Prop Change Questions.

[Harritwo]

I have a 94 Sea Ray 170 Signature Series with a 3.0L Mercruiser, Alpha 1 Gen II outdrive, currently propped with a 14-1/2" dia 19 Pitch Alum 3 blade prop. WOT is 4400 RPM's and 34 MPH by GPS. I wish to change props to a Solas 4 Blade in the hopes of increased performance and maybe speed. When going to a 4 blade, will pitch and diameter remain the same for WOT or which way should i go on pitch and diameter. IBoats is having a sale on the Solas and this would be a good time to buy for me. Any help, thoughts, recommendations are greatly appreciated.

George

 

[Chris1956]

Re: Prop Change Questions.

What is the max recommended RPM for that motor? I will bet you are at or close to it right now. If your current prop is damaged, a new one will give better performance, however, if it is not damaged, the change will have little effect.

Are you trimming the OD to gain max speed?

 

[Harritwo]

Re: Prop Change Questions.

WOT is 42-4600 RPM. No damage to prop, just wanting to increase performance/speed if possible and wanted a new/spare prop. I trim to obtain speed and ride as high on the water as i can without porposing.

 

[Chris1956]

Re: Prop Change Questions.

Sounds like you have the correct prop already. I would stick with the same pitch.

 

[Starcraft5834]

Re: Prop Change Questions.

"94 Sea Ray 170 Signature Series with a 3.0L Mercruiser, Alpha 1......"

Im not familiar with size of your boat, I can tell you I've got a 3.0L Alpha 1 on my 1987 20ft cuddy. I replaced my 3 blade prop with a 4 blade Solas 15p,, it's 14.75 dia (i think). I had to remove the fin anode and install a flat anode.. My observations on change are the following...

hole shot went from feeling like I was trying to pull a large appliance out of the water on plane, to with a 4 blade, up on plane in less than 5 seconds.. that's with 5 adults in boat too... Steering improved at slow speed a great deal with the 4 blade. Top end speed went down about 2 mph,, WOT 33mph 4500-4600 rmp with the 4 blade solas...... Make no mistake, I dont think anyone has ever increased top end speed by going to a 4 blade.. If you tube, water ski,, you want the 4 blade... period.. 4 blade is generally better in more areas than the 3 blade.. others may disagree.. those are my findings...

 

[steelespike]

My limited research indicates a lightly loaded 170 like 3.0 with a 21" pitch 3 bld. would struggle with a load or hole shot
but would run about 40ish. 19" often over revs if lightly loaded.
Check some simple things; does throttle open all the way? is the timing set right and advancing as it should
Bottom clean and smooth?Motor in excellent tune?

 

[GA_Boater]

An old thread which was re-opened.

Closed.