MacGregorSailors.com

DaveC426913 wrote:How much can I expect to lay out for a prop, if that's part of the problem?

About $100.

I run a Michigan Match 12 1/4" x 9" 3-blade aluminum, which I bought from Deep Blue Yacht supply, and it is perfect, with RPM of 6000 - 6200 at WOT. The motor is a Johnson 50hp 4S, with 3 1/4" gearcase.

I think the Honda BF-50 has the same gearcase as the Johnson 50.

http://www.deepblueyachtsupply.com/prop ... px?egid=16

Roger

I have the Honda 50 on my 26M and back when I had the virgin white hull bottom (no anti-fouling paint) empty ballast lightly loaded with just my wife & I we got WOT 6000rpm @ about 18 MPH, not bad at the time. Today I am heavily loaded and have bottom paint so I am lucky to get 12-15 MPH. I have the Solas Alcup 4 X 11.4 X 10 and there is no singing noise but the trailing edge does have a slight cup edge to it which grips a better bite on the water. It does help to match the prop to the boat and weight and it also helps to empty the ballast for WOT tests, after all it is a hybrid boat which can be used as a power boat. Dump the ballast!

Doctor Z wrote:Don't buy the Solas prop. It does perform much better than the 3 blade stock prop that came with my BF50 however they all make a really LOUD annoying "singing" noise between c. 1500 and 2400 rpm. It is likely to drive you crazy. Apparently, you can take it to a prop shop and have the trailing edge filed sharper to cure this but I haven't done it yet. I suggest you search for Solas +singing before buying.

So I should send the Solas Amita 4 x 11.8 x 9 back and get either the :
Solas Alcup 4 x 11.4 x 10
Vortex 4 x 12 x 9
Michigan Wheel 3 x 11 3/4 x 10
Stick with the Stock Honda prop

FWI: Light boat (at least for now) Sounds like we need a vote here

Re: top speed Honda 50Hp

Postby frede » Sun May 22, 2011 7:39 pm
After several days of scouring the forums' I decided that the Solas Amita 4 Blade 11.8 x 9 from iBoats.com was the way to go for my Honda BF50A.

Thats what I found for props too. I have a 2002x with bottom paint. With a bare empty boat and 2 people the stock 3 blade prop did 16-17mph at about 5700rpm. Once I loaded the boat down for cruising it would only get to 4400 with ballast and 4800 empty on the stock prop. I picked up the amita 11.8x9 and now it does about 5000rpm ballast in or out. About 11.5 mph ballast in and 13.5mph out. So unfortunately I think 8.8knts or 10mph full ballast 4 people may be about right. It sounds like you are buying the boat, so check the full throttle rpms next time. Full rpms are 6000, so if you are getting substantially less it may be the prop.

Don't buy the Solas prop. It does perform much better than the 3 blade stock prop that came with my BF50 however they all make a really LOUD annoying "singing" noise between c. 1500 and 2400 rpm. It is likely to drive you crazy. Apparently, you can take it to a prop shop and have the trailing edge filed sharper to cure this but I haven't done it yet. I suggest you search for Solas +singing before buying.

I read about that but did not have this at all with mine, did get the amita or a cup?

I have tried 5 diffrent props on my MacX and 3 of them were 4 blade Solas,Alcup/Altima . I have reported the singing at lower rpm's but my current Solas does not sing. Maybe because of the change of hubs and also the pitch.
I get 16-16.5 mph top end on a heavy loaded boat ,no Ballest in less than a 1 ft. wave.
My pitch is 11 and I wanted a 10 pitch but they don't make it in a 11.8 dia. 4 blade prop.
Since I cruise at 6 knots the higher pitch alowes me lower rpms but not much and rpms are only 4800 at wide open.
I chose the pitch because of my cruiseing and not top end.
Without a doubt a outboard that will allow a larger diamiter with a 3 blade is much better like the Big Foot Merc's or Yamaha or the E-tec 60 for a 50--60 hp outboard. Prop is at least 2 inches greater in diamiter and geared for lower speeds. (around 15-18 knots)
I can take my prop down to Burris down the street and change the pitch to 10 but that would only give me a 200-250 greater rpms. and I don't think the $50 cost would be worth it.
If a 4 blade slightly cuped 11.8 x 10 could be found for the Honda bf50 than that would be a good fit at the lower end of rpm's for a empty ballest heavy loaded boat. Two years ago I couldn't find one.
My outboard is in top shape but is 14 years old and have not done a compresion test on it.
Dave

Doctor Z wrote:Don't buy the Solas prop. It does perform much better than the 3 blade stock prop that came with my BF50 however they all make a really LOUD annoying "singing" noise between c. 1500 and 2400 rpm. It is likely to drive you crazy. Apparently, you can take it to a prop shop and have the trailing edge filed sharper to cure this but I haven't done it yet. I suggest you search for Solas +singing before buying.

