peaky motor, light hull, prop thoughts?

[pcrussell50]

with my current setup as it is, i feel like i'm a good deal under-propped as i have to throttle back a good bit in cruise to keep from over-revving the motor, and not just by a little. it will go way past 6000 rpm, where the motor's peak power is rated at 5500.

hull: the boat is 16 feet from transom to tip of bow, and it looks like a sidewinder low profile, or a tahiti. it's also bereft of almost anything that adds weight. it only has a single bench seat that faces fore and aft with the one backrest in the middle. that's it for seats. it has the remote control and a tach and a cheap, $15 bilge pump, a little thin carpet, not even full coverage, and that's it. no lights even.

engine: the engine is a v4 crossflow evinrude 135hp. most ordinary boats i see with 135hp are a good bit bigger and heavier.

the current prop: on it now is a stainless 3-blade of an unknown brand, [it came with the boat, along with a couple of other cheap aluminum props for pulling skiers]. it appears to have been worked a little, according to the wife's dad, [former bass boat test driver], and it has 21 written on it with a sharpie. i have not had it to a prop shop to verify. but for the sake of argument, let's assume it really is a 21".

the NEW prop: i just bought a 24" Raker in perfect shape, for an unbelievable steal. it may be too much, but for the price i paid? what the heck, right?

thoughts on peakiness: this motor, being the v4 crossflow evinrude was used for 85hp all the way up to 140, i think. and if that's true, i'm thinking it must be very peaky, with most of the power coming in late and hard, in comparison to a broader torque curve in the lower powered versions of the motor. it weighs 315lbs, which i think is light for 135hp, [and probably heavy for 85hp]. so, even if the 24" raker is good for the top end, and allows me to finally run this thing at WOT, i worry that the soft bottom, peaky nature of the motor will have an awful holeshot with 24". i also think that 24" is the most you can get for the "small gearbox" v4, so c'est la vie.

oh well, it was cheap and i'll be anxious to try it.

-peter

[rdkvector]

I think that prop will surprise you. A Raker is ventilated to allow you to spin up a larger prop. Rakers are GREAT all around ferformers, if you can't spin it up to 5200 to 5400 rpm, then raise your motor up another inch and watch your water pressure. Please post your results, we can guide you when you give a baseline to work with.

[delawarerick]

Watch you dont lug the motor that is a tall prop for an xflow v4. I ran a 22 raker on a modded 110 xflow on a 16 stripped rallysport and it was at the limit yet raising it and running an srx 23 was perfect. Close off the top water hole if your gonna raise it. It will give you another inch. Raker is a great prop it does it all. The raker went to flambum and he runs it on a 16 baja/140 v4 xflow. Rick

[Bajaha]

Peter , my 1984 16' Baja has a140 x-flow with only port clean up work, fiber reeds and better heads. I also have a 6'' setback jack plate and am running the P/S about 2.5'' below the pad. I did fill in the top water pick up hole, as suggested by Deleware Rick to maintain good water pressure,

I have run both SRX and Raker props , and the raker is my favourite.
Currently i have Two rakers ,a 22'' 59 mph gps and a 24'' 61 mph @5900

The boat leaves hard with just enough spin to help it get on plane and then hooks up and goes.

motor height is very important in making the larger pitch props work.

Also you should install a torque tab on the skeg , if you start raising the motor.
Have fun with it.
Glen

[David]

I don't think you'll find the motor peaky. The higher HP versions were not hot rodded 85s, rather the 85s were detuned.

I've got a 100 HP (propshaft) Johnson on a 16' Baja. A bit less power than your 135 crankcase. My boat has full seating etc, so it might be a bit heavier. With 1-2 people on board, a DAH 23 SRX works very well. So 24 doesn't seem like too much for you

Of course my boat is put away for the winter, and you can still try things.

[pcrussell50]

thanks, guys. great info as always.

delawarerick, thanks for the tip about lugging. i'll watch out for it. if i can't swing the 24" raker, oh well. i paid so little for it i'm not too worried.

to all who suggested blocking the top water pickup hole... great idea. wish i'd thought of it myself. is there a reversible way to block the top two water holes so i can give it a try, but put it back in case i don't want to keep it that way?

also, i forgot to mention, i have a 6" setback from a CMC tilt system. i hear setting the motor back can buy you a little slack to raise it, though i don't really know how much lift a measly 6" setback is good for.

thanks again,

peter