Prop Boffins

[Mollers]

OK all you prop boffins, I need a little help. I'm currently running a Quicksilver Vengeance 19"P on my 150 Opti. The pull-out is superb and the top speed is just over 40knts at 5400rpm. I know that Opti's rev out to 5750, but mine wont. This is prob due to throttle adjustment not propping. I want to buy a stainless 21"P to use for extended cruising to give a higher cruise speed. I've been offered a Laser 2 which is 21"P, It's the rest of the part numbers that I'm not sure about. They are:- 48 16546 A40 21P. Does anyone have access to a Merc/mariner comp. or parts book to let me know whether this is the prop for me? Thanks.

[Kernow Buoy]

[QUOTE=Mollulnan] They are:- 48 16546 A40 21P.

Yep, that's a Mercury part

[Mollers]

[QUOTE=Kernow]

Originally Posted by Mollulnan

They are:- 48 16546 A40 21P.

Yep, that's a Mercury part

So can I slam this baby straight on there and go flying up and down the Roads at Warp Factor 3?!!

[Pete7]

Originally Posted by Mollulnan

So can I slam this baby straight on there and go flying up and down the Roads at Warp Factor 3?!!

No. If your only pulling 5400 with the 19" then you will have alot less revs with 21" It will be slow use more petrol and put unessary strain on the motor. Sort the revs out first so that it can pull full revs or even higher if you want to turn a bigger prop. 1" equals about 200 revs btw.

For comparison, Stu's ex Scorpion and my ex Tohatsu (both 6.5m) and both light boats with Opti 150s, ran best with a 19" laser II props. Think Duncan has 19" on his 6.5m Scorpion.

Pete

[Searider]

5400rpm 150hp opti 6.5m scorpion for about 41/42 knots.

[Mollers]

Originally Posted by Pete7

No. If your only pulling 5400 with the 19" then you will have alot less revs with 21" It will be slow use more petrol and put unessary strain on the motor. Sort the revs out first so that it can pull full revs or even higher if you want to turn a bigger prop. 1" equals about 200 revs btw.

For comparison, Stu's ex Scorpion and my ex Tohatsu (both 6.5m) and both light boats with Opti 150s, ran best with a 19" laser II props. Think Duncan has 19" on his 6.5m Scorpion.

Pete

It depends what you mean by "Best"? I'm keeping the 19" and will run both. I don't need it to scream out at 5750 as I don't intend to run the thing flat out! What I'm looking for is another 2 or 3 knts at 3800-4000 rpm which is my prefered cruising rpm. I'll run the 19" for general use, wakeboarding etc.

[nugent]

why do i think i have droped a clanger here,,,
bought a 21" wid my new 150 opti on my 6.5 osprey can see that getting changed pretty soon allthough get it in the water first .

[Mollers]

Not sure that you have Nuge. I'm running A 19" on the same rig and I'm not 100% with it. So we'll compare notes eh?

[nugent]

all going well she will be in the water saturday

[Mollers]

Put mine to bed today Gave her a nice soapy wash and dry. Flushed with anti-freeze, nice spray up with GT85. In the Father in laws barn covered up with 1000 bales one side, two tractors and a skid steer the other. Nick that ya' b'tards!!!