Props again, sorry! Suzuki DF50.

[Kloppi74]

Inherited a 26x with a 2001 DF50 from my father. It needs a new propeller but I have no idea where to start. Went to a prop shop with the old one and they said they have nothing similar and it looked like it was from a work boat. I have no idea. It is rather big and has been good but should now be replaced. Would you be able to give specs for a good all around prop? Please.

[Tomfoolery]

From some inner web searching, that engine has either a 6300 or 6500 rpm max rated engine speed with a 2.27:1 drive ratio. That gives a prop shaft speed of 2775 rpm at 6300 engine rpm or 2863 prop rpm at 6500 rpm engine speed.

My Honda Bf50 has a max engine speed of 6000 rpm and with the 2.09:1 reduction, a prop speed of 2871 rpm, which is obviously a little higher than the Suzuki. Most folks with a 26X and the Honda BF50 are using an 11.8” dia x 10” pitch x 3-blade prop.

Suzuki recommends, among many others, an 11.5 x 9, 10, and 11” dia 3-blade props. Since they’re a little smaller and a little slower (but not by much), I would probably start with the 11” pitch and work up or down from there.

The 11.8 x 10 x 3 prop on my X allows almost redline with no ballast, so that’s where I’m coming from. If your needs are different then you will need to adjust up or down (maybe 9” or 10” pitch if you’ll always have ballast in even when going fast so you don’t lug the engine).

Phew - that’s hard to key on a phone.

[Tomfoolery]

Oh, and not all props are the same even if the diameter and pitch are the same. Things like cup, and blade shape, and some other stuff will effect its performance. But first-hand experience with your engine and boat model would be best, so do be patient and wait for someone who has your combo to chime in.

Or find a prop shop that will let you try a couple of props before buying, or allow exchanges until you get it right.

[rszobel]

I have same engine and had to replace prop a few years back. I will take a look at the box from the prop which has the info on it. will try to get to it tonight if possible.

[solarfry]

Don't knock yourself out. Go to the mfgr. Mfgr shows a wide range of sizes in props:

http://www.suzukimarine.com/~/media/Mar ... s_PDF.ashx

[Russ]

I would call BWY
http://www.bwyachts.com/

The prop is not the same as on a standard power boat. I think it's more like a pontoon boat prop.

I've gone through a couple ofprops to get the right size. Just call 'em and ask what you should use.



--Russ

[Kloppi74]

Thank you all very much for the very informative replies!!! they are well appreciated.

In meanwhile I got a chance to try a http://www.propulse.se propeller. With the lowest pitch setting (whatever that is) it makes ~6200 rpm and 14-15 knots (17 mph) with the boat empty but the mast up. I guess that is not very good?
I will normally power the boat very light so I guess I should try something else. I live in Finland and bwyachts is 10 hours away timezone wise. Will try to make them a call today and see what they say. All the info provided by tomfooley sure helps a lot in choosing!! it was also good background info for me new to propellers.

All additional info obviously welcome. Great if rszobel or someone else with the same motor can comment their propeller specs, ideally even together with the performance they get!!

I will report how the choosing goes, specs I end up with etc for the records.

Thank you!!

[Tomfoolery]

In meanwhile I got a chance to try a http://www.propulse.se propeller. With the lowest pitch setting (whatever that is) it makes ~6200 rpm and 14-15 knots (17 mph) with the boat empty but the mast up. I guess that is not very good?
I will normally power the boat very light so I guess I should try something else.

That's very good, assuming your redline is 6300 rpm and not 6000 rpm. If redline is actually 6000 rpm, you're overpropped, and need a little more pitch.

That's about the best mine will do, with no mast and no ballast and a dirty painted bottom. And I just tried it the other day, in fact, so it's fresh in my head. You might be able to get a little more speed if the bottom waxed and not painted, but I wouldn't think it would be much.

50 hp [37 kW] is all you have to work with. That's shaft power, measured at the propeller shaft, so all 50 hp/37 kW OBs do the same thing at rated speed, though the propeller speed and design diameter may not be the same, and therefore require different props to get the max power of the engine into the water in an efficient way.

I think your boat is doing about its best with that engine. If you want to go faster, get a bigger outboard.

Oh, and a three-blade may be a little more efficient than a 4-blade, but again, you're already at or around the max you can realistically expect from that boat with a 50, so any gains beyond what you have would at best be small.

[mallardjusted]

17 mph sounds about right. I had a Suzie 50 on my 2001X up until 4 years ago, and that was my top speed. But, now with my Yammie 70 my top is 22!

[Russ]

Suzuki chart WOT RPM
DF 50
1999-2009
5900-6500


DF 50A
2010~
5300-6300

So you are just about spot on. Speed is pretty good. These boats don't go as fast as the advertisment.

---Russ

[Kloppi74]

Thanks for the additional info!

Called bwyachts too but no luck so dropped a line. They recommended 11 pitch but did not comment the diameter. I take it they mean 11,5 as that is the only 11 pitch I see on the Suzuki tables. I asked to confirm but no answer at least yet. If you have clear idea please comment.

As I wrote I am new to these things so almost surprised that I can choose from the std suzuki selection for this very special boat. That is because the old, original propeller which apparently worked well was clearly different. It had larger diameter but smaller pitch.

I can keep the propulse propeller for now so will do it for now as it is good but will the most likely install an aluminum rotor later. the biggest reason being the composite propeller appears very vulnerable and it is already adjusted to the max so have no additional benefits of it being adjustable. Might even repair the old rotor. Will post here for the records. Thanks again you all! additional comments obviously welcome. I am very glad I found this site!! Loads of good stuff here

[Ezra_BWY]

For the 26X and a DF50 we have two different recommendations, depending primarily on how heavily the boat is weighted.

With a normally weighted boat, with bottom paint, we would go with a 10 pitch, 11 1/2" diameter. Suzuki part number: 58100-88L13-019

With a very lightly weighted boat, with no bottom paint, we would do 11 pitch, 11 1/2" diameter. Suzuki part number: 58100-88LA0-019

[Tiger]

Very interesting and useful information. Thank. But can there be a recommendation on 26M, DF60ATL? Thank you again.

[Ezra_BWY]

Hello,

For the 26M and DF60ATL combination we recommend the 11 5/8" x 12 pitch prop. That is Suzuki part number: 58100-88LA0-019

Note that the Suzuki part numbers I listed are the "original' part numbers, sometimes Suzuki supersedes part numbers when they make a change to the packaging or a change on their end in manufacturing plant or something, so if you can't find those part numbers it will take a little bit of digging to find the current number.

[rszobel]

I have same engine and had to replace prop a few years back. I will take a look at the box from the prop which has the info on it. will try to get to it tonight if possible.

Just checked it out - was stowed away in the attic! i have an 11 pitch - 11.5 diameter. Number is: 5811-95222-019. based on another recent post, my boat is lightly loaded and could have gone with the 11 1/2. hope this helps.