Author Topic: Best Prop for Speed  (Read 19052 times)

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Offline 17ireid

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Best Prop for Speed
« on: May 26, 2015, 01:08:17 PM »
Hi,

I have a CVX 16 yet to hit the water, probably be ready this summer. I am working on purchasing a 1978 Mercury 115hp for it and I'm looking for a prop to put on it. I am mostly interested in top end speed and cruising fast comfortably without chine walk or torque steer. Hole shot, and pulling power is not a concern at all. I don't have a jacking plate and I'm thinking a chopper prop would be the way I'd go, correct me if Im wrong. Any specific model, or blade number, diameter, and pitch suggestions would be great. Thanks!

Isaiah

Offline David CVX-16

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Re: Best Prop for Speed
« Reply #1 on: May 26, 2015, 01:30:43 PM »
Probably a 22" pitch Mercury Quicksilver chopper 13" in diameter. I sold one years ago without trying it. Next I would try a Laser II 22" pitch. I have for sale a new 22" pitch Mercury Quicksilver 2-blade bronze 13" diameter that I have never used, so I do not know how it performs.

An OMC SRX 23" pitch prop rehubbed for a Mercury might be faster than a chopper.

http://minneapolis.craigslist.org/ram/bpo/5036462659.html
« Last Edit: May 26, 2015, 03:06:02 PM by David CVX-16 »
David
87' CVX-16, 85' 115 HP Johnson, 58.8 MPH GPS w/ 23" SRX Prop

Offline Jerry

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Re: Best Prop for Speed
« Reply #2 on: May 26, 2015, 03:01:24 PM »
First things first.
Get either duel helm steering, or hydraulic steering and solid mounts.
Props you can play with, but Mercs will chine walk, and get it up so you don't need to worry about torque steer.
'72 Glastron GT160 Sport - Okie-Dokie
'63 Winner - Grandpa's Fisn-Bote
'63 Glasspar SeaFair Sunliner - Mischief Maker

Offline 74 Carlson the II

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Re: Best Prop for Speed
« Reply #3 on: May 26, 2015, 04:04:14 PM »
Any outboard motor with 115 hp or more will chine walk on a cvx16 or cv16, not just the mercs alone. It's all about the set up. Splash well mounted steering systems will produce steering torque from just about any motor at top speeds in stock form.
Steve
74 CV16 115 merc inline 87'
76 CV16 115 merc inline 76' 1150
72 CV19 outboard, no engine YET. Speed? (Unlimited)!!!!!!

Offline David CVX-16

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Re: Best Prop for Speed
« Reply #4 on: May 26, 2015, 04:16:44 PM »
In my opinion, for a 115 HP outboard on a CVX, duel steering, solid mounts, and raising the motor are all unnecessary. Nice, but not needed. My CVX with a 115 HP Johnson at 58.8 MPH is stable, no chine walk, very controllable in rough water, and the Teleflex no-feed-back steering has no pull to the right or left in the steering wheel.   

All this changes as the horsepower increases to 200 HP and speed to 65+ MPH.

David
87' CVX-16, 85' 115 HP Johnson, 58.8 MPH GPS w/ 23" SRX Prop

Offline CVX Fever

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Re: Best Prop for Speed
« Reply #5 on: May 26, 2015, 04:23:40 PM »
My CVX16 w/115 Merc ran 54 MPH and had zero chine walk. That boat was completely effortless to drive at that speed & steady as a rock. A chopper prop is a surface piercing prop and completely the wrong prop for your boat in stock form. Just throw on a 3 blade SS Laser II/Lightspeed(same prop) and that will get you about 98-99% of the way there where top speed is concerned.

1979 CVX18 "Back in Black"....someday!
1985 CVX18 " Only thing better than 2 CVX18's is 2 girlfriends!

Offline 74 Carlson the II

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Re: Best Prop for Speed
« Reply #6 on: May 26, 2015, 04:53:49 PM »
Most outboards have a trim limit, I have mine bypassed so I can trim a little further to squeeze out a couple  more mph with the motor sitting on the transom. The trim limit is there to help ppl not get out of control with chine walking on stock set ups.
Steve
74 CV16 115 merc inline 87'
76 CV16 115 merc inline 76' 1150
72 CV19 outboard, no engine YET. Speed? (Unlimited)!!!!!!

