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Prop Advice for 1999 18' Outrage with Honda BF150
|Author||Topic: Prop Advice for 1999 18' Outrage with Honda BF150|
posted 06-09-2004 12:09 PM ET (US)
As some of you know, I recently purchased a 1999 18' Outrage and repowered it with a new Honda BF150 4-stroke engine. After losing time to a bunch of crappy weather and a busy schedule, I am finally most of the way through the 10 hr. break-in period. Now I am able to run the engine at WOT for short periods of time.
I'm finding that the overall performance is good, but not spectacular...I want to see if I can get it dialed in better with the help and advice of the forum members. I'd like to work on time to plane, top speed and RPM's.
Remember that this is the Post-Classic 18' Outrage. LOA is 18'4", Beam is 8'3", Hull Weight is #2500, Honda 150 is 486 lbs. All rigged up and full of fuel, it is between 3500-4000 lbs.
Getting the boat on plane with 1 or 2 adults and a full (90 gal.) fuel tank is pretty fast, but I think it could still be a bit quicker. With 4 adults and a full fuel tank, it struggles some to get on plane, but runs fine once it is planing. There is no real porpoising as long as the engine isn't trimmed up too high. There is plenty of mid-range power and the boat is very responsive. I am considering adding trim tabs...I am used to them on our other boat and I know they would help here.
At WOT with 1 person aboard, on fairly flat water, I hit a top speed of 39.8 mph (GPS) at 5200 RPM. The redline on the Honda 150 is 6000 RPM, so I am falling far short of that. The current prop is a Rapture (Stainless Steel) 14.25x19. The engine is currently rigged all the way down...on the first hole. I am thinking about raising the engine at least 1 hole...maybe 2.
What do you think?
posted 06-09-2004 01:01 PM ET (US)
I would consider raising the motor 2 holes and go with a 14.25 X 17 pitch stainless prop. That should get you closer to the higher end of the rpm range.
posted 06-09-2004 01:11 PM ET (US)
As everyone here knows, my familiarity is with Mercury Props, but they will fit Hondas with the Honda hub kit. Assuming you have a Rapture with interchangeable hub, that hub (which is licensed from Mercury) will take any Merc prop also.
Tom, you have two apparent problems. A heavy boat for a single 150, and the 150 horses is from a 4-stroke, many of which are weak in acceleration relative to the twice as many power strokes you get from a 2-stroke.
You need a prop with lower pitch and more blade surface than the Rapture or Stiletto props offer, which are basically similar to a Mercury Laser II speed props. If your boat was a Classic 18 Outrage, that prop would be all right, but not for your heavier model. More blade surface is needed to carry the heavier load you are pushing. Mercury Mirage Plus in 3 blades (a larger diameter prop), 15" pitch comes to mind, as does the 4 bladed Offshore (now called Vensura) prop, but it is not offered below 17" pitch, so that could be problem. This 4 bladed prop is known for fast acceleration, but not maximum top speed.
In either case, the engine should be raised at least one hole.
I would check with BW, and see what kind of prop and pitch they shipped on this boat when rigged with a 150 HP Merc. I'm betting Mirage Plus
posted 06-09-2004 02:07 PM ET (US)
According to the prop calculator here, your propeller is getting adequate grip (less than 10 percent slip) at WOT so I don't think that blade surface area of the Rapture propeller is the problem. Rather, your problem is simply the motor is mounted at least one hole too low and you may be overpropped. In your normally loaded condition, your Honda should be rigged so it can spin at least 5500 RPM at WOT.
Before testing or trying any other propellers, I would start by raising the motor one hole and see where your tach ends up at WOT. You should gain RPMS but will probably fall short of 5500. From there, you can try going up another hole or drop down to a 17P prop. With the engine raised one hole, I believe that a 15P propeller will not have enough pitch to keep your Honda under 6000 RPM.
