help with upgrading prop

hail mary · **Joined:** Tue Dec 17, 2013 11:50 pm **Posts:** 33

anyone change their stock 3 blade prop to a stainless 4 blade, the fast facts say that the stock 225 sundowner 5.8L prop is a 14.5x19
I want to order a prop with good all around performance , im not sure what size to order ,,,,rotation clockwise>?

ric · **Posted:** Sat Feb 01, 2014 12:50 am

Vensura

hail mary · **Joined:** Tue Dec 17, 2013 11:50 pm **Posts:** 33

yes vensura is a nice prop ,,, so order the exact same stock size or change ?

Walt · **Posted:** Sun Feb 02, 2014 12:02 pm

If you are happy with your current overall performance than the same pitch and diameter should be very similar. You should have a bit more hole-shot (more bite from more blades), top end may be down slightly (more drag from more blades). Typically when going from 3 blades to 4 I suggest going up 1" in pitch. For me, this has resulted in better hole shot, better control at low speeds, and about the same top end/RPM.

Surface Interval · **Posted:** Sun Feb 02, 2014 2:46 pm

Generally, 1 inch more prop pitch will decrease engine speed by 150 to 200 rpm. More pitch equals more load and less rpm. Prop diameter, number of blades, size of blades, cupped blades, double cupped blades, blade rake angle, and other characteristics can all affect engine rpm and boat performance. In an ideal situation we would all have a friend or a friendly dealer with a large selection of props for us to try. With a little research you might come across a place that will let you try props under certain conditions. You'll find that many props are offered in 2 inch increments. This means a probable 300 to 400 rpm difference between sizes. You will probably find more difference in pitch changes, but you often will still find some noticeable differences between brands and models of props. When going to 4 or 5 blade props, many times the diameter of the prop is reduced slightly to offset the increased blade area and resulting thrust load. Unless you are looking for hole shot or some other deviation from stock performance, I would use the stock prop numbers as a starting point. Were you able to check your tachometer for accuracy? From your previous posts this may be an issue. Unless the tach is accurate, you are just guessing.

hail mary · **Joined:** Tue Dec 17, 2013 11:50 pm **Posts:** 33

thanks for the info , i will order new prop with stock numbers , should drop the rpms down, although i feel that that tach is reading high I dont have a way to verify it just yet

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help with upgrading prop

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