prop suggestions for 165hp I/O 18" ?

[dave buckner]

15" 21 pitch good for skiing, and 23 pitch pulls great(however shot due to low lake)(both are aluminum). since i can switch , would going to 25 pitch be reasonable ( for additional speed) when not skiing? generally im cruising 2,200-2,600rpm, but its fun to open up occasionally. im a newbie and not farmiliar with hottest props. i need function , not hype (stainless sounds like the best option). any advice on what will give performance based value greatly appreciated. thanks, dave

 

[Bob_VT]

Re: prop suggestions for 165hp I/O 18" ?

The prop on your boat should be based on WOT (wide open throttle), boat weight and RPM's. Going to a 25 pitch is not the answer to top speed unless your 165 will pull the rpms...I doubt it.<br /><br />If you "overprop" to a 25" the load on your motor will be too high (like starting a car in 3rd or 4th gear) and harm could be done.<br /><br />You should run the boat by the tach. Cruising at 2200-2600 is fine as long as you are planed and comfortable. Your WOT should be at 4200 rpms. <br /><br />If your lake is low the stainless prop will be so strong that lower unit damage could occur if you hit something.<br /><br />I would guess that a 15 x 19 might be optimum for you.<br /><br />Bob

 

[93evinrude]

Re: prop suggestions for 165hp I/O 18" ?

What is your rpm at WOT with each of the two props and what type of boat do you have?By the way it looks at this point,I agree with the last post in that a 19 pitch may be best.

 

[dave buckner]

Re: prop suggestions for 165hp I/O 18" ?

okay , im only getting around 3600rpms (according to tach) with either prop. 23 pitch is noticeably faster. 21 pitch feels like im in low gear. boat is "74 galaxy 17' bow rider with inline chevy 6. original manual shows: 15" 21p 41-46mph 17'boat<br /> 15" 23p 44-51mph 17'boat<br /> 14.5" 25p 48-55mph "dual,fast"<br /><br />this originated question about 25 pitch. i do not understand what "dual, fast" means listed under "approx. boat length" in factory manual. <br /><br />as far as low rpm's, i suspect tach is not accurate. motor sounds like its hummin at WOT , it just feels like im dragging anchor with 21 pitch prop. by the way 15.5" 19pitch shows 37-42mph on 19-21'boat in manual. any help deciphering this manual info appreciated. thanks, dave

 

[DJ]

Re: prop suggestions for 165hp I/O 18" ?

Hi Dave,<br /><br />You've got to get your tach. right before you can make a decision.<br /><br />I'm assuming the engine is an "in-line" six cylinder? GM based?<br /><br />If so, that engine is happiest with a MAX. WOT of 4300.

 

[93evinrude]

Re: prop suggestions for 165hp I/O 18" ?

As djohns19 suggested,you should verify that you tach is accurate to begin with since you suspect it isn't.Also, you didn't mention what your tach and mph readings were with your existing props.Is your speedometer not working as well?If it isn't you will need to repair it as well or you could use a gps,I guess.