Prop pitch for a V4 Evinrude 90 ?

[MikeZed]

Hi there,

I recently had the prop stolen from my boat outside my house, and am now trying to replace it.

The boat is a ski-boat, with a 90 V4 2 -stroke Evinrude on it, a flat hull and used to go fantastically.

What i've worked out is the following :-

Diameter seems to be 13 1/4 - i tried a 3 blade aluminium 13 1/4 with 17 pitch on it, and it went well on the top end, but couldn't pull a skier out of the water. From my research on this forum, it'd seem that i'm lacking "hole start".

There's a 13 1/4 4 blade 21 pitch available, will this fix my problem ? Should i be looking for greater or less pitch to get more power ? I've got top end speed to spare given i mostly pull skiers with the boat, so happy to lose a little top end to get a bit more power to pull skiers out.

Thanks for your help in advance, i've Googled for hours without working out the answer

 

[smokeonthewater]

Re: Prop pitch for a V4 Evinrude 90 ?

for holeshot less pitch is your friend.... more pitch = more speed

 

[MikeZed]

Re: Prop pitch for a V4 Evinrude 90 ?

Sorry, forgot to answer the basic questions :-

1) Performance issue you are trying to correct.
2) Current prop manufacturer, model, aluminum or stainless and as a minimum.
3) Current prop diameter and pitch (required).
4) Wide open throttle RPM and speed with an average load (very helpful)
5) Engine/drive make, model, year, and HP
6) Boat make model, year, length and weight

1) Need more power to pull a skier out of the water
2) Not known due to prop being nicked
3) Tried with a 13 1/4 and 19, and not enough power
4) No RPM gauge or Speedometer - so not known
5) Evinrude V4 90 - not sure of the year
6) flat hulled ski boat, 4.8m long, not sure of weight

 

[steelespike]

Re: Prop pitch for a V4 Evinrude 90 ?

Do you trim in for hole shot?Do you move passengers forward till planed off?
You need to be sure your prop selection is right.The only way to be sure is with a tach and speedo.A gps is best. A tiny tach is reasonable and easy to install and one for your motor will fit any 4 cyl 2 stroke. Not knowing your present max rpm its difficult to make a prop, selection.It would appear a 17" pitch would be closer to what you need.And will improve your hole shot but the question is will it over rev.
If you force your motor to run over or under its recommended rpm range it could lead to premature engine problems,poor performance and economy.

 

[hwsiii]

Re: Prop pitch for a V4 Evinrude 90 ?

Mike, without a tachometer and GPS you are walking around in the dark and it is just guesses that you without basic information.


H