Give the engine lift a try and let us know how it works out.
posted 06-09-2004 06:11 PM ET (US)
Everything I have read about engines indicates that with a light load giving 5200 RPM, the engine should be propped to max RPM of 6000 for best performance, particularly to correct sluggish acceleration when loaded. That's why I think a 15" prop is needed.
posted 06-09-2004 06:26 PM ET (US)
I think he might gain 100 RPM or so from raising the motor, that's why I suggested that he do that first and see where the tach needle points at WOT. Once that is done, then the propeller requirement can be fine tuned. If the Honda gains 100 RPM from the lift and each inch of pitch reduction yields another 200 RPM, then a 15P should put the Honda over the 6000 RPM limit.
posted 06-09-2004 09:59 PM ET (US)
Thanks for the replies, guys! Very helpful and lot's of good info.
Larry - as you surmised, the Rapture does use the Mercury interchangeable hub system. You mentioned going to a larger diameter prop....what will that accomplish? Is that just to get the increase in the surface area of the blades that you were talking about? Will that affect acceleration and planing or is that more a function of pitch?
Peter - I have thought about moving the engine up a hole or two. I haven't had a chance to see where the anti-ventilation plate is in relation to the bottom of the hull so I need to take a look at that. I understand that raising the engine will increase RPM's somewhat...are there other things that I can expect from raising it? Will it affect the acceleration and planing?
I should mention that I am not really a speed freak...40 mph is probably plenty fast enough for me. But I know that the motor isn't at it's most efficient as it is set up, so I'd like to get it to turn 6000 (or close).
posted 06-10-2004 08:52 AM ET (US)
Raising the motor may affect acceleration some but probably not much. It may affect planing attitude as the thrust cone is a little bit higher relative to the keel. It may affect the steering sensitivity as you will have a little less "rudder" surface in the water.
When I acquired my 18 Outrage, the motor was set two holes up. Smooth water speed and acceleration performance were great but the rough and choppy water performance suffered a little. I eventually struck a balance between speed, acceleration and rough water performance by dropping the motor down to one hole up. Rough water grip improved but top speed suffered some. I recall losing about 100 RPM at WOT in the transaction.
I wouldn't rule out trying Larry's suggestions for propellers with greater blade surface area. However, keep in mind that the Honda 150 turns a propeller through 2.14:1 gears and a two stroke 150 turns a propeller through ~1.86:1 gears. WOT engine speed changes from propeller pitch changes are going to be more drastic for the Honda than they would be for the conventional 2-stroke gearcase. If you are turning 5200 RPM now and getting 39.8 MPH, then, everything else being equal, the propeller calculator in the reference section of ContinuousWave estimates that a 15P prop will put your Honda over 6300 at WOT. (Because the gear ratio is higher on the Honda, you may also gain more RPM from the engine lift than might be the case with a conventional 2-stroke.)
We really won't know how good that estimate is unless you give it a try. ;)
posted 06-10-2004 09:58 AM ET (US)
Tom, it's a bit of apples to oranges, but I am turning a Yamaha Saltwater Series 15.25" X 15 pitch wheel on the Yamaha 150 HPDI on my McKee Craft 196.
The combination of MORE diameter and LESS pitch gives me tremendous holeshot and terrific mid-range performance. Top speed probably suffers a little, but how often do you run at WOT?
I think you would benefit from a similar sized prop. I'm not familiar enough with the Mercury or Michigan Wheel models to make a specific recommendation but that's the direction I would look in.
posted 06-10-2004 02:59 PM ET (US)
I would recommend a look at mercurymarine.com's propeller descriptions and applications, which take into consideration boat type and engine HP. Regardless of brand, these are pretty universal principles they're talking about in prop application.
Mercury indicates that for carrying (ie acheiving hull lift to decrease water resistance) heavier boats (in relation to HP) need more substantial prop blade surface.
The other desireable feature of the Merc props is the adjustable venting, which GREATLY aids in ACCELERATION, and which seems to make sense for 4-strokes. With something like a Mirage Plus, medium sized vent holes (plastic inserts) can be selected, to aerate the prop blades, giving controlled slip, and allowing the engine to gain RPM faster, enhancing acceleration.
None of this means that one of these Mercury props is right for a 4-stroke Honda. I simply have no experience with 4-strokes.
