Prop 18 classic ss drive 300+ hp

[jstokes8407]

I looking to get more out of my boat. Its a 18 classic has a SS Drive 300 + HP Has a 23p ss quick silver on it now it tachs about 5 k and in the low 60's . Thinking of a 3 bladed 23p chopper prop or a Hydromotive IV 4 blade 23p prop anybody have any ideas where 2 begin or had any good recomendations ?

[Rootsy]

you are saying you have an 18 with an ALPHA SS sterndrive and 300+ hp???? you should be a lot closer to 70 than you are to 60... with that said... hydromotive quad IV O/T

[BUIZILLA]

why would you want a lefty 4 blade for a righty SS drive??

[jstokes8407]

that was just a picture of a Hydro 4 blade. Rootsy Can you tell me more on hydromotive quad IV O/T. I guess my boat does around 65. I have about 12 hours on the new engine.

[MOP]

John it wet and borrow some of my wheels, 9 and counting! The 23 cleaver may do some good, maybe I'll let you try the 4 blade that got mine going so good. I just picked up another 4 blade to try when I get wet. Call me when you are ready.

Phil

[mphatc]

I ran a Q IV last summer on my 18 with 333 HP and Bravo which was good for the low 70's . . . I believe it was a 23 LH solid hub , Poodle lent it to me.

For which I owe the man some beers!

MOP, I sent you an email, please post me offline!

Mario

[mrfixxall]

I dont think you wanna leave a 4 blade on a ss drive.the hydromotive has too much "BITE" and you may brake the drive if you pop the boat out of the water...

Just a thought..

[Sam]

On my 16' / Alpha SS combo I run a 24.5" Hydromotive OT which has the smaller dia vs. the QT. In my case I couldn't get a 3 blade to run without the boat acting like it was on crack :eek!: and I tried a lot of them. Once I put the Hydro on it calmed down considerably. I'm not into hole shots but my take offs improved with little to no cavitation. The only thing you need to watch out for is the Hydros tend to give you more stern lift. This can be both good and bad you just have to see how your boat runs.

I agree with Jamie, you should be in the 70mph range with the correct set up. Not knowing how much experience you have with the SS let me be so bold and give you some pointers. Keep your eye on the temp gauge, with the low water pickups the SS has a tendency to suck weeds. If this happens you need to take the side plates off and hook or flush them out :bonk: . Change the drive lube every 25 hrs, it gets hot even with a drive shower. If you break the upper half of the drive you are SOL they are nearly impossible to find. Good Luck!

Sam

[Rootsy]

the quad IV (the big one) is more for high X ventilated hull applications that don't need lift.. it does not have the rake nor the cup to provide and hold adequate bow lift (or stern suck)... it runs flat.. keeping more hull in the water therefore adding stability at the cost of speed...

the O/T is an outboard prop.. has a small hub, smaller diameter, more rake and some cup on the tip... Hydromotive or whoever you get it from (throttle up has the best prices and service) will put a block off ring on it so that if you are running thru-prop exhaust it doesn't go over the hub and cause blow out...

the O/T on our light hulls, much like a bassboat, etc, adds lift over the Quad IV... the smaller diameter (the blades are the same size, just moved closer to the propshaft C/L) allows for more rpm due to less mass swinging out there... it is still stable but less so than the Quad IV because now you can pick the hull up and less of the hull is in the water...

I've run a 23, 25, 26, 27 and 28 Quad IV O/T on my 16... the 27 was my choice with my 1.59 ratio Alpha SS... once i went to 1.47 i had to drop back to a 25... and i was running anywhere from 75 -77 mph with the 1.47 ratio and with the 1.59 and the 27P i saw 81.3 GPS....

the prop bites well, gets on plane well, is stable, holds well in turns, lifts the boat up nicely... at WOT it has a tendancy to need to catch up to itself if you really ring it with a lot of torque... but on my 16 it ran 9% slip from 3000 rpm to WOT...

was the BEST all around prop i tried and i ran 3 blades, 4 blades, cleavers, round ears, semi cleavers, hydromotives, turbos, mirages, quicksilvers... about a dozen props in all... there were some others i had wanted to try in the hydromotive line that would probably work very well on the 18 with the high propshaft.. namely some of hydromotives 3 blade Outboard props...

Be aware also that hydromotives can come rubber or solid hub.. you want rubber... and they should NOW be coming with the square hub system so they work with the flo-torque hub i believe...

[AC18Classic]

My 18 has the 350 MAG 300hp with Bravo 1 drive & a 25 3 blade - I am getting in the upper 60's.

[jstokes8407]

Sam
I have had the boat since 99. The 1st time I took it out the drive blew (ouch) $ 2800 later . I know all about the low water pickups . Got some sea weed in it once and took awhile 2 figure it out. Glad I got the fresh water cooling system on it. I have a 27p prop that came with the boat. It cavites like hell out of the hole but is like a go cart it will keep picking up speed as i'm going and only tachs at 3400. It have a 23p on there now and it says 65 - 66 on the speedo but I would need gps to get an acurate MPH.

Mop I'm gona take you up on that offer as soon as we get some nice weather

thanks for the help guys