Prop for a Larson Senza 206 5.0 GXI

nootso

Cadet
Joined
Jun 22, 2010
Messages
12
Looking for any suggestions on a good all round prop for my Senza 206.. I'm currently running the stock aluminum 21 X 14.3 3 blade and want to get into a SS 3 or 4 blade.. Here are my stats..

1. Year, make and model of boat
2006 Larson Senza 206
2. Length, width and base weight of boat, look for boat decal on back of boat
20?6? long with a width of 8?3? and the weight is 3150lb dry
2a.What is the maximum recommended HP for your boat
270HP
3. Number of people and gallons of gas normally on boat and what do you use the boat for
Two adults and one child.. 20 gallons of gas usually.. The boat is used for cruising, tubing and wakeboarding
4. Year, make. manufacturer and model of motor and recommended Wide Open Throttle (WOT) range
2006 Volvo Penta 5.0 GXI, SX drive.. WOT is 4600 to 5000 RPM
5. HP and gear ratio of motor IMPORTANT
270HP.. Gear ratio is 1.6
6. N/A
7. WOT RPM and speed from your current prop and how much gas and how many people were in the boat for the test data and is the speed by GPS.
RPM: 4600.. Speed: 54MPH via GPS.. Number of people: 2 adults, one child.. Amount of fuel: 20 Gal
8. Make, model, diameter, pitch, number of blades and whether SS or aluminum prop and does it have a hydrafoil, dolefin or trim tabs
Volvo Penta 21 X 14.3 aluminum 3 blade.. No hydrafoil, dolefin or trim tabs
9. Has your motor been tuned up lately and have you checked that the carburetor butterfly is opening all the way by just pushing the throttle at the helm and not at the carburetor, checked compression, and looked at the plugs and checked spark as well as timing and advance, all of the foregoing could be the reason your prop is not attaining full RPM
Motor is tuned and checked out good.. It only has 60 hours..
10. What problems are you trying to cure or what are you looking for the boat to do that it is not doing the way you think it should or to your expectations and does the prop show any damage that you can see
The current prop is in perfect shape.. I?d like to get the motor up to it?s max RPM at WOT.. A better hole shot would be nice but don?t want to sacrifice to much top end.. I want to go SS and I was going to order a 19P Stiletto Advantage II (three blade) but then started reading about the four blade props like the Stiletto BAY PRO II.. I just want the best all around performance out of the boat..
 

Tail_Gunner

Admiral
Joined
Jan 13, 2006
Messages
6,237
Re: Prop for a Larson Senza 206 5.0 GXI

I think your selection is dead on..the 3 blade has great bite and the 4 blade has greater mdirange and lower planing speeds...Perhaps 1-2 mph will be lost on the 4 blade ...........85% of your boating will occur below 4500...;)

18 baypro
19 advantage
 

nootso

Cadet
Joined
Jun 22, 2010
Messages
12
Re: Prop for a Larson Senza 206 5.0 GXI

Thanks Tail_Gunner...

If I'm 400 RPM shy of my max RPM at WOT with a 21P aluminum do you think I'll achieve max with the 19P advantage? I've read it's a very aggressive prop.. I guess in a perfect world I'd gain 200 RPM per inch of pitch I drop, therefore getting to my max RPM of 5000 at WOT... Anyone do some testing with a similar setup?
 

Tail_Gunner

Admiral
Joined
Jan 13, 2006
Messages
6,237
Re: Prop for a Larson Senza 206 5.0 GXI

Our boats are very similar...You have mabe 1 more foot of hull and and 300 lbs more weight alng with 50 horsepower to your advantage..The Wellcraft turns a 20 4 blade and a 21 3 blade right to 4950
 

nootso

Cadet
Joined
Jun 22, 2010
Messages
12
Re: Prop for a Larson Senza 206 5.0 GXI

What gear ratio in your Wellcraft.. 1.6?
 

nootso

Cadet
Joined
Jun 22, 2010
Messages
12
Re: Prop for a Larson Senza 206 5.0 GXI

I just ordered the Bay Pro II 4 blade 18P online... I'll post results as soon as I get out on the water with it on the boat... If I'm not happy with it I have the option to exchange it...
 

nootso

Cadet
Joined
Jun 22, 2010
Messages
12
Re: Prop for a Larson Senza 206 5.0 GXI

I received my 18P Stiletto Bay Pro II (four blade) yesterday and installed it.. I can't believe the difference this prop made on my boat... The hole shot was very quick and the boat was up and on plain in half the time.. Mid-range performance is awesome.. I was doing about 30 MPH and punched it.. WOW!! 30 MPH to 53MPH right now? My previous max speed was 54MPH with the stock aluminum.. I managed to get it up to 53MPH but the lake was white capping a little.. The RPM were at 4950 to 5000 RPM at WOT? This is what I was looking for as the recommended WOT for my engine is 4600 to 5000 RPM..
A friend was out in his boat and watched me rocket by and said my boat was right up out of the water.. Handling has greatly improved as well.. I?m very happy with the performance of this prop and am glad I did tons of research before jumping into a three blade? All speeds were obtained via GPS..
 

Tail_Gunner

Admiral
Joined
Jan 13, 2006
Messages
6,237
Re: Prop for a Larson Senza 206 5.0 GXI

I received my 18P Stiletto Bay Pro II (four blade) yesterday and installed it.. I can't believe the difference this prop made on my boat... The hole shot was very quick and the boat was up and on plain in half the time.. Mid-range performance is awesome.. I was doing about 30 MPH and punched it.. WOW!! 30 MPH to 53MPH right now? My previous max speed was 54MPH with the stock aluminum.. I managed to get it up to 53MPH but the lake was white capping a little.. The RPM were at 4950 to 5000 RPM at WOT? This is what I was looking for as the recommended WOT for my engine is 4600 to 5000 RPM..
A friend was out in his boat and watched me rocket by and said my boat was right up out of the water.. Handling has greatly improved as well.. I?m very happy with the performance of this prop and am glad I did tons of research before jumping into a three blade? All speeds were obtained via GPS..

Question was this demo done with people or were you going solo...did you notice that your boat road higher and your wake...did it go straight out back or off to the sides.....One last thing..did you ever hear a small hestitaion at the top of the rpm band..just a nano second

:confused: can you recheck your Gears somethings a foot..:D
 

nootso

Cadet
Joined
Jun 22, 2010
Messages
12
Re: Prop for a Larson Senza 206 5.0 GXI

Me and my wife were on the boat... Same load as usual less my daughter (40lbs).. The boat did seem higher out of the water but I wasn't paying attention to the wake.. I don't think the rev limiter was kicking in but I'll listen closer this weekend.. I'll also have a closer look at the wake..

I double checked the gear ratio and it's 1.6... What do you think is a miss?
 

Tail_Gunner

Admiral
Joined
Jan 13, 2006
Messages
6,237
Re: Prop for a Larson Senza 206 5.0 GXI

Your tach...With the alum you show a 2% slip and the ss shows 0....It maybe just splitting hairs..But it is what it is.Hmmm maybe the gps
 

nootso

Cadet
Joined
Jun 22, 2010
Messages
12
Re: Prop for a Larson Senza 206 5.0 GXI

I'm going to use a freinds GPS this weekend and recheck all the numbers with the new prop installed...
 
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