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I have a mechanic working on my landcruiser, he has just got a 2nd hand 30hp Yamaha, he seems to think the prop is not the right size,it gets up out of the hole very fast yet the top speed is not what he expected,would any one happen to know what the best prop size would be?
gr hilly cheers.
Mate
Have not got a clue, but is good to see you back.
Shawn
Hilly its not about speed with outboards its about being in the full throttle rpm range u ideally want to be propped to as close to the max rpm without going over
Hard to say without a tacho or knowing what revs it's pulling with the existing pitch prop. The only other way is if someone has a similar rig and has done the exercise but even then loading conditions can change the outcome. What is it on - someone here may have a similar boat. Other option would be someone like Solas who usually have good records as to what has worked on what.
from memory will probably be something like a 9 7/8d x 11 1/4"p for a 25/30hp
Scottar i read Solas has changed names now i can't remember who they changed to, i have never used them but loved the idea how u could buy a prop get it delivered than u get to test it and if wrong size u send it back for a swap
Yeah, I'm not sure Gazza. Someone else has the Solas franchise now - not sure whether their service is the same. The guys up the sunny coast are now Propeller Warehouse.
www.propellerwarehouse.com.au/
Steve told me 6 months ago he was selling, as far as I'm aware the staff there are continuing with their previous services although I haven't been there for a while.Quote:
Originally Posted by scottar
You need a tacho as someone else said
the boat speed will be what ever it ends up being once you prop for optimum revs
prop for too much top speed and will over load the engine
prop for too much acceleration and will over rev it at speed ( or bounce off the limiter)
what is the current prop's size?Quote:
Originally Posted by ericcs
the question should be what revs is It achieving at WOT
prop size is irrelevant unless this is known.
your right matching it to WOT, but when you buy an outboard that size, it usually comes with a standard size prop. 25/30hp yamaha's come with a 9 7/8 x 11 1/4p. maybe he has something much different!