have to guess starting prop pitch

jaxnjil

Lieutenant
Joined
Aug 3, 2007
Messages
1,368
hi guys;
the prop i have now is a quick silver 84-163114-A5-17P. I was able to talk to the previous owner and he told me has had the alpha drive gears changed to 1.32:1(i think thats what he said) to compensate for the elevation here. he didnt get around to getting reproped before he traded the boat off.
i havent had the boat in the water yet so i wont be able to answer any rpm questions yet.
he told me he got the above prop from a buddy as he was still trying find the proper pitch. it was the summer of 06 the last time he worked on it so he cant rember what his rpm's were but he did say it still need sorted out.
it gets better. the prop has been repiched and he dosnt rember if it is higher or lower. just that is still not quite right.
last year i bought a 15"x17 pitch black max. i am going to run this prop to find out where i stand for rpm to try to find a base line
my problem is when i was looking at the box for my black max i found out it is rated for 250 hp or less. i'll only be able to use it for one run and then have to take it off. there is also a 15"x19 aluminum rebuilt prop on the boat but again the guy isnt sure if it was repitched
i'm going to have to buy a prop and its is going to be a guess for you guys because i know you as i dont have enough info to be sure.
the question is; what is the next prop mercury make that will stand 330 hp and sill preforme like the black max(if they even do) and does a 15"x18 pitch sound like a good place to start.
if possiable i want to stay with aluminum not ss

the reason for all this is i'm going to lake powel for my first trip and i could get props there but no help trying differnt pitches. you run it you buy it. no return or exchange.
 
Last edited:

steelespike

Supreme Mariner
Joined
Apr 26, 2002
Messages
19,069
Re: have to guess starting prop pitch

Maybe you have no choice but if I was spending my hard earned money on a prop I would be buying where I could test props.
In your situation I'd remove the prop and have a prop shop check the size.
then use it for testing get the max rpm and speed,a feel for the hole shot.
your typical load, activity get the figures to us.A bit of a pain but will be worth it for the health of the motor and performance of the boat.
 

jaxnjil

Lieutenant
Joined
Aug 3, 2007
Messages
1,368
Re: have to guess starting prop pitch

well i found a 14"x18 4 blade to day for $35 and i have the15"x17 and found a 15"x19 so hopefuly i'll be able to get in the ball park
i would use the prop return here but i do'nt know how i would get ups down there.
also i messed up when i stated the drive gear ratio. i think it should have been 1.32:1 till i get it on the lake and get some numbers its a crap shoot.
 
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