Suzuki DF150 propeller

[jayw]

Marcus at Power Tech spent about 20 mins. on the phone with me. He's the one who recommended the OFS and I think it was a great rec. Has a lot of blade area and good cup which I think helps give it the bite the DF150 needs. I was reluctant to go 4 blade in part because of the additional stern lift which I feared could lead to less bite. Also I do think we'd lose a bit at the top. Even though it's not a fast boat by power boat standards, every MPH at the top end is still precious.

I also forgot to mention it seems smoother than the AL prop too at cruising speeds. We dropped pitch 2", went up 1" in diameter, and gained top end. Some guys were guessing we'd accomplish nothing as other prop shops I spoke with said the diameter isn't a factor. Not sure why they said/believe that but that's just not true. Mercury makes good props but I don't think you could find someone at Merc to spend 20 mins on the phone covering our specific application. I personally think pontoons are not as easy to prop as planing hull boats.

Though this thing stands up tall out of the water once you get up to about 25, and by 30 I think only about 1/3 of the toons are still in the water. Get so high up you almost feel like you're on a small cruiser.

I duuno, maybe if I get the itch next spring I'll send it back to JC for the strakes. That should squeeze another 5 MPH. Maybe 7.

[jayw]

OK so there's more to this story...

I ran the prop several more times and with different loads too. I found a couple things:

1) I may have slightly overreported RPMs @ WOT. With me and my wife its more like 5700/5800. Then on July 3 we had 2 more adults, 2 kids, 80 lbs in coolers and their extra gear on board and could barely make 5500. RPMs fell off too fast considering 4 adults and 2 kids isn't half the boats rated load. What will happen when we take out 6 people?

the 19P was right on the edge I felt, with me & my wife. After talking it over with Ken @ PropGods and the guys @ PowerTech I decided the best thing to do was to go to the 18P. I can report back the results after I run the 18P.

Again conventional thinking says we'll lose top end but I don't think so, I think top end will be a wash with the extra 200RPM making up the lost MPH but the engine won't work quite as hard and will be able to pull a larger load a little better. I know it's splitting hairs a bit over 1" of pitch but I think it'll be worth it. If I can get it right on the mark with me & my wife, that'd be a great baseline for other loads on the boat.

2) I had to run the old 14.25x21 AL prop a couple times as I wait for the new prop to get here. I got another chance to really feel the difference. Just like I said, it's significant. The SS makes a night-and-day difference in every regard. Fuel economy being one of the biggest diffs I think, which to us is big. [overall I could be happier with the fuel economy of this DF150 but that's a story for another time]

Hoping the 18P is the very last one I need.

[dockholiday]

How is the prop gods working the exchange? I thought the 19 was a bunch of prop for a 150 but just figured there were other factors diff than the props I first tried. I couldn't even turn a 17p mirage plus over 5300. Stay on it the right ones out there. I would probably be better with the 16 enertia but not worth the change.

doc

[Bmac]

Doc,those zuki's are geared pretty low. They can sling those tall props. I'll be hunting a prop for mine soon. Thinking about a enertia. Are the prop Doc's able to work with the new alloy? I like buying one pitch under then add cup where I want it.

[dockholiday]

Think the 16 enertia is where you want to be. I believe Carl started with the 15 enertia an later changed to the 16 with his 150.
doc

[jayw]

For the exchange I had to ship the old one to PowerTech @ my expense, then pay the exchange fee and shipping on the new one which comes to about $70 total I think. So while it's worth it, it's not something I want to keep doing if I can avoid it. I'm hoping the 18P is spot on.

I know the exchange deal works differently with Merc, I would have had to ship out to Prop Gods for the Merc and not direct to factory.

Yes the DF150 is geared 2.50:1 so it can turn a big prop. the 14.25 AL I have is a 21P but of course, it has so little bite over 5000rpm that a lot of the increase between 5k-6k translates into little more than fuel waste. The PowerTech OFS has a ton of bite, with a lot of cup and blade area thus reducing the pitch I can run.

I could have kept the 19P, a lot of people would have I suppose, but for the $400 prop I want it as near perfect as possible.

The JC U-toons give a ton of lift, even w/o strakes, so you really rise a lot out of the water. This is where the larger diam prop favors my boat/engine setup I think.

Anyone running a 4 blade Turning Point AL? I was thinking about buying one of those for $100, for kicks, and seeing if it gave me better cruising under greater load. I can't seem to find those any more though.

