all chopper info

[Toffy]

Hi everyone,

I’m gathering some info on chopper props.

I’ve found this very usefull link (via Markus, via Pyro) which shows the Mercury chopper history.
http://69.24.70.63/adamsdock/chopper.html
Too bad the pictures aren’t there anymore, a picture overview would be real usefull.
If someone could add pictures of the correct chopper types, your very welcome.

Also I’d like to know how these different chopper types perform.
I mean, why should I go for a small ear or big ear chopper ?
And what’s the performance difference between the 3 big ear types or isn’t their a difference except from the hub ?

Another question I have is about the weedcutters. I’ve read the weedcutters are the reason why they are called “choppers”.
However, some choppers had their weedcutters removed. Why is this ?
When you buy a chopper with weedcutters, will it always fit on the shaft ? Or is sometimes a weedcutter removal necessary ?
If one advertizes a chopper as “cut”, does this mean “removed weedcutters” ?

A chopper is a Mercury product, but there are a lot of chopper-style “round ear props” around.
Tricky question : should one look on the second hand market for the Mercury chopper or a round ear prop equivalent these days….


Thanks for sharing your thoughts and info.
Kind regards, T. :cheers:

[JohnR]

I picked a big ear up the other day and I'm no expert but what I've read says big ear carries a heavier boat like my Checkmate or maybe a Velocity better than a small ear which may be better suited for a smaller, lighter hull like a Hydrostream. Big ear makes more lift to make the hull run drier. I used that same link the other day to figure out what this one is. Some people believe removing the weed cutters helps performance, others disagree.

John

[David]

I've run big ear and small ear choppers on my SS2000. The big ears (2) had spooky handling. The bow was never still and i had to steer continuously. The two small ears I've run were great props for the money. I think the big ears have too much lift for my boat running solo. Very different handling on my boat.

[Toffy]

Thanks for the replies guys ! :thumbsup:

I've found some more info on chopper weedcutters on here :
www.screamandfly.com/showthread.php?214079-Merc-Chopper-weed-cutters-or-not
www.screamandfly.com/showthread.php?264889-Why-does-everyone-cut-the-weed-cutters-off-chopper-props
www.screamandfly.com/showthread.php?131215-Choppers-amp-weed-cutters

Does anyone have the original pictures that go with that "adamsdock link" ? They show the complete prop and hub detail.
That would by very usefull to put these up here.

Please share any thoughts on chopper props
Still learning here :smiletest:
Kind regards,
T. :cheer:

[cyhuff]

The weed cutters had to be ground off to work on my OMC V4 w/ 13 spline shaft.

[pyro]

"A4" 14" x 26 small-ear chopper. Note the protruding aft hub and skinny blades...

http://i42.tinypic.com/2dvo86q.jpg

"A4" 14.5 x 26 Big-ear chopper, recessed aft hub with no cut-outs (weedcutters have also been cut off this one)

http://i39.tinypic.com/35buqtz.jpg...

"A5" 14.5 x 24 big-ear chopper, recessed aft hub with cut-outs...

http://i43.tinypic.com/swbrwy.jpg

Another big-ear, a 28 pitch, with the weedcutters intact...

http://i39.tinypic.com/2nt40i.jpg

A5 30p "big-ear" Chopper, the odd-ball of the A5 series... recessed hub, cut-outs, but the blade shape of the small-ear props, and less diameter. Weed-cutters have been removed from this one.

http://i41.tinypic.com/dwcd1v.jpg

Later A62 series big-ear 30's have the wider 5" blades like other big-ears, and a flo-torq hub.

[cyhuff]

Hey Pyro, love the flame job on the 14 x 26 small ear. That might be the perfect size for my boat, as now I'm turning past 6500 with a 14 x 24 and 1.78 gears. Trace

[pyro]

I owned most of the props pictured. I did the flame job. Buffing wheel, masking tape, sandpaper. :)

[Toffy]

wow, great info Pyro, thanks man !!

