Setting up my DF300 Suzuki props

[knotreel]

This is part 4 or maybe part 5, I forget. Anyway one more change and it looks like I might be done. I have finally got close to solving the riddle of the DF 300's on my custom built boat ,Hammer. Problem was, all tests ended in high speed blow out or ventilation before getting to WOT rpm. Usually the port would go first causing an unsettling port turn. I finally theorized that the full length keel pad was not letting the zukes stay buried as they apparently like. 50mph is the speed where my boat has always leveled itself on the pad making the running trim as low as it will go on this boat. Getting beyond the 50mph "barrier" was the hold up. Not being able to break the 50mph barrier meant no WOT rpm to pitch the props.

After starting off with 16"D Zuke props I finally worked down to 14 1/4". This is contrary to the "zukes like big props" mantra, this was wrong in this instance. They may "like" big props but the smaller D in my case is helping the blow out as is maybe the turbo design. Round ear four blade, that is, at least one of them is?? That's another story.

Other tests that totally sucked are omitted as are the tests done in the fourth hole. All but the last test were in the second hole and last one in the first hole was the charm and glory be! WOT finally achieved FOR THE FIRST TIME!!

As you can see, now that I finally got to see WOT rpm, I have some pitch tweaking to hopefully get 2-3 hundred more rpm. Interestingly I almost gave up on today's test and declared it a failure until I tried trimming the engine way out beyond 40%, bingo!

I have really struggled with this and prop companies told me that no boat bigger than 23 feet or something should have diameters under 15"D and would not listen to the problems I was having. MY friend Bo, at Bo's Propeller in Port Vincent LA got me though all this, thank you Bo, he is one guy that can think out of the box.

The latest slip numbers going all the way down to almost 2% look impossibly low but all I can do is use the pitch stamped on the props. However these numbers may be too low, but they show the trends I was looking for.

Back on the "zukes love big props" mantra, at some point I wondered why not run smaller ones? I am now thinking all the big diameter stuff may have started as part of a Suzuki marketing program which came out when the 300 was the mack daddy big motor, the story was, put these huge 300hp motors on your huge boat with these huge props. I guess they have sold a few more zuke props that way. I say the motor doesn't give a doggy do-do. Yes it can run big props but I don't think it HAS to. Well ,that's my story and I am sticking to it.

Turbo Offshore I 15x24P

rpm mph %slip mpg

3600 32 18.6 1.95

4000 38 13.1 1.9

4500 45 8.5 1.6

4900 50 6.6 1.4

5450 53 11 -

PowerTech OFX 15 1/4X22P

4400 39.5 10.4 1.65

4600 41 11.0 1.58

4900 45 8.3 1.38

5900 52.5 11.2 1.1

Turbo Ultima 4 14 1/4X21P

3500 27 19.3 1.75

4000 36.5 4.0 1.8

4500 40.9 4.9 1.73

5500 50.8 3.4 1.33

"Pair" port Turbo Fusion 14 1/4X 23P starboard Ultima4 14 1/4X23P

motor dropped to 1st hole.

3500 33 10.0% 1.97

4000 40 4.59 1.82

4400 44.4 3.6 1.62

4500 45.6 3.29 1.63

5000 50.9 2.8 1.36

5600 57.4 2.19 1.3 WOT achieved at last!!

My boat is a custom 30' cc that can be checked out on my website knotreel.com

I am thinking with a little less pitch I will finally see close to 60 top end.

Edited September 5, 2009 by knotreel

[got4on]

This is part 4 or maybe part 5, I forget. Anyway one more change and it looks like I might be done. I have finally got close to solving the riddle of the DF 300's on my custom built boat ,Hammer. Problem was, all tests ended in high speed blow out or ventilation before getting to WOT rpm. Usually the port would go first causing an unsettling port turn. I finally theorized that the full length keel pad was not letting the zukes stay buried as they apparently like. 50mph is the speed where my boat has always leveled itself on the pad making the running trim as low as it will go on this boat. Getting beyond the 50mph "barrier" was the hold up. Not being able to break the 50mph barrier meant no WOT rpm to pitch the props.

After starting off with 16"D Zuke props I finally worked down to 14 1/4". This is contrary to the "zukes like big props" mantra, this was wrong in this instance. They may "like" big props but the smaller D in my case is helping the blow out as is maybe the turbo design. Round ear four blade, that is, at least one of them is?? That's another story.

Other tests that totally sucked are omitted as are the tests done in the fourth hole. All but the last test were in the second hole and last one in the first hole was the charm and glory be! WOT finally achieved FOR THE FIRST TIME!!

As you can see, now that I finally got to see WOT rpm, I have some pitch tweaking to hopefully get 2-3 hundred more rpm. Interestingly I almost gave up on today's test and declared it a failure until I tried trimming the engine way out beyond 40%, bingo!

I have really struggled with this and prop companies told me that no boat bigger than 23 feet or something should have diameters under 15"D and would not listen to the problems I was having. MY friend Bo, at Bo's Propeller in Port Vincent LA got me though all this, thank you Bo, he is one guy that can think out of the box.

The latest slip numbers going all the way down to almost 2% look impossibly low but all I can do is use the pitch stamped on the props. However these numbers may be too low, but they show the trends I was looking for.

