17 Alii kai motor shaft

Randall808

Newbie
Aug 20, 2020
3
0
42
oahu
Name
Randall Kobayashi
Boat
Aliikai
Aloha all,
Anyone that own or have owned a 17 Alii Kai and ran a 90hp, what shaft length did you use. I know some with 20 and some with 25. Any advice would be appreciated before I purchase. Mahalos
 

Addicted2fishin

where's da fish
Jun 16, 2006
850
12
45
Hawaii
Name
RJ
Boat
19 Glasspro, 17 Ali'i Kai
Aloha all,
Anyone that own or have owned a 17 Alii Kai and ran a 90hp, what shaft length did you use. I know some with 20 and some with 25. Any advice would be appreciated before I purchase. Mahalos
On a stock transom a 20" is perfect. A 25" will cause more drag and with the same hp and same engine you will not get top end max knots. Trust me. Lots of trials and errors. My dad is running twin 20" on an extension built too high for it. It cavitates and he cannot plane properly. With 25" he would have been fine but hard head my dad LOL.
 

Randall808

Newbie
Aug 20, 2020
3
0
42
oahu
Name
Randall Kobayashi
Boat
Aliikai
On a stock transom a 20" is perfect. A 25" will cause more drag and with the same hp and same engine you will not get top end max knots. Trust me. Lots of trials and errors. My dad is running twin 20" on an extension built too high for it. It cavitates and he cannot plane properly. With 25" he would have been fine but hard head my dad LOL.
Mahalo. I'm sure we'll have our share of trial and error before this is done..lol
 

Addicted2fishin

where's da fish
Jun 16, 2006
850
12
45
Hawaii
Name
RJ
Boat
19 Glasspro, 17 Ali'i Kai
Mahalo. I'm sure we'll have our share of trial and error before this is done..lol

if stock transom run a 20. If Improperly mounted Force transom mount 25 LOL. I used to fish with a friend of mine who had a Yamaha 90 20" and we flew to Miloli'i at 29 knots to help tow back a bigger boat. A few months later we installed a 90HP ETEC with 25" shaft which we thought would be overkill for the boat. Boat would not hit 25 knots. No matter what. Too much drag. He sold that motor in less than a few months. Bought another 90 short shaft but sold the boat shortly thereafter. For the Unicorn.... an 18' Alii kai. Not extended. But built by the Berdons stretched. That boat was wonderful until he sold it for a Force 18 and then my dream boat. A Bolos 20.