I still think a call/E-mail to Whaler makes some sense, for engine mounting height and style of props they shipped with the boat
posted 06-10-2004 07:17 PM ET (US)
My gut feeling is a 14.25 x 17 & raise the engine at least 1 set of holes is going to put you real close to 5800 rpms.
That 19p is just to much pitch for that 150.
A 14.25 x 16 [ good luck finding a 16p ] & raised 1 set of holes should put you right at 5900 rpms.
posted 06-10-2004 09:05 PM ET (US)
Thanks, everyone! It sounds like there is a lot of agreement with raising the engine 1 hole...I'll try that first and report back on the results.
Then, it looks like a drop down to 17" pitch is in order. I'll do some reading on the mercurymarine.com site as Larry suggests about the differences between series of props. My dealer will exchange the 14.25x19 Rapture for another Rapture...guess I'll go with the 14.25x17 for now and see what happens. I might try a Mirage Plus at some point to compare.
Gordon, how much does your 196 weigh? Even though you are running a HPDI, that might be a good comparison...but I don't think it's as heavy as the Outrage.
Sal...I think your experience is right on...and when you, Larry and Peter all pretty much agree...that is good enough for this rookie.
posted 06-10-2004 11:30 PM ET (US)
Hull weight............. 1950
Your Outrage is probably 500 pounds heavier.
I checked out Honda's web site and they also sell their own 15.25 X 15 prop, it's model 58333-ZY3-A15CL. Check out their performance tests on the web site. They test my boat with the BF150 and they used a Powertech 15.25 X 17 prop, I bet the 15.25 X 15 would be a good fit for your boat.
posted 06-11-2004 08:37 AM ET (US)
A Yamaha 150 HPDI is turning its propeller through 1.86:1 gears so the above mentioned distinction between 2 and 4 stroke gearcases applies to the HPDI.
posted 06-11-2004 10:39 AM ET (US)
Thanks again for all the input! I've done some reading on another forum (Bass Boat Central) posted by a Honda factory tech who specializes in propping and tuning Hondas for the pro bass circuit. He has some very interesting observations that I thought you all might be interested to read(I've bolded a few pertinent comments):
1. Helped a customer with a Triton TR186 with a Honda 150hp engine today. The customer bought the boat with a Tempest propeller and was very disappointed with loaded holeshot and hoped for more top end speed. On top end the engine turned the OFX-22 3-blade propeller 6100 rpms. Lift and feel of the boat was excellent. The boat had no weight (tackle or whatever) in the front compartments. Weight in this area would only increase holeshot.
2. The limiters are set on the Honda 150, 200 and 225 at 6400 rpms. I usually need around 6000 rpms to make the engines perform to two-stroke standards. I run my 225 at 6100 - 6150 all the time. The 150 I tested last summer ran 6200 - 6300 rpms the entire summer. I PREFER not to exceed 6200 for extended times - but that is my preference.
3. The information you received from Power Tech was a good general statement for two-stroke applications, but adding port holes to a Honda beyond 5/16" will not help holeshot. Please contact Bill Leonard (or ask for Steve Powers, the owner of Power Tech). Both of these guys have been involved in extensive testing of exhaust ports with the Honda. To this date, I can NOT improve performance with exhaust ports. Believe me, I wish it would work!! To be noted, we have on several instances deteriorated performance by increasing the size of the exhaust holes.
4. I have just received a new ultra high rake propeller that has been in the development stages for over a year. When my testing is complete, production will follow. This is a new 200 - 225hp prop. Also, PowerTech has had good test results with a PTR series propeller for the 150hp Honda. I will be testing this propeller in the next week. The results of which I will post on this site. This propeller is in production now! In preparing for a new Bass and Walleye Magazine test, I did get a chance to run the PTR propeller with a 90hp Honda mounted on a 170 CC Triton aluminum boat. The results were impressive. Again, I will keep all informed of my findings on the 150hp. Honda is committed to providing the best performance products available for their customers. The development will be never ending.
posted 06-11-2004 11:30 AM ET (US)
Tom, a word of advice. While you are within the warranty period, don't run your motor above 6000 RPM. Don't give Honda any reasons to deny warranty coverage in the highly unlikely event that you need it.
