Best Prop for 1983 V6 Mercury 150hp for Top Speed?

[Faztbullet]

yea but the checkmate has a pad.....

 

[flyingscott]

I will put this comparison up. My Dads 1984 starcraft ss180 with a 1985 yamaha 90 hp. Now the ss180 weighs about the same has the OP boat. That being said aluminum 17" pitch prop 5500 rpm 40mph with 2 people in it. I know it's not a direct comparison but my dads boat gives up 60 hp and a lot of displacement and has rivets sticking out of it. My other comparison is my friend owns a starcraft tournament 180 runs a high 5 19" pitch with a 175 efi merc at 5500 rpm 48 mph. That boat weighs 1400 # without all his fishing gear and gas and kicker and the high 5 is no speed prop. So I am going to hope the trim is the problem because that prop looks fine. And I am going to ask did you test drive the boat when you bought it.

 

[Frank Acampora]

While your current prop looks in decent condition, it is the stock round eared design and aluminium. Not meant to go-fast. Test a couple of high performance stainless props (if you can ) and buy the best. Of course, with trim all the way in, the bow is down and you are plowing water with a lot of wetted hull area. You definitely need to get the trim up and the hull to ride looser.

I personally like the Ballistic design stainless. It has more blade area and is fully cupped. It has less slip so you get more speed for your RPM. A 21 pitch would probably be close to what you need.

 

[Fantasvas]

Update: Just got back form the lake today. Had the new prop on (Solas Amita 14.3D x 21P 3-blade aluminum). Boat ran great and new prop made a big difference! - just me in the boat. Water was a little choppy. Boat flew right out of the hole and got right into plane - no cavitation whatsoever (motor trimmed all the way down) - what a difference from the old prop! Opened her right up WOT and she hit 46-48MPH at 5000RPMs (no GPS) with motor still trimmed down. Started trimming her up and got to 53-55MPH WOT at 5800RPMs (water was choppy) - At that speed I noticed I had less control of the boat - when I trimmed her back down a little I started getting more control back - I've never had the boat go this fast and it had great acceleration! I wonder what a Stainless Steel prop will do on this boat? If I go stainless I might have to go up in pitch to 22" or 23" - I'm worried that the RPMs were too high at 5800 WOT - my guage only goes to 6000...

 

[flyingscott]

Awesome good for you I am glad I was wrong

 

[fhhuber]

Yes the 5800 is high. Most of these 150 2-strokes shouldn't be pushed past 5500. They'll usually take it for a short time but a broken rod is not a good thing. Throttle management or more prop...

More weight in the boat will slow it down and load the prop more so it would be a good idea to do a fully loaded run.

 

[Fantasvas]

fnhuber - Yeah, for right now with that prop and just me in the boat, I'm not going to push it past 5500 - it runs great at 5000 - 5200 RPMs and hits about 50MPH - that's fine for me till I change out the prop or even if I don't. Not going to push that motor...thanks for your good advice...