Prop size

new to outboards. have purchas

new to outboards. have purchased 14ft half cabin with old blueband 85hp mercury in good condition. existing prop is 48 65024A 1 19P but is damaged. Spare prop is very good condition but part number 48 32390A 3 15P.
Q what will be effect of putting on the spare and will it be suitable for the motor. intend to use boat for fishing and ski with children.

what is your WOT (wide ope

what is your WOT (wide open throttle) RPM
u will gain around 800 more RPM which maybe not good for the motor

thanks for response but have n

thanks for response but have no idea of engine speed as boat does not have rev counter. From your comment it would be better to get another 19P prop? and trust that it is the best match for the boat.

"I would first buy a rev count

"I would first buy a rev counter (tacho), then fit the 15p prop. The 15p prop is better suited for skiing as you get better acceleration from standstill and place less load on the motor.

Also it is unlikely you would be flat out at maximum rpm towing someone anyway plus for fishing you will get a better trolling speed too.

You can also adjust your throttle so it doesn`t go above your maximum rpm anyway.

You will loose some top speed but won`t be much.
I use a 15p on my 16ft runabout with a 150Hp Blueband and still get 62 kmh(38 mph) at 5500rpm. Plenty fast.

Just don`t go over your maximum rpm and you will have heaps of fun.

Kris"