Outboard problem

[Enmiga]

Hi everyone, I have a 26M I'm Italian and I live in Italy, I have a problem with my outboard, it's a suzuki 50hp from 2005, it has a short stem. the problem is that when I go to the motor and I am at 5000 rpm the propeller starts to thrust I have to lower the turns and I can't go beyond 7-8 knots. how can I improve this situation? can I extend the motor shaft or change the propeller? the house says 60hp but up to power it can be mounted? thanks for the answers and sorry but I used the translator.

[Tomfoolery]

Is your antiventilation plate even with the bottom of the vee of the hull? If it's higher, that's the problem. It must be even or the propeller will suck air (called "ventilation" - NOT the same as "cavitation").

Slide down to picture.

https://www.mywestshore.com/boat-transom/

Il tuo piatto anti-ventilazione è anche con il fondo dello scafo V? Se è più alto, questo è il problema. Deve essere pari o l'elica attirerà l'aria (chiamata "ventilazione" - NON come "cavitazione", che è simile ma diversa).

Scorri fino all'immagine.

https://www.mywestshore.com/boat-transom/

[Carioca]

Need 20 " outboard leg with a 12 x 3 x 9 pitch prop.

Maki katsu fari ??