# Bulls Bay 151, Yammie 70 2 Stroke.



## pjpoppet (Feb 20, 2015)

Ok ive got a thread over in General in regards to fine tuning a prop for this boat and motor combo, long story short, i had a 50 tohatsu on it, found it underpowered, max speed was 33mph on a good water day, swapped over to a Yammie 70 2 stroke, first run was 37 with a 13 1/4x 17 in pitch genuine alloy prop, reasonably pleased, then had it fully serviced, tech found ignition timing was out and wasn't quite getting full throttle, next run was 38.9 and hitting 6000 rpm very easy, not much extra speed from 5700-6000, so I purchased a Alloy generic 13x19 pitch prop and lost speed and rpm down to 34.5 and 5450 rpm, so I thought 17pitch is about spot on, sourced a 12.5x17 stainless prop its marked 17k, not sure if its a genuine Yammie prop, and again I lost speed, down to 36.9, still hitting 6000 rpm very easy, hole shot is spot on, engine is mounted 1 hole from top with the plate just above water level when planing, the boat weighs approx 1350lbs with me in it full load, live well empty, Im sure I should be able to crack the 40mph mark with this combo, theres not many small skiffs here in Aus to compare too, now Im thinking 18in pitch may be the right way to go, or even a jack plate (unsure), all speeds taken on GPS, perhaps the diameter of the Stainless prop too small? Id love some responses from those who may be able to offer sound advise, one other thing all props never really get the nose too far out of the water. With regards Justin from Australia.


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