Hp upgrade

[rlpruitt]

i have a mariner 1989 90hp mo

i have a mariner 1989 90hp mounted on a 24ft tracker pontoon. i am using a 17pitch 3 blade prop. is the hp rating at the foot or at the powerhead and if at the foot can it be increased by exchanging the foot for a 115hp rated. my kids want more speed when tubing. now running at about 15mph pulling 2 kids and 3 passengers. will run 20mph when i am alone not pulling any kids. i have a stainless 21 pitch prop but my boat dealer told me it would eventually hurt my motor to use this prop so i keep it as a emergency back up.

thanks

 

[olmo40]

Hp is rated at the Prop shaft.

Hp is rated at the Prop shaft.Your dealer sounds right about the props .Simply you need a bigger motor .You will be disappointed with any modificatins to your 90hp.

 

[rlpruitt]

thanks

i thought that would

thanks

i thought that would be the case