Prop under perfoming??

[AngelC]

Hey fellows,

Just got in from lake perris. Went out today with my son to test out the new prop. It was just him and I and a Half of tank of gas. I was running the stock volvo 14.5 x 19 aluminum prop until I scraped it up. So then I went and ordered the exact same size in the Turning Point Legacy and lost Rpm and mph. I don't understand how that could be. I did add trim tabs but if anything I should have gained mph. The trim tabs work Awesome but my over all top end mph is weak. WOT was 46mph at 4100rpm. My engine/boat are rated 4400 to 4800 rpm. I usually have 5 to 7 people aboard with a full tank so that is even going to bogg it down even more. My question to you guys is how can I get into the range of 4800 intead of the 4100rpm I'm running now? What should I do to get my rpm's closer to 4800? The out of hole was excellent and on plane was quick but my top end was a downer. If anyone can give some suggestions I would really appreciate your help!!
Here is the prop that I have on the boat now.

http://www.anchorexpress.com/Turning-Point-Legacy-Propeller-LE-1419-p/le-1419.htm

I have the Volvo Penta Gl 5.0l V-8 305 on a 20'6" Larson boat.

 

[Dhadley]

Re: Prop under perfoming??

Lots of things to consider but the main thing is - not all 19" props are created equal. Then, the tabs. They can indeed slow you down, especially if they are not installed correctly. It almost sounds like you made 2 changes at once - the tabs and a prop. If I were looking at your boat I'd unhook the tabs and test with the new prop.

 

[steelespike]

Re: Prop under perfoming??

What he said^.When making changes allways make one at a time.

 

[AngelC]

Re: Prop under perfoming??

Guys,

I beleive the tabs are installed corectly. I installed them exactly like the instructions say to intall them. Also I am very happy what the results from the tabs; I don't want to remove them to get more top end. Would I get more off the top if I change the pitch of the prop?? if so what size would you say what get me to where I want to be 4800rpm's.

 

[Rocky_Road]

Re: Prop under perfoming??

Hey fellows,

Just got in from lake perris. Went out today with my son to test out the new prop. It was just him and I and a Half of tank of gas. I was running the stock volvo 14.5 x 19 aluminum prop until I scraped it up. So then I went and ordered the exact same size in the Turning Point Legacy and lost Rpm and mph. I don't understand how that could be. I did add trim tabs but if anything I should have gained mph. The trim tabs work Awesome but my over all top end mph is weak. WOT was 46mph at 4100rpm. My engine/boat are rated 4400 to 4800 rpm. I usually have 5 to 7 people aboard with a full tank so that is even going to bogg it down even more. My question to you guys is how can I get into the range of 4800 intead of the 4100rpm I'm running now? What should I do to get my rpm's closer to 4800? The out of hole was excellent and on plane was quick but my top end was a downer. If anyone can give some suggestions I would really appreciate your help!!
Here is the prop that I have on the boat now.

http://www.anchorexpress.com/Turning-Point-Legacy-Propeller-LE-1419-p/le-1419.htm

I have the Volvo Penta Gl 5.0l V-8 305 on a 20'6" Larson boat.

If the Legacy is a progressive pitch design, then the 19" rating is the average pitch across the prop's range. That means the prop has an effective pitch from about 17" to 21"...depending upon the engine speed, and load. You might want to check with the prop manufacturer, and see if you have a progressive pitch design....

 

[AngelC]

Re: Prop under perfoming??

I went on to the manufactuers website and read this.

http://turningpointpropellers.com/

Remember this rule of thumb: For every 2" of propeller pitch, rpm's will change approximately 400 rpm's. As you drop in pitch, rpm's increase, and as you go up in pitch, rpm's decrease. So if we want to raise our rpm's we should choose a lower pitch prop. Following the rule, going down to a 19 pitch should raise our rpm's to about 5300. That would help the hole shot and also gain us some more speed.

I'm at 19"pitch now at 4100rpm, If I get a 17" it should put me at 4500rpm and the 15" would place me at 4900 which is 100rpm to much. I'm rated at 4400 to 4800 rpm's. I usually ride with the family and friends usually 5 to 7 people and we tow a tube so what do you guys think about going down to a 15" and being approx at 4900rpm?? or maybe it just might put me where I want to be 4800!!

 

[propmann]

Re: Prop under perfoming??

Its the turning point prop they don't work very good on I/O's, Return the turning point and buy either another Volvo penta or Solas they are the exact same prop, just solas is $30.00 cheaper usally.

 

[Dhadley]

Re: Prop under perfoming??

When we want to test without the tabs we will unhook the cylinder and just secure them up out of the way. Are they flush with the hull when parallel?

 

[AngelC]

Re: Prop under perfoming??

Dhadley....

They are flushed with the hull when I disconnect the cylinder and lift them up. When I installed them they were fully deployed; meaning just hanging and when I lifted them up they would be flush and parallel to the hull. They were mounted exactly according to the instructions. Here is how they are mounted and set right now. I have them set right in in the middle setting which is number 3

I did call Turningpoint and told them about my situation and they had said for me to return the 19"prop in exchange for the 17" he said that would work alot better for me and put me at about 4500rpm which they say is 220hp. He had also said that the 15" would not get the boat out of the water. So I think I will order the 17" and take it from there.