Parker 2520 performance with Yamaha F250

[DaleH]

The new High HP ones have them 5/8in apart ...

Really, new ones are spaced on 5/8" centers? What's that leave, a web of maybe 1/10" between holes?

 

[warthog5]

I wished I had got a pix today of that Dale. They told me that Suzzy also wants at least 6 bolts in the motor.

Now I would of had a little dought at that statement initially, but [again didn't get a close pix] They have no slot on the lower bolts. It's All drilled. Top holes and bottom holes. You guys know that these Stainless Marine brackets have 2 holes drilled at the top of the bracket. That is unusual as far as brackets go. Most just have the standard pattern and 4 holes drilled.

But here is the other thing. There were Special Flat washers installed on the forward side of the bracket. These washers had 2 holes in them. IE: Spaced to match the 2 top holes.


But Hmmmmmmmm! Now that I think of it. That would not work if the spacing was 5/8in. between holes.

I'm gonna have to dig in this deeper.

 

[BradH]

Brad H - here are the numbers for both props with Slip calculated. Ken from prop gods was good enough to provide slip calcs for me, which I was ignorant of. He also suggested a 4 blade prop (Powertech OFS4R16 15 1/4 X 16) or adding cup to my existing 15 1/14 X 17 and he was not convinced the 19" prop I became so enamored with was the better choice. By the feel of how it blows out on turns, I can imagine the 19" blowing out frequently running in 3' sea. I can normally run no more than 25-30mph comfortably, I am looking for the best economy in this range, not top end speed. I will look more closely for the maker of the 19" prop, it is quite old a bit rusted and appears to have been worked on a bit. The 17" prop is made by Honda.

Sounds like you are on the right track with Ken. I am very interested to see the numbers with the 4bl. Lots of people have had good results working with him. I think stepping down in pitch and going to a 4blade is a good way to go.

From the PowerTech website on the OFS4-
15.25" DIAMETER, AVAILABLE IN 14"-28" IN PITCH, 4 BLADES, RIGHT- AND LEFT-HAND ROTATION, MODERATELY HIGH RAKE AND FULL TIP CUP FOR EXCELLENT LIFT AND GRIP, GOOD FOR SINGLE- AND TWIN-ENGINE OFFSHORE APPLICATIONS AND STERNDRIVES - POLISHED FINISH ONLY

Power Tech makes a decent prop. However, some of theirs are knock offs of other peoples wheels- Yam, Merc, Solas, etc. For example, the 3 blade SS PT I have is a really crappy knock off of a stock 3bl aluminum Yamaha wheel. They could have done so much with it by just thinning it out a little and actually using the increased strength of the SS compared to what they needed with Al. The thing sucks but I don't have the $$ to be playing with props the right way right now.

If the 19 was worked on, I doubt it's still a real 19. It may never have been a 19". Some of the stock Merc Bravo props are like this.

Also, adding cup to a prop sometimes makes it seem like it has more pitch. So the 16 he's proposing may act like an 17-18". Which is not a bad thing at all.

Do you have 46-5800 numbers for the 19" wheel? I was looking at slip too.

Big thing to remember with props and testing them...there is no substitute for going out and actually running the boat and finding out what works and taking notes on it. The pitch number stamped on it is not always accurate, and is really best used when comparing wheels of same make and model. Rake and cup are a lot harder to define, and not everybody does it the same way, or even knows how. What you get is an apparent or effective pitch that has been affected by both of these. #of blades and blade area has a lot to do with it too.

 

[BradH]

I'm really surprised more people don't run 4 blades. Does Parker set up any boats from the factory with them?

Each engine manufacturer has them as OEM parts, so I don't think that's the problem.

It's not Parker, it's the dealer and engine Mfg'r. And just because they make a 4-blade prop doesn't mean it's ideal for your rig. And personally I don't even trust ANY dealer to set my boat up the way I need it to perform best.

Less Merc props, which are argueably THE best props made for any boats anywhere (... too they don't make big diameter ones for Suzi motors), IMHO one can always improve on a OEM or stock prop by going to a premium brand. And for the record, again less Merc, the OB companies don't make their own labeled props anyway.

Boat set up is almost an art, very few people really know what they are doing. Testing a bunch of props and taking good notes is key. But this takes time and money, even if you're getting test props shipped from somewhere.

Merc makes a good prop. I like using Brett at BBlades because worked in the prop design shop at Merc for years, and knows the products and how to lab them. Yamaha makes their own too, and bought Precision Propeller recently to expand production facilities.

I don't think any company or brand is overall any better than another for an outboard or stern drive prop. It depends on what you're looking for and who has it. With the advent of universal hubs the world got a lot bigger. The hard part is wading through the marketing BS and figuring out the actual design of each prop, how it will affect the boat.

If you're going racing or really hi performance, go Hering. Sportfish and yacht go Veem.

 

[Carborita70]

@ BradH -

Ken gave me these stats from another 2520 (seen below), he did not reveal the HP but it is likely similar. I do not have the $$ to get the 4 blade, so I will have the 15 1/4 X 17 cupped next week; if the weather holds I will be making a 90 mile round trip with this prop (as it is) Sunday & will take notes on economy etc. Then try the cupped version when time allows. I just do not trust the 19" to not blow out with sea/weight as yet. Coming in 45 miles offshore with a blowing prop would stink. Getting this stuff dialed in is so time consuming. When I tested the props I needed to get the boat on the trailer for a quick out & in; the ramp was promptly visited by every mo-tard in the county, had to wait 40 minutes for the cluster f***k to work itself out.


Smooth Conditions.
Little over 1/2 tank of fuel.
2 people.

17 pitch Yamaha black stainless
4000rpm 20mph 2.1mpg
4500rpm 25mph
5000rpm 30mph
5900rpm 40mph

17 pitch Mirage Plus
4000rpm 16mph
4500rpm 27mph
5000rpm 34mph 2.2mpg
6000rpm 40.5mph

17 pitch Revolution 4
4000rpm 22mph 2.0mpg
4500rpm 30mph 2.2mpg
5000rpm 35mph 2.3mpg
5800rpm 40mph

17 pitch Powertech OFS
4000rpm 20mph 1.9mpg
4500rpm 27.5mph 2.2mpg
5000rpm 35mph 2.3mpg
5900rpm 38mph

 

[ceblizzard]

I went with the 17 pitch Rev 4. I couldn't be happier. I'm getting the exact numbers as was stated from Ken at Prop Gods. I'm running a 2010 F250 on my 2520XL.

Charlie
Eden, Md.

 

[BradH]

Sounds like you are set. Let us know how it turns out.

 

[Carborita70]

I made a 42 mile offshore trip into a following 2-3' sea with my non-cupped 15 1/4 X 17 wheel with my motor now raised to 3rd hole. Sea conditions made all the difference as performance was not very good regarding RPM/MPH; with 5000 RPM getting about 25mph. The thing that worried me was the prop fanning a bit when the aft end came up. I knew this would be worse on the way home into a head sea...and it was. The prop fanned at zero trim 100-200rpm when the aft end rasied in the sea. I have not fueled the boat up yet, but I doubt the economy was very good at all. I am not sure if cupping this prop is the way to go, may have to spend that $ and get the 4 blade.

I went with the 17 pitch Rev 4. I couldn't be happier. I'm getting the exact numbers as was stated from Ken at Prop Gods. I'm running a 2010 F250 on my 2520XL.

Charlie
Eden, Md.

Ceblizzard - At what height do you have your motor mounted?