Offline 74 Carlson the II

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Re: Best Prop for Speed
« Reply #7 on: May 26, 2015, 05:30:18 PM »
Back to the question,  21 pitch or 22 pitch stainless steel.
Steve
74 CV16 115 merc inline 87'
76 CV16 115 merc inline 76' 1150
72 CV19 outboard, no engine YET. Speed? (Unlimited)!!!!!!

Offline David CVX-16

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Re: Best Prop for Speed
« Reply #8 on: May 26, 2015, 09:14:58 PM »
The motor in question is a 1978 115 HP Mercury. I believe that year the horsepower rating was still at the power head. And the RPM redline was 5,300 to 5,500. It would be a toss up between a 20 or 22 inch pitch prop.  Both the Laser II's and Choppers come in even numbered pitches. Real life testing is the answer.

With my CVX-16, I tested both a 20 and 22 inch Raker. Both were within the max RPM limit (5,500 to 5,700), but the 22 inch was faster. I attributed it to the HP peak on my 115 HP Johnson engine at 5,000 RPM. The 23 inch SRX runs about the same RPM as the 22 inch Raker, probably because of more slippage.   
« Last Edit: May 27, 2015, 04:38:09 AM by David CVX-16 »
David
87' CVX-16, 85' 115 HP Johnson, 58.8 MPH GPS w/ 23" SRX Prop

Offline Hyperacme

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Re: Best Prop for Speed
« Reply #9 on: May 27, 2015, 07:43:07 AM »
I would skip the older Merc and get a newer (1986 and above, I think) Merc or J/E.
The Merc's (after 1986) had prop rated HP, electronic ignitions, T&T built into the transom assembly.
Other members can help you with the best year J/E motors, but I think there HP rating changed from Power head to prop about the same time as Merc's.

With the older Merc your going to need a jack plate to lift your motor, because of the external T&T cyl. and clamp system.
You want to "Think through" your steering option before you do any thing ... What system do you have now ? ... Where is the cable coming out of your splash well ?  ...  Where will it connect to motor if lifted with or with out a jack plate ?
NFB will work well but you can't lift motor with out mod's to your splash well.
Hydraulic will work with any thing but costs $600.

If you go with the 1978 Merc, try a Lazer II in 20P or 22P ... The 22P worked the best for my set up, out of a bunch of props I've tried.
Hard to say what will work best for your set up, but you can find Lazer's on Craigslist for $150 to $200, and would be a good starting point.


Offline Jerry

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Re: Best Prop for Speed
« Reply #10 on: May 27, 2015, 08:41:28 AM »
Or you can convert it to short shaft, with Tilt Trim, like I did. I have over $8,000 in this one.

'72 Glastron GT160 Sport - Okie-Dokie
'63 Winner - Grandpa's Fisn-Bote
'63 Glasspar SeaFair Sunliner - Mischief Maker

Offline Hyperacme

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Re: Best Prop for Speed
« Reply #11 on: May 27, 2015, 08:58:45 AM »
You just need a sticker upgrade Jerry ...

MERCURY MARINE 1500 XS DECALS
http://www.ebay.com/itm/MERCURY-MARINE-1500-XS-DECALS-MERC-OUTBOARD-/310346693247




Offline Jerry

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Re: Best Prop for Speed
« Reply #12 on: May 27, 2015, 09:00:41 AM »
First I need the wrap. Jerry Sellner has one I want it!
'72 Glastron GT160 Sport - Okie-Dokie
'63 Winner - Grandpa's Fisn-Bote
'63 Glasspar SeaFair Sunliner - Mischief Maker

Offline Hyperacme

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Re: Best Prop for Speed
« Reply #13 on: May 27, 2015, 09:07:56 AM »
YA ... Putting louver's in a stock wrap might not be easy, if even doable ...

