I have a 2007 21V and i had it doing 40 mph yesterday at around 5000 Rpms. I have a 4 blade powertech prop on a etec 150 with the jack plate on 2 1/2 and the trim at 8 on the icommand gauge. There were two of us on the boat and about 50 gallons of fuel.

 

It is either a 15 or 17 pitch prop

 

i'm going to take the prop to a shop tomorrow and have them tell me what the pitch and diameter are.
I'm also going to check the fuel filter and make sure it's not clogged. Even if it is a 21 pitch, i would think the motor could turn it to some high rpm's?

 

what's the highest that you've found you can run your jackplate without the hull sticking?

Is 2.5 the heighth you normally run as a safety factor? Or have you found that's the ideal performance height?

Thanks for your help and info!

 

I usally try and stay in the 2 to 3 range on the jack plate in good conditions and the 1 to 2 range in choppy conditions. I feel i get the best performance and fuel economy at around 2.5 and 8 on the trim. I had the boat down in Grand Isle, La a few weeks ago and had to run in about a foot of water through some flats and the boat ran good in the 4 to 4.5 range on the jack. It will run ok in the 5 to 5.5 range for short distances but the engine gets a little too hot if it is there for more than a mile or so and the Icommand gauges start beeping at me.

 

good info, thanks! i don't have the icommand deal on my Honda, so I appreciate the insight. I looked into the fuel economy gauge cluster and it's $800 for the part! too high for my blood. Plus, that's a lot of money i could spend on gas. THanks again.

 

i pulled the prop this morning to take into a shop and determine the pitch, etc... The values were printed on the back of the hub...14.5x17
I also realized that i've got no "alcohol resistant" fuel line, so I need to change that out and, quite possibly, I may have some gunk in my fuel filter, wherever that is. I can't seem to be able to track my fuel line once it is through the couling (it's buried under a bunch of plastic!). I'm taking the boat to a Honda service guy so he can plug it in, and point out where the fuel filter is.


Bottomline, i think this prop is what most would be running. I've included a picture for comments. The blades look more like knives than paddles. What's the purpose for that? Does anyone suggest going to paddles?

 

Wes here from Shallow Sport,

The Coastal prop you have on the boat is the right design for optimal performance on the boat. That prop runs about $600 new from Chris over at Coastal Props in Corpus Christi. 17 pitch sounds right but if you can't achieve 6000 rpms you may need to drop it down to a 15 or 16 pitch. It is very important that you are properly trimming the motor. You will want to trim the motor to the point that the bow raised out of the water completely. If the bow starts to bob or porpose on you, trim it down a few clicks til it stops, thats a good indication of being timmed properly.

You will also want to have the jack plate up at around 2-3 inches to make sure you are not dragging excess motor through the water. You should be able to get anywhere between 40-45mph with the 150hp on the 21v Shallow Sport.

You can call me or Kyra, or Travis at the office if you have any additional questions-956-233-9489.

Hope this helps. See you on the water.

Sincerely,
Wes Hudson
Shallow Sport Boats
www.shallowsportboats.com

 

Good luck I did all the recomended BLA BLA with what it should be and I ended up way off what they said but I got it nailed now I went from my suggested 14.15 x17 at 4200 rpms to 5000 rpms with a 14x17 now I turned it down to a 16 and bingo 5600!

 

Thanks for all the info and advice. I took the boat to the Honda guy to run the computer check before I start changing out props, because I think that even if I'm a pitch or two off, I should be able to turn more than 3800-4000 rpm. We'll see. I'll post to let everyone know.

paragod, what boat/motor combo are you running?

 

21 ft Dargel 210 Fisherman with a 175 Ocean pro CMC Jack Plate and Shallow Blaster I took it out today on the lake and my hole shot is B@@ A**

 

I have a 225 Honda on a 20' Attackaflat. I have use one of two props for the most part, both are the same style as yours (Clever). One is a 14.5 inch 17 pitch with a fare amount of cup, at WOT it will turn 5500 and run around 43-44mph. The other is a 14.75 inch 17 pitch with more defined clever tips and not as much cup, at WOT it will turn 6200 and run 49-50mph. Both have a good hole shot (boat has trim tabs), the slower one is a little thicker at the tips, and with a little wear it should be a little faster.

Wish I new the brands, but both were used. Atuually bought the second for $100 just to have a spare, and tried it just for fun one day and run it all the time now.

Hope the ifo helps.

 

So apparently the Honda guy hooked up my motor to the computer and, for whatever reason, put on his 14.5x17 3 blade (remember mine has the same numbers, but a 4 blade clever) and on the computer he is reading 6000rpm. Well of course one of the plugs blew so that's another $100. Anyway, he said the tach was reading 4000rpm, which is what I was experiencing...which would mean mine was turning about the same rpm too...
So he's changing the plugs, will put my prop back on an run it again to determine if my blade will turn 6000rpm (as I think it will, based on what he's telling me). So apparently my tach is bad...by 2000rpm or so!
All that said, that means that if my motor was turning 6000rpm on my prop too, and I was only getting 32 mph out of it, that my prop is pitched weird? I'll know final results this afternoon, but that's what I'm interpreting.

 

new test confirms the tach is bad. The motor is actually turning 5700-5800 rpm (tach shows 3800 rpm or so) and running around 37 mph. Of course, I had the GPS reading in knots, not mph, so I thought it was 32mph when it was actually 32 knots.

 

so i guess the next question is...Do I want to be able to get the motor up to 6000 rpm or so? That would be dropping to a 16 pitch 4 blade, maybe that 15. THat being the case, what will my hole shot be? Better or worse? What about fuel economy? Better or worse?

 

Wes! What can you tell me about the prop in the photos of the 24v's on your website? It's one of the last photos, and the shot is taken of the stern. It's a 4-blade. It looks great.
I'm getting a lot of cavitation even when the motor is at 2" on the jack, and I have a Unifit Shallow Blaster installed.
Thanks!

 

alright, i took my prop to Baumann's and talked to him for 15 minutes or so about what I was looking to achieve and the solutions he might have for me. We de-pitched my 14.25x17 4 blade to a 15 pitch. Then he added a pretty intense gulf coast cup. I took the boat out a couple weeks later with the following results:
Lost one hundred or so RPM
Gained a ton of prop lock....i.e. Before I couldn't hole shot above a 2.5 with my jack plate w/o blowing out. Now I can hole shot at the full 6", although I can't run like that because the motor doesn't get fed much water at that height.
Called Louie, told him my RPM issue and we discussed what to do (along with my pro's and con's of the performance). Brought it back to him.
He removed some of the diameter (maybe a .25", didn't measure) and took a bit of the cupping out. Took it out this last weekend and with 4 men in the boat I was able to hit 6000rpm at one point (though consistently 5800 rpm) and can still get up with the jack plate at 6", although there's a bit more slip.
Very happy. Thanks Louie!

 

Good to hear -thanks for sharing the prop details.