Some more thoughts :
- As you owned all of those choppers, and I assume you've tested them all on your Hydrostream, is there one type that stands out ?
- Mercury advertizes their chopper II as "an improved version of the original chopper". I immediately believe in "an improved casting technique", but apart from that what could have been improved ?
- Those cut-outs on the later big ear A5 and the chopper II A62... what's their function ? Or is it just weight saving ?

:cheers:

[pyro]

Big ear choppers work good on heavy, conservatively-powered pad-vee hulls.
Small-ears work better in lighter hulls that need less bowlift.

I have 240 HP to work with-- on my boat I only use a Chopper when I have a big passenger load to carry.

The cutouts make it easier to reach the locking washer tabs.

The A62 (Chopper II) is only different because of the hub, and the addition of 30 and 32 pitch models with full-size blades.

[Toffy]

all questions answered, thanks !
Time to look for a chopper. 26P big ear, must fit 15spline Yamaha shaft
Chopper props don't sell second hand very often here in Belgium, so this could take a while T. :cool:

[Speed Jr.]

What are you going to run it on toffy? Hull/motor?

[Toffy]

Hi ! My boat is a Phantom 21ft with a strong running Yamaha 200hp V6 2stroke carb
Current prop is a Tempest plus 14 1/2" x 25P. I'm running close to 6000rpm.
:cheers:

[pyro]

The Tempest is a big, strong, load-carrying prop with lots of lift. If you like how it runs, the Chopper is probably a step backwards.

[Toffy]

Hi Pyro,

Yes it could be a step backwards, but it's the first prop I have and I want to know if there is something better out there and test it.
Fairly satisfied on how it runs with the tempest plus. However :
- chinewalk above 100kmh
- hole shot could be better (I'm struggling with my engine height versus vent plug types, I have no low water pickup so i can't go too heigh)
- I feel like topspeed could improve using a 26pitch in stead of 25pitch
- I feel like a over the hub exhaust prop could be better (going to test a 26P Seebold cleaver for that matter, but I don't expect whopping results as it gives off course sternlift)
- I feel like a bit more bowlift is needed

:cheers:

[bulldogdaddy]

Toffy,i came across a 26 big ear merc offshore cut that was hubbed for an omc,over the hub btw.it is the best handling prop I've run yet.no chinewalking at all

[Markus]

all questions answered, thanks !
Time to look for a chopper. 26P big ear, must fit 15spline Yamaha shaft
Chopper props don't sell second hand very often here in Belgium, so this could take a while T. :cool:

I have a 24 and a 28, which are at least in Europe, but no 26...

[JohnR]

Modified to fit OMC means it should still fit straight on a Merc. I seem to remember reading Yammie is the same as Merc.

[Toffy]

I seem to remember reading Yammie is the same as Merc. yup :cool:

Can someone explain what these are : "Offshore or an allison cut chopper"
Are these different ways to remove the weedcutters ? What does it look like ?

Thanks !

[pyro]

Here's a good example of this type of cut. The leading edges have been trimmed, the cutters and leading edge of the blade root have been ground away, and some mild cup has been added. Hoss makes some nice props that are close to this style.

http://i42.tinypic.com/30t0ta9.jpg

[Toffy]

Thanks Pyro ! :cheers:

[mariawhitetrash]

Toffy have you tried Nico at Bernico? They have loads of props

[Toffy]

Hi ! Thanks for that advice. I already talked to him and this seems definately the way tho go. But for now I don't want to go that way, as after a proptest session I would feel obligated to buy a new prop from him. Nothing wrong with that off course but I just don't want to spend that kind of money. It's still a hobby, and there must be a good second hand prop out there for me that can outperform my Tempest Plus :cheers:

[dnelson964]

Hi ! My boat is a Phantom 21ft with a strong running Yamaha 200hp V6 2stroke carb
Current prop is a Tempest plus 14 1/2" x 25P. I'm running close to 6000rpm.
:cheers:

You have been given excellent advice on choppers but from reading what boat, motor and prop you have run and what you want I recommend you try either a Yamaha T1 or M in 26 pitch or a Turbo lightning 26. They will all give you more overall lift, including stern to help your speed, give excellent handling and no chine walk. I have run every prop you have mentioned on here.