I agree with the observation on the PowerTech prop. Based on discussions here, they seem to have an actual pitch that is higher than the nominal pitch by about one inch (e.g., a nominal 17P will act like an 18P made by others).
posted 06-11-2004 01:41 PM ET (US)
That's good advice, Peter. I hadn't planned to exceed 6000 rpm, but I find it interesting that the motor runs strongest near the redline. As you say though, no reason to give them an excuse to deny warranty coverage.
In reading the Powertech website, they mention that the OFS props are very similar to the Mercury Mirage series...just as Larry recommended.
posted 06-11-2004 02:09 PM ET (US)
I am currently running the 4 blade OFS Powertech prop on my 1997 21' Outrage. It is a 15.25 inch diameter prop. The prop I started out with was a Vensura Offshore 4 blade in a 17 pitch and RPMs were a little over the 5800 max for engine. When I went to order the Powertech I chose a 17 pitch. A tech from Powertech recommended a 16 pitch to get to max RPM's. With the motor now at it's proper height (one hole up) the RPM's are dead on 5800 at wide open throttle.
The large diameter props really are aggressive and will run at lower RPMs than a similar pitched smaller diameter prop.
The boat jumps right up on plane and midrange power and handling is excellent.
The recommendations by Larry and others regarding the large diameter Mirage props for these heavy boats has been right on the money based on the results I have seen with my boat.
The combination of conservative engine height and the large diameter prop has made a world of difference in the way the boat handles.
posted 06-28-2004 09:56 AM ET (US)
I just got the boat back from the dealer with the following changes: Engine raised one hole (now on second hole), 14.25x17 Rapture prop installed.
It was quite windy on Saturday when I was testing it for the first time, but I was able to achieve 5800 rpm at WOT...an improvement from 5200 rpm with the 19" pitch Rapture. I observed a top speed at WOT of 42 mph (GPS)...up from a previous top speed of 39.5 mph...not bad considering the conditions. Time to plane seems quite a bit better, but I don't have any actual measurements, just subjective impressions.
I still think there is room for improvement with a larger diameter Mirage-style prop per some of your suggestions, but I am pretty happy with the performance at this point. I'm looking forward to testing it on some flatter water to see what the real numbers are.
posted 07-04-2004 12:50 PM ET (US)
Nice posting gents!
posted 07-06-2004 07:28 PM ET (US)
A little follow up, this past weekend I tested a 17 pitch Mirage. Wide open throttle RPMs were the same as the 16 pitch 4 blade Powertech. Load on the boat and conditions were identical in the test runs. The Mirage seemed to give me about 1 more mile per hour top speed. But the Mirage ventilated like crazy prior to planing, it would not bite as I powered up (brand new prop and hub kit out of the box). Put the Powertech back on and she jumps right up on plane. The Powertech seems to be one aggressive propeller if that is what your are looking for.
posted 07-07-2004 10:18 AM ET (US)
Thanks for the follow-up info, Rich. Based on your input and some other conversations with Honda folks, I am inclined to try the Powertech 16p props...not sure whether to go 3 blade or 4 at this point. I certainly wouldn't complain about better acceleration and I'd like to wring the last 200 rpm out of the motor and get right to 6000 at WOT.
posted 07-09-2004 11:21 AM ET (US)
If it were me, I'd get a 15p & put a bit of cup into it to equal a 16p, that should put you right at 6000 rpms.
I really don't think you need more than 14.25 diameter, but that depends on who's driving the boat, as we all like our boats to handle differently.
My self, I like her very light at the bow for a nice soft ride with plenty of air under her, just before she starts to porpoise.
posted 07-09-2004 03:41 PM ET (US)
Thanks for the input, Sal! First off let me say that I'm glad to hear you are alright...hope everything continues to be ok.
Being somewhat a newbie to this prop stuff, is putting cup into a prop something I would have a local prop shop do? My dealer, great guy that he is, certainly can't do this...just wonder who I should be talking to. I think that Powertech, being a somewhat custom manufacturer, will do this if I order a prop from them. Any suggestions would help.
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