[bjammin502]

Jayw I think we are living parallel lives as I am in the process of duplicating everything you have just gone through. I just bought a 2011 Bennington 2275 RCWLTD TT with a Suzuki DF175 that came from my dealer with a Suzuki SS 3x15.25x19 which isn't doing a very good job handling a load. I have been researching this to death and I now know more than my dealer which is another story in itself. Personally I think these dealers need to be more educated or solicit true experts when it comes to prop selection. I am a little frustrated that I just dropped a ton of cash on this boat with the expectation the dealer was an expert and would get everything right all the way down to the prop, well not the case. Now, my extensive research has also pointed mr to Power Tech props and I have spent quite a bit of time talking with Marcus and these guys are truly the experts. I am impressed and believe me I don't impress easily. Marcus is recommending the OFS 4 blade 15.25x17 for my setup. One thing that is different on my approach is trying to optimize my loaded/typical condition. Being a pontoon we rarely just have two people on board and once loaded the 3 blade can't carry the load. My mid range performance numbers are terrible eventhough I am turining 6100 and 40 mph but only in a light condition. I have determined there are two schools of thought: prop light to reach rev limiter or prop under typical load and stay out of the throttle when light, the latter is correct IMO. Now, this all said prop selection is very personal so to me the most important area is what we spend most of our time doing which is cruising. I may give up a few mph on top end and if I do I don't care as long as my load carrying gets better. There is a strong chance my numbers will improve due to an increase in efficiency. I haven't order the new prop yet but I hope to tomorrow, got to get the wife on board to spend more money on the boat but not until I try to work something out with my dealer.

So if anyone thinks my brandnew Suzuki prop is the correct setup for them, please contact me and we can work out a deal.

Thanks

[jayw]

Hi, sorry for the delay in posting but I wanted to have at least a bit of info before coming back.

I got the 18P installed, and it was nearly a textbook swap. Under typical load I gained about 250-300 RPM (more than the rule-of-thumb 200, but the guys @ PowerTech estimated this correctly). We MAY have lost 1/2 MPH at the top of the throttle. Otherwise everything just moved up the tach a couple hundred revs. We still have a great holeshot (the PowerTech 19 was equally impressive). But I can't report anything under load since we haven't had any guests aboard.

Next week we're planning to have 3 adults, 3 teens and 2 kids so we'll see how it goes then. The more I think about this whole thing the more I think, the 4 blade is probably something I'll buy at the start of next season. I'll probably go with the OFS4R18, and see how that goes - then decide if I need to swap for the 17. I'll keep the 3x18 as well, and swap them around.

Hey bjammin can you tell me if you have strakes? The strakes help at the top of the throttle, and not having them - despite the great lift I think these utoons have - is robbing me of 3-5 MPH, as a guess. I may add them next yr, it's an expensive proposition but I may. Unless I decide that the top end just isn't worth it, I rarely go there anyway. I'm usually cruising at 25-32 MPH when we're crossing a lake or something.

bjammin definitely let me know if the 4 blade gives you what you want. How do you like the Bennington? I like our JC, very stylish, but there are a few areas where I think improvement could be made.

[dockholiday]

bjam, agree one hundred percent about the dealers and their selection of props. Think some time they know it's the wrong prop for the boat but have one left over from an exchange and just put it on to get rid of their surplus.
Sad thing is many new owners never know it wrong and they stay on there until someone point it out or they trade the boat. Glad you guys are going for the gusto and maximizing your performance
doc

[jayw]

So I know this is late on this post but... I'm updating in case anyone is interested or reads this in the future for their own purposes.

After a summer of putting the JC Neptoon 21TT/Suzuki DF150 through its paces, I can say unequivocally that the Power Tech OFS 3 blade 15.25x18x3 is the right prop. We ran different loads all summer, and the prop did great. We took my sister's whole family out (6 people, incl 4 adults) and with 30 gals gas and 2 huge coolers plus all their gear and snacks and we still got 31+ MPH out of the boat. With me alone and less than 25 gals gas, I can run 38. We have no strakes. I think the 19P would run to 39, but this is really perfect for us. My wife and I, with our gear and a loaded cooler, run 36 @ 6K RPM dead on. That's in a light to moderate chop, 1+', with a 15 knot headwind.

We're stopping here and not chasing the rainbow any further. I'm not adding the strakes. We have incredible lift with the 3 u-toons. The boat actually planes. You feel the hull rise - a lot- as you power up. Look over the side at 30MPH from the captains chair and you're several feet off the water line. I've never seen the boat underway from anywhere other than the helm but based on the looks we get CONSTANTLY from people as we pass, it's gotta be a cool and interesting sight, if nothing else. People watch us cruise by all the time. They pay no attention to the Formulas going by at 50+, but us - they watch.

