Prop Change Question

[bhammer]

All,

Details
2007 Merc 4.3L FI 220HP Alpha
2007 Starcraft 1900 Limited about 3500#
Smart Tabs

I currently have a Solas Rubex 3 blade - Aluminum 14.8 Dia. 17 Pitch and with the normal load of my boat, I run about 4300/4400. I only see 4400 on a glass lake with empty fuel. I GPS about average 35 with runs into and out of wind.

I would like to get my RPM up more closer towards the 4800 end. I don't run full out much but would be nice to run in the higher end and not lung the engine. Most of the time, I am pulling skiers and tubes. Decrease on plane time would be great but not so much that I would want to sacrifice the top end speed I have now. With the tabs, if I don't have a skier, I plane right out but a fat guy like me takes a bit too much to get up and going.

Without your crystal ball, what could I expect from each:

1. Go to a 3 blade Aluminum 15 Dia. 15 Pitch
2. Go to a 4 blade Aluminum 14.75 Dia 15 Pitch
3. Go to a 3 blade Stainless 14.75 15 Pitch

My WAG is that if I go to a 4 blade that I would pick up speed as well as decrease the time to plane? Or, would I see an improvement in plane speed with the 3 blade based on decreasing the pitch?

Your thoughts?

 

[trendsetter240]

Re: Prop Change Question

1. Go to a 3 blade Aluminum 15 Dia. 15 Pitch
2. Go to a 4 blade Aluminum 14.75 Dia 15 Pitch
3. Go to a 3 blade Stainless 14.75 15 Pitch

My WAG is that if I go to a 4 blade that I would pick up speed as well as decrease the time to plane? Or, would I see an improvement in plane speed with the 3 blade based on decreasing the pitch?

Your thoughts?

I think you will definitely see an improvement with all three choices. The most accurate estimate of what you will see when you change props is if you stick with the same manufacturer and style of prop.

My crystal balls tells me that....

Option #1: A solas rubex or amita 15p 3 blade Alum. will put your WOT RPM about 4800-4900 and give you improved hole shot, better pull for lifting heavy skiers and aout the same top end, give or take 1mph.

Option #2: A solas Amita 4 blade 15p Alum. WIll put your WOT RPM right about 4800, give you a great hole shot, easier to plane at lower speeds and maybe drop 1 or 2 mph for top end.

The reason I wouldn't say go get a new SS prop is that you are changing designs and materials and your RPM might end up too high or too low.

I have a bunch of props and among those is a solas amita 13p 4 blade alum. It's a great power prop and I use it whenever I have heavy loads or want to pull a skier.

 

[bhammer]

Re: Prop Change Question

Thanks for the input. I have also thought about going to the Turnig Point because of the cup. I have one that I use as a spare because it's been repaired. I got about the same numbers with it.

 

[Don at Kawagama]

Re: Prop Change Question

Hello All,

I have a 2006 150 Merc OB 4 stroke and have to replace the prop. I have the prop and spline stuff from the dealer, but the boat and motor are a long way away and I want to know what wrench size and othet tools I made need to do the change out. I am in a remote area to do the change so I have to go prepared. By the way the prop is a standard merc prop and I have the lock nut kit.

Thanks in advance.

Don at Kawagama