spends a couple of Franklin's on a new prop. :~)
How bout doing a personal page with some photos so I can drool on my keyboard seeing your rig?
Posted by Whaler27 on 10/24/09 - 4:08 PM
#7
0 <-- no holes up = virtually no space between top of transom and bracket
0 <-- 1 hole up = 3/4 inch space between top of transom and bracket
0 < -- 2 holes up = 1 1/2 inch space between top of transom and bracket
0 < -- 3 holes up = 2 1/4 inch space between top of transom and bracket
Typical mounting is 1 or 2 holes up.
My experience is Mirage Plus does not hold traction well at low mid-range speeds (3000 RPM or less) with elevated mounting height (2-holes up or greater).
Consider trying a Mercury Revolution 4, 15 inch pitch.
Edited by Whaler27 on 10/24/09 - 4:11 PM
Posted by Derwd24 on 10/24/09 - 5:49 PM
#8
No worries at all Phil, I appreciate the input and was just curious as to your thoughts. Appreciate all the suggestions.
She's a heavy hull and I think that's the main reason the AV plate is still too low. Hence the thinking about a 4 blade prop and extra lift.
I've read about other 22's with same power that can get 3.7 mpg or so, but they're able to turn larger pitch than I can.
Posted by Tom W Clark on 10/24/09 - 6:48 PM
#9
The new E-TECs seem to have even longer midsections than OMC motors of the past (which are known to be longer than Mercurys).
Still, I am with Phil in being a little surprised that the AV could still be buried with the motor mounted three holes up.
My friend George put a new E-TEC 250 on his Revenge 25 Walk Through and it is mounted three holes up. The AV plate is about one inch above the keel, not much, but just about right for a Whaler.
Dave -- Have you measured the vertical distance between the AV plate and the keel of your boat using a straight edge? I am just curious. It is academic since you cannot go higher.
The Mercury MIRAGE
plus is a good propeller for fuel efficiency, in fact if you asked for my prop recommendation for best fuel economy, I would suggest the MIRAGE
plus because after testing a dozen sets of props on my own boat, that model of propeller has proven to be the best. But that does NOT mean it is the best for you and your boat.
The ultimate way to find the best prop for your boat's fuel economy is to try different props, record the numbers and do the math. Try anything you have access to.
You talk of wanting more stern lift, unfortunately, the MIRAGE
plus with its large diameter is a very good stern lifter and it may be difficult to improve upon it. Props with large diameters and low rake do well for that quality.
Another good stern lifter is the Mercury Revolution 4, which does not have a large diameter but it does have a lot of rake. Remember, every time you hear a rule-of-thumb in prop fitting, there is an exception or two, so keep an open mind.
The four blade VenSura/Offshore is not much of a stern lifter. It is a terrible prop on my own 25 foot Whaler yet I have propped two Outrage 22s with them and the owner's like the VenSuras very much. It is worth a try.
Though you will have a hard time finding one to borrow, another good stern lifter is the PowerTech OFS4 series four blade. These have a very large diameter for a four blade but the drag may be too much to achieve really good fuel economy, but again, if you can lay hands on one, try it out.
If you are hitting 5630 RPM with your 17" MIRAGE
plus then, as Kamie points out, you've got the pitch about perfect...for the MIRAGE
plus. If you try a Vensura, you will need a 19". If you try a Revolution 4, try the 17" and see how it does. The 15" may offer better performance but it will NOT offer better fuel economy.
You might also consider an 18" Mercury Enertia. I do not have extensive personal experience with these props vis-a-vis fuel economy but they grip very well, carry a load and are reported to be fast (though in testing on my own boat, they are not any faster than the MIRAGE
plus).
I do think the BRP Cyclone is worth trying too; it performs very well on George's Revenge 25 which can get just over 3 MPG with its E-TEC 250.
Posted by Finnegan on 10/25/09 - 10:46 PM
#10
Could this engine be a 30" model?
Mercury does not recommend the Vensura for 3 liter size blocks. See their prop descriptions/applications. (which is why they changed the name from "Offshore".) The Revolution-4 is the replacement.
I would recommend either the Rev-4 or Enertia.
Posted by Derwd24 on 10/27/09 - 2:39 PM
#11
Thanks for all the prop recommendations, very much appreciated.
Just measured the engine height with a straight edge on the bottom of the AV plate over to the transom. From the bottom of the V in the hull to the straight edge contact, I get between 1-1/2 to 1-5/8". Something tells me that's too low for being mounted all the way up Tom?
Good question Finn, checked the model number and it's an X which is supposed to be their 25" model.
Posted by Tom W Clark on 10/27/09 - 3:29 PM
#12
Dave -- So you're saying the straightedge is
below the keel? Or are you saying you measure 1-1/2 to 1-5/8"
up from the keel to the straightedge?
Do you have a photo of the motor mounted on the transom?
Posted by Derwd24 on 10/27/09 - 3:44 PM
#13
Sorry Tom, it's up from the keel not below. I can take a pic, let me know what angle you'd like (even with the AV plate, shot of the mounting bracket, etc).
Posted by Tom W Clark on 10/27/09 - 5:09 PM
#14
Yeah, OK, the AV plate is 1-1/2" to 1-5/8" above the keel. That sounds right.
Posted by Derwd24 on 10/28/09 - 6:34 PM
#15
Sounds like my hull may be just too heavy to get the AV plate out and get a little better fuel economy?
When I was considering the Etec, this post below really helped with the decision. Very similar set up, 3.7 mpg, and the rear fish well was full of water during initial testing, and still able to turn a 21" pitch.
http://continuouswave.com/ubb/Forum4/...03984.html