We rented a Manitou on a family weekend away. It was a 2 logger with a Merc 90 and holy crap, I almost forgot! That boat labors, you can feel the pontoons create more and more drag as the engine revs up. Our JC, the more power - the *less* drag.

Nope, ours isn't the fastest pontoon on the lakes - but one of the best looking IMO and a lot sportier than most all the other pontoons. We've got lots of I/O toons that rumble along our lakes at 40+ MPH, sucking tons of fuel. We put 100 hrs on the motor this season, as of Sept 20, and never did we burn more than about 12 gals in a day - and that was a full day with lots of WOT and a full load of passengers.

Yeah, that's a prop I would recommend to anyone running a heavy toon with a df150 or df175. It was worth the hassle of all the legwork, exchanges, etc.

[jayw]

2 yrs later and here's a follow up post. It's worth the bump.

That prop was serving me so well that when we had the boat at the welder to fix toon damage done by the marina I decided to have him tweak the prop to nudge the top end a bit (welder happens to be the owner of one of the very best prop shops in the region and is well respected and recognized for his talents and experience). I was convinced that I could gain 1-2 MPG top end with his magical touch. He labbed the prop to shave some weight and added a hair of cup.

If it ain't broke don't fix it.

This resulted in a reduction of RPM range by a couple hundred RPM to 5800 (I can trim it up to goose it a little but it seems to gain me little benefit, except blowout on turns). Net effect is, a loss of about 1/2 MPH top end. So either I have him re-tweak it, leave it be (we'll see what happens with a load of people, IF we ever get summer weather again in the Midwest!) or buy another prop and ebay ths one.

Moral of the story: that prop, just as it comes out of the box, looks to be optimal for my boat. Wish I had left it alone. And it cost $200 for the work!

[jayw]

So I had the prop tweaked again by the prop guy, he improved it but now it's got other issues. It can't handle the big water like it could before, and we get tossed around in a chop. We aren't getting the lift. And we can't get on top of the water. Loss of power under weight load. And in the chop, forget it. We lost some top end speed, which means I can't get the ride smooth. Not good.

In ideal conditions it's OK, but ideal conditions by us are rare. We are usually fighting a chop from the big cruisers and 30' speedboats stirring up the shallow waters.

I don't think there's much I can do but buy a new one and learn one very pricey lesson, keeping this one as a spare.

[bjammin502]

I am sorry I never got on here to give all an update. So I tried the four blade prop which did a pretty good job but someone who was very familiar with Suzuki engines suggested that I try 3 blade 16" prop; the 175 has same lower unit as the 225 and 250 so can spin larger props. After trying both I decided the three blade 16" had slightly better numbers. One challenge with a four blade is it lifts the stern instead of the bow which makes cutting through chop worse. It's funny you asked me about this thread now because I just spent the weekend with the largest crowd to date (12 people)....boy you can certainly tell the boat was loaded but I am not sure another prop would have done any better. I wasn't able to plane as easily as I normally do but at 4100 to 4200 rpm I was able to get the bow up to cut through some large waves. I tried one time at full throttle and my max speed was about 28 mph (kind of slow but this was 12 large adults....no kids) and I want to say my rpm was around 5600 or so.

I will dig out my spread sheet and post it. I am sorry you are having prop troubles but hopefully this info will help. Click on this link to see my spreadsheet test https://www.dropbox.com/s/v0d31trm7yll9 ... rTest.xlsx

[jayw]

Nice chart bjammin, thanks. What's the left margin scale? How much gas do you hold?

I'm not sure the Suzuki props are the best SS on the market, I would love to have seen that same PowerTech config installed. Bet your numbers would be different.

And 16" prop... may be worth a shot (I think the biggest mistake people make with the Suzukis 150+ is they try to spin too small a prop). The DF150 will spin that 16" prop too, but I bet I'd need to drop from 18P to 16P to compensate. the PowerTech is a 15.25, that extra .75" makes a huge surface area diff. And in terms of maximizing leaf surface area, a 3x16 might be a good compromise for us, as opposed to that 4 blade - which may respond as you said with the extra stern lift. You NEED that bow up to properly break the waves. But in theory, a 4 blade with a good trailing edge cup should be able to provide bowrise too.

Excuse the dumb question bjammin, did you play with the trim with the 4 blade? Did it make much diff?