Alpha 1 prop choice ?

[putback]

Boat is a 1985 19 ft glass V hull starcraft 3.0 140hp alpha 1. My 1st I /O, just finished the rebuild. Tried it gently up to 3500 rpm, seems fine. It has a stainless prop, 48.. 11074-A40 23p. As a donor boat I have the same in 16 ft. It has an aluminum prop 48..78116-A40, 15p. I presume I have a 23 and a 15 pitch? I'm more interested in a very slow troll that speed. I noticed with the 23p prop she idles just slow enough for a slow troll but barely for my needs. Will the 15p prop go a bit slower, any pros and cons?

 

[alldodge]

After your break in period, see if you can reach WOT around 4800 rpm, this is for overall performance.

Troll speed: If 23 pitch allows for 4400 to 4800 rom your good, my guess is it will take less pitch but not quite 15 pitch.

If 23 reaches WOT within range, then if you use a 15 pitch, your hole shot will be neck breaking, but you will also over rev at WOT. You will also probably be running high rpm's just cruising down the water at slower speed. If 15 pitch reaches WOT range and you use the 23, the hole shot will be a dog and you will be lugging your motor on plane