[Toffy]

Nice advice from someone who've tried em all, thanks ! I'll surely try them when I get the chance. :up:

[Toffy]

Hi all,

I've found some more info and pictures on different cuts.
It seems that a chopper with standard blades can be cut to different styles...

http://www.sdspropshop.com/Prop_Work/Prop_Work.html

Why would you chose for a specific style of cut ?
Could one say a certain style always leads to a specific handling of the boat ? eg. less chinewalk, more bowlift, more top-end...

Thanks for sharing info,
Kind regards, T. :cheers:

[pyro]

That's Steve... He's a vendor on this forum.

[Toffy]

You have been given excellent advice on choppers but from reading what boat, motor and prop you have run and what you want I recommend you try either a Yamaha T1 or M in 26 pitch or a Turbo lightning 26. They will all give you more overall lift, including stern to help your speed, give excellent handling and no chine walk. I have run every prop you have mentioned on here.


The Tempest is a big, strong, load-carrying prop with lots of lift. If you like how it runs, the Chopper is probably a step backwards.

Hi ! I did some fun proptesting this weekend :
- Tempest Plus 25P : 115km/h @ 5900rpm
- Chopper 28P : 108 km/h @ 5800rpm, too much ventilation, takes long to get on plane and when it starts to pull. better handling at speed and also shorter cornering compared to the tempest plus, similar bowlift though where I expected more...
- Cleaver 26P : never got on plane... :p :p didn't expect it to be that bad. I probably need more engine height for that cleaver but I don't have a low water pick up.

Still got some testplans :
chopper 26P (It'll teach me if I must let go 3blade over the hub type of props)
Pro ET 26P (I expect great things from this 4 blade prop)

for the longer future :
Trophy Plus (should accelerate fast, curious about top speed numbers)
Turbo lightning, Yamaha drag, T1, M.... if I can find them

Kind regards,
T. :cheers:

[NosBoss]

The problem you have with getting on plane has to do with the prop venting too much. If your exhaust was relieved somewhere other than the propshaft it would get on plane much better. I can't get my baja to plane out with an over hub prop cause it just vents real bad.

[pyro]

With a true surface prop, when the boat initially lays down on plane, there is a great amount of slip as the prop first meets the surface-- the prop is trying to grab more water than the surface can provide, as the boat's speed hasn't yet caught up with the speed of the spinning blades. Relieved exhaust will control the initial rev-up when you first hit the throttle, but it can't do much to control the planing slip that occurs afterward. The best approach is to give full throttle at first, so the boat has some momentum when it lays down, then feather the throttle to allow the water to fall into the blades before getting back on the throttle again. With some props, you have to just stand on the rev limiter until it catches the water.

Props such as the Trophy have a heavy trailing edge with lots of cupping cast into the blade. These props will have less planing slip, even when you run on the surface.

[Toffy]

Thx for those replies NosBoss and Pyro ! :up:
I just got the advice from my friend who has exact same boat, engine and prop (though his is a ChopperII) too lower my engine about 1" and redo the test with the chopper 28P.
This should give it more bowlift and therefore better topend, less ventilation and therefore better holeshot... Surely gonna give feedback on that. Engine height could turn out to be just that critical... :cheers:

[Toffy]

Info on 'butterfly cut' of a chopper prop ->
http://www.screamandfly.com/showthread.php?299212-Mercury-Props&p=2694049 (http://www.screamandfly.com/showthread.php?299212-Mercury-Props&p=2694049#post26)