Offline 17ireid

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Re: Best Prop for Speed
« Reply #14 on: May 27, 2015, 12:56:22 PM »
Thanks for all the great information and suggestions, the outboard Im looking at came off of another CVX 16 and is a 20" shaft and tilt/trim, so I think as far as jacking plates go, I might be okay. Also as far as getting an 86 model there are some pretty slim pickings up in Maine as far as Mercs are concerned and this engine seems to be a really good deal.

I have the original rack and pinion steering. And the splash well mount is a 15ยบ mount. As I am running a setup of what my boat was stock, is hydraulic or double steering going to be necessary? I'm not looking to set speed records, I'm just looking to get the most stock speed potential out of my setup, as I plan to spend a lot of time cruising fast in upper 40's low 50's on some long straight river runs while maintaining close to top speeds. Instead of driving WOT all the time with a acceleration/torque orientated prop and getting mid 40's (Just guessing on the speeds here). Also, Chopper props just look awesome!
« Last Edit: May 27, 2015, 01:08:21 PM by 17ireid »

Offline Hyperacme

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Re: Best Prop for Speed
« Reply #15 on: May 27, 2015, 01:17:06 PM »
A NFB system will work fine with the 78 Merc.
Take as much "Slop" out of connections (steering cable to motor) as you can.

You have a tach ?
The Lazer II will be your best starting point.
Hard to say if a 20P or 22P will work best, you will have to try both to know for sure.
Some other brand / model / style might work better, but you don't know until you try them.

My CV with motor (prop rated 115 HP) all the way down on transom, 20P Lazer II, medium load of fuel and just me in the boat, got 50 mph/GPS.


Offline V153

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Re: Best Prop for Speed
« Reply #16 on: May 27, 2015, 02:25:01 PM »
It won't hurt anything to run a chopper. You just won't get the full benefit. As their designed to be semi-surfacing.

I ran a 90 Evinrude mounted as high as it would go on my 153. Best top speed with a 13 3/4 x 23 OMC SRX chopper was 54.8. It'd run about 2 mph slower with a 13 1/2 x 22 Lightspeed.

If memory serves me correctly RPMs were 6100 and 5900 respectively.

Only time I got a high temp alarm was running really hard for an extended time on a really hot day.

I'd imagine you ought to be able to swing either prop.

If you like the looks of choppers you'll love this: 30p Ron Hill Signature.

Here's a motor height chart too:
'81 C500_given away, bought back_75.1 mph
'81 Baja 15SS_140 Frankenrude_66.7 mph
'70 something SpeedCraft_(Allison 16R Clone)_69.0 mph
'79 CVZ19_given away
'71 V153_54.8 mph_wrecked


WALK TALL AND CARRY A BIG BILGE PUMP

Offline 17ireid

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Re: Best Prop for Speed
« Reply #17 on: May 27, 2015, 03:21:18 PM »
I don't have a tachometer, just fuel and speed the bare essentials haha. I do have a trim but I didn't get a tach or use the trim because I wasn't sure it was easily compatible with the Suzuki I've been working on since they are the original Mercury Quicksilver gauges. But I'm selling it because the parts are too expensive $500 for a High Pressure pump for instance. Also that is a super nice prop, I really like Cleavers but I think that would be less than ideal for my CVX. Also sounds like majority says the Lazer II is a safe good option I will definitely look into that.
« Last Edit: May 27, 2015, 03:25:06 PM by 17ireid »

Offline Jerry

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Re: Best Prop for Speed
« Reply #18 on: May 27, 2015, 04:45:48 PM »
You need to decide if you want to go fast, or half fast. If you want to go fast you need to do what I suggested. if half fast David's your guy.
'72 Glastron GT160 Sport - Okie-Dokie
'63 Winner - Grandpa's Fisn-Bote
'63 Glasspar SeaFair Sunliner - Mischief Maker

Offline V153

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Re: Best Prop for Speed
« Reply #19 on: May 27, 2015, 05:26:14 PM »
Ha ha ha!
'81 C500_given away, bought back_75.1 mph
'81 Baja 15SS_140 Frankenrude_66.7 mph
'70 something SpeedCraft_(Allison 16R Clone)_69.0 mph
'79 CVZ19_given away
'71 V153_54.8 mph_wrecked


WALK TALL AND CARRY A BIG BILGE PUMP