WOT RPM's and cruising RPM's

tony_cliffy

Petty Officer 2nd Class
Joined
Mar 19, 2003
Messages
182
Re: WOT RPM's and cruising RPM's

I finally raised my engine as per the great advice received here. I raised it two holes though (instead of one hole at a time) because most everybody thought the overall adjustment I needed required two holes. I did encounter some ventilation when cornering, but this was strong cornering and not standard steering I typically expect to make. I realize one hole down will help that and will keep that in mind.<br /><br />The goal was adjust the engine height before making a final decision on the prop. I was unable to make a good top end run because I dented the factory aluminum prop while on the water and before the water was calm enough to do a WOT run. So now I want to buy a SS prop but haven't confirmed whether the current 14x23 or a 14x21 gives better peformance. The RPM/MPH figures I quoted earlier should still be the same except for incremental gains I hoped to have achieved through my engine adjustment.<br /><br />I realize I need to "lock in" the right prop size before ordering a SS one. I want SS because I fish a tidal river with lots of stuff and I wan tthe extra confidence of the stronger prop. But now I need to replace the aluminum one but still feel I need to confirm the right prop. What should I do? Also, a buddy says a 14x23 prop is "too much prop" and will spin out when my boat gets loaded down. He says I should get like a 13x21 to rpevent it. I said getting your RPM's right at WOT is what drives prop selection. Should I consider a smaller prop??!?<br /><br />Thanks!
 

Dhadley

Supreme Mariner
Joined
Feb 4, 2001
Messages
16,978
Re: WOT RPM's and cruising RPM's

The best way to buy a SS prop, if you are unsure of the size, is to hook up with a performance center. They will try several and recommend one that suits your specific needs. They will advise but be sure to have the average load in the boat when testing.<br /><br />Dont worry too much about the correct height. A good performance center will likely end up changing that too unless you have a hydraulic jackplate. You will need a different X dimension for a SS than an aluminum anyway. And if you go to a 4 blade that will be different than a 3 blade.<br /><br />When in doubt about which size, after the final testing has produced the optimum height and rpm, we always recommend going to the smaller of the 2. Its way more efficient to add bite (technology) than to take it away.<br /><br />Good luck!
 
Top