Prop and adjustment question

[krovar]

1977 ranger 17 foot with a johnson 115 first how far below the bottom of the boat should the prop shaft be next had a 13x19 ran ok pretty bad torque to right could not trim up very much without slip, whent to 14x17 with alot of cup extreme torque to right loss rpm and speed, tried 13.25x19 hp with solid hub bad torque to right and lots of vibration when trolling good speed low rpm do i need to raise motor. ps someone has put a spacer plate under motor which leans the motor out 1 inch at top PLEASE HELP

 

[Bifflefan]

Re: Prop and adjustment question

First, the ventilation plate should be even with the bottom of the keel. Sounds like you need to lower the motor.
Second, all that prop changing is never going to cure the torgue steer. You need to adjust the tab behind the prop to compensate for that. If it wants to steer to the Left, move the rear of the tab to the Left, and to the Right if it wants to steer to the Right. Make small adjustments at a time. But start with about 1/4" off center and go from there.
Third, I would take out that spacer, the motor whould be level with the transom.
Forth, loose the solid hub prop. Your just begging to break something.

 

[steelespike]

Re: Prop and adjustment question

We really need details.Lets try the 19 with a light load we need the max rpm and speed at wot.
Tell us how high the motor is on the transom. Woulds it trim just a tickle or about half way etc.
Does the boat resapond to up trim?
Were these prop new or used? Were they in excellent condition?

 

[krovar]

Re: Prop and adjustment question

max rpm 4800 if you trim up a little you gain to 5300 rpm and lose speed the boat acts like it runs to flat likes to nose plow,the prop shop told me to raise the motor till i have the prop shaft 4 to 5 inches bellow bottom of boat i raised it 1 bolt hole and im still 6.5 bellow bottom, i have changed tab ever way and it still torques to the right bad, they told me to raise the motor that what was causing my torque problem