Back on the "zukes love big props" mantra, at some point I wondered why not run smaller ones? I am now thinking all the big diameter stuff may have started as part of a Suzuki marketing program which came out when the 300 was the mack daddy big motor, the story was, put these huge 300hp motors on your huge boat with these huge props. I guess they have sold a few more zuke props that way. I say the motor doesn't give a doggy do-do. Yes it can run big props but I don't think it HAS to. Well ,that's my story and I am sticking to it.

Turbo Offshore I 15x24P

rpm mph %slip mpg

3600 32 18.6 1.95

4000 38 13.1 1.9

4500 45 8.5 1.6

4900 50 6.6 1.4

5450 53 11 -

PowerTech OFX 15 1/4X22P

4400 39.5 10.4 1.65

4600 41 11.0 1.58

4900 45 8.3 1.38

5900 52.5 11.2 1.1

Turbo Ultima 4 14 1/4X21P

3500 27 19.3 1.75

4000 36.5 4.0 1.8

4500 40.9 4.9 1.73

5500 50.8 3.4 1.33

"Pair" port Turbo Fusion 14 1/4X 23P starboard Ultima4 14 1/4X23P

motor dropped to 1st hole.

3500 33 10.0% 1.97

4000 40 4.59 1.82

4400 44.4 3.6 1.62

4500 45.6 3.29 1.63

5000 50.9 2.8 1.36

5600 57.4 2.19 1.3 WOT achieved at last!!

My boat is a custom 30' cc that can be checked out on my website knotreel.com

I am thinking with a little less pitch I will finally see close to 60 top end.

those motors should turn 6 grand......

[Chisox]

Last time out on our 29 SS, we saw 6300. Looks like that pitch will have to pick you up at least 500 RPM.

[Troutman561]

those motors should turn 6 grand......

I agree.. Did you ever try to Merc Bravo I or Rev 4? I know myself and many others have found great performance with a Bravo I on single and twin set ups.. I had the same problem with blowout in rough seas with the Suzuki props and switched to the Bravo's and it is perfect now.. But yes, optimally you want between 6000-6200 rpms at WOT..

[knotreel]

the bravos were one of the omitted tests, the published tests were just some that had some potential. I was shooting for a prop that did not have as much stern as lift as the rev4 and bravo1. I like the way the present props run except for the obvious pitch issues. But since I own a pile of props now, won't be running out to buy more right now. Plus, I plan a few fishing trips to see how they do with a fishing load in the gulf. Then I will get into the pitch issues. Right now I am just happy to finally be able to run WOT. I plan on shooting for the middle of the 5700-6300 range, say about 6000 light maybe 5700 heavy. I have noticed that the fuel economy above 4500 starts to go off, so I will not shoot for max top speed.

[Chisox]

...so I will not shoot for max top speed.

OMG! Blasphemy! What will Homesite say!!!???

[Drailey]

ya need to get in touch with the prop gods!

[ken2]

Back on the "zukes love big props" mantra, at some point I wondered why not run smaller ones? I am now thinking all the big diameter stuff may have started as part of a Suzuki marketing program which came out when the 300 was the mack daddy big motor, the story was, put these huge 300hp motors on your huge boat with these huge props. I guess they have sold a few more zuke props that way. I say the motor doesn't give a doggy do-do. Yes it can run big props but I don't think it HAS to. Well ,that's my story and I am sticking to it.

I completely agree with your thoughts on "big props"

Its marketing, and its their way of seperating themselves from all the other motors.

They all do it to some degree.

the Verado is a "system"

Etec has "less moving parts" therefore less maintenance

Zuke is geared super low so we can spin a HUGE prop.

Yamaha says "were frickin Yamaha and were awsome.

Its advertising, and thats it.

Certain boats like certain things. Those big 16 inch props actually work very well on certain setups, but not all.

Sounds like your getting the boat dialed in, Good luck

Edited September 22, 2009 by ken2

[knotreel]

I completely agree with your thoughts on "big props"

Its marketing, and its their way of seperating themselves from all the other motors.

They all do it to some degree.

the Verado is a "system"

Etec has "less moving parts" therefore less maintenance

Zuke is geared super low so we can spin a HUGE prop.

Yamaha says "were frickin Yamaha and were awsome.

Its advertising, and thats it.

Certain boats like certain things. Those big 16 inch props actually work very well on certain setups, but not all.

Sounds like your getting the boat dialed in, Good luck

I can't fault Suzuki for using a little HP printer ink sales approach. After all, you shouldn't believe everything the mfg, tells you, oils are one of favorite outboard rants too. Ok, use good oil, even use really good oil, but now use our super exepensive low carbon oil, then add a gas additive like "ring NOT free" so carbon won't stick your rings an destroy your motor and now some dealers are saying use that additive in F strokes. I'll rolling my pant's legs.

Back to the props. There is no question in my mind that zuke has some catching up to do in gearcase shapes, their super sonic missile nose cone shape vs, the rest of OB mfg's that use attack submarine shaped. Enought said. These puppies are picky while others can run pretty good in a range of heights and trims.

After a full load test it now looks like I will be best propped at 21P or 21 1/2 P hummm! that's what my 225 merc's ran only difference is gear ratio, 1.75 to 1 vs 2.10 to 1. That sucks!! I need a minimun of 300 more like 400 more rpm.