prop question for you guys

[schalmat]

Hi all,
I have a 73 steury v-518 18.5 foot with a 165 l-6.the prop that was on it was pretty beat up so i replaced it. the one i took off is a 15 pitch part n#48-78116a40 15p black max. from what i read its not the correct prop for the boat.I installed a 14.5 in 19p prop. how will effect rpms and speed and economy.not sure what the upper limit is rpm wise on these motors.thanks for any help you can give me.

Matt

 

[schalmat]

Re: prop question for you guys

bump
my max rpm with this new prop was 3950,should i be up around 42-4300 .?

 

[steelespike]

Re: prop question for you guys

Max rating is 3900-4300.Your within the range at 3950 but that doesn't leave much room for adding passengers. water sports etc.Your hole shot will likely be slow especially with added weight. Motor will be struggling to maintain speed and to stay non plane at reduced throttle.
You need to be nearer the 4300 with a light load.You may be able to have the 19 repitched
an inch less could add "about"200 rpm 2" less could add up tro 400 rpm.The closer to 4300 the better the performance will be.

 

[schalmat]

Re: prop question for you guys

sorry i forgot to mention i had about 1100lb of folks in the boat also.Thanks for the help!