prop for 98 sea ray

[micsol]

i have an 18' bow rider with the 3.0l mercruiser and alpha 1 out drive(2.0 ratio). the boat has a 17 pitch prop (not sure of diameter) that was on it when I bought it. right now a WOT empty i get 4800rpm and 35 mph. with 5 people in the boat. I get about 31mph, and 4400rpm. I am mostly doing watersports tubing etc. I would like to get a little more cruising speed. right now i cruise around 25mph. I dont want to completely kill my holeshot though. what options do I have. also Ive never ordered a prop before, do i need to order anything with the prop or will the new prop come with everything I need

 

[Maclin]

Re: prop for 98 sea ray

The numbers you gave point to the current prop being the ideal balance between hole shot and top speed. Any lower of a pitch will give better holeshot but yield a lower top speed. Any higher pitch and the engine would not be able to hit top RPM and the tops speed would be about the same or lower, and holeshot would definitely be worse.

 

[steelespike]

Re: prop for 98 sea ray

Is your speed by gps?
I my opinion your 3.0 with a 17" prop 2.00 ratio should be over revving.
I don't know if the Sea Ray is really heavy or has a really deep V all the way to the transom but I think if healthy motor could run a 21" prop.
Not for water sports but for light cruising wot about 40 - 43

 

[micsol]

Re: prop for 98 sea ray

Speed and rpms are off the speedometer and tach on the boat

 

[steelespike]

Re: prop for 98 sea ray

With a gps speed we can tell if the rpm makes sense. Some cells have a gps app.
A 17" prop would normally be for water sports with a load.With a caution to watch the rpm with a light load.
perhaps it needs a tune up.
Maybe check that the throttle opens all the way.

 

[micsol]

Re: prop for 98 sea ray

With a gps speed we can tell if the rpm makes sense. Some cells have a gps app.
A 17" prop would normally be for water sports with a load.With a caution to watch the rpm with a light load.
perhaps it needs a tune up.
Maybe check that the throttle opens all the way.

Something I forgot to mention in my original post this is at altitude 6600'. And I knOw that has an effect

 

[jestor68]

Re: prop for 98 sea ray

Yes; altitude has a rather large effect(power loss). To the tune of nearly 4 % per thousand feet of elevation.