DaveB wrote:... I wanted a 10 pitch but they don't make it in a 11.8 dia. 4 blade prop...

iBoats list a Michigan Wheel 4 x 12 x 10 for the Honda 50, sounds like that might be the ticket, although the girlfriend does like to go fast, so I don't want to drop speed This weekend I hit 16 knots @ 5000rpm (WOT) with the current 3 blade, GPS speedo, 2 people, no ballast, 12.3 knots max, on the way back. I think I'll change the GPS to MPH, it'll make me go faster

Hi

I have a 2008 fuel-injected BF50 and although I have seen almost 17kts, I now tend to max out a little lower than this (mast on, ballast out, decent amounts of kit on board, new antifouling paint etc).

To my mind the BF50 is a truly awful engine; firstly, it is identical to the BF40 except for the ignition mapping software, which means that for most of the rev range you get the torque and general grunt associated with a far smaller engine. Secondly the cav plate and rudder skeg seriously restricts the diameter propellor you can select, and I am a firm believer in blade surface area over pitch.

The longer I have had the the less concerned I am about outright speed under power; sure, 10 - 12 kts to get the boat up out of the water around 4,500 revs, but above that the fuel economy really drops off badly; I would far prefer to have a massive prop which could consistently smash me through lumpy seas at high displacement speeds, but the Honda isn't able to swing one

magnetic wrote:I would far prefer to have a massive prop which could consistently smash me through lumpy seas at high displacement speeds, but the Honda isn't able to swing one

This is what the two stroke E-TECs are excellent at. They have so much torque that the final drive is 1:2.7 vice 1:2. They take the deep props well and are very consistent pushers. Crappy WOT mileage though. I've had mine powering through some very scary 8 foot seas in the San Pedro channel, just driving up the back side of a wave and down the front like it was nothing more than rolling hills. Apparently it wasn't nearly as much fun if you weren't on the helm

i bet you have forearms like Popeye!

bringing my back along the East coast of Hong Kong, the Sai Kung area is wide open to the South China Sea all the way to Taiwan, and I spent 6+ hours at the helm doing an impersonation of the driver in those 1960's Cops & Robbers films, forevere steering right then correcting left then right again then left then (you get the picture)

I have always used knots for navigation, but I haven't changed my new gps from mph to knots,MPH seems like I am scooting away from the Knot Heads.
Ya right, a pycoligic reason for fast is good. Even doing 35 knots in a Cat 40 today seems good.
I just need to slow down, smell the roses and take the site as it apears before I forget.
Slow down to a Galup, what my Uncle told me as a kid.
Dave

Maybe it,s for old folks that can't keep up.

frede wrote:

DaveB wrote:... I wanted a 10 pitch but they don't make it in a 11.8 dia. 4 blade prop...

iBoats list a Michigan Wheel 4 x 12 x 10 for the Honda 50, sounds like that might be the ticket, although the girlfriend does like to go fast, so I don't want to drop speed This weekend I hit 16 knots @ 5000rpm (WOT) with the current 3 blade, GPS speedo, 2 people, no ballast, 12.3 knots max, on the way back. I think I'll change the GPS to MPH, it'll make me go faster

Found the prop in the surveyor's notes:

3-blade 298x254 (11.75 x 10)

that's pretty much the same prop as I am swinging on my BF50 fuel injected Honda; it hits 6,000 WOT and the best I see is in the 16 - 17 knot range. I have a larger 13 inch pitch but haven't tried fitting it

magnetic wrote:that's pretty much the same prop as I am swinging on my BF50 fuel injected Honda; it hits 6,000 WOT and the best I see is in the 16 - 17 knot range. I have a larger 13 inch pitch but haven't tried fitting it

Hm. So I wonder what the real cause is of my lame 9 knot top speed...
10 year old motor?

is the bottom clean? Even small amounts of crud slows me down immensely

also, because the BF50 is in truth no more than a remapped 40hp, the difference between Hull Speed and 2 x Hull Speed is pretty marginal - if you can't develop the torque to get up on the plane because the revs are low, you will stay pitched in your own stern wave. however, once you pop up on top, the increase in revs and SOG is very rapid

I hate the Honda BF50 with a vengeance

magnetic wrote:is the bottom clean? Even small amounts of crud slows me down immensely

Nope. Quite clean.

magnetic wrote: I hate the Honda BF50 with a vengeance

Now you tell me... where were you 3 hours ago (http://www.macgregorsailors.com/forum/v ... =9&t=18464)...