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Alumacraft 185 Competitor 150 HP Prop? - Page 3 - Walleye Message Central
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  #21  
Old 09-21-2020, 01:38 PM
EasternWashingtonBoater EasternWashingtonBoater is offline
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Please verify what I'm saying, as I have no experience with Suzuki, but being that this thread is interesting, I looked around.

Avoid Solas, however - their Stainless is as good as another's aluminum.

I see right away two quality options; a Mercury or PowerTech prop.

For Mercury, you'd adapt it to your engine with the Flo-Torq hub
https://www.amazon.com/QuickSilver-8.../dp/B000XBGWBM

For Power-Tech, a Cushion-Lok hub
https://www.ptprop.com/cushion-lok-drivers.html

As for Props, you can scan eBay or the classifieds for something you think will work. Power-Tech has many different props that are interpretations of others. There's a new REV-class they're going to introduce that should substitute for a Mercury Rev-4 prop.

I think you're getting the right picture, though. You need a compromise between diameter and pitch, along with the motor positioning on the boat.

I find it interesting you're able to use such a large diameter prop at 19 pitch and get up to 6000 RPM. You could consider even a more pronounced cupping for a 19 inch prop, or as you say, try a 20 inch prop as it'll be faster if you can still spin it. Or go down in diameter for the 21 inch prop, to a 14 1/5 or even 14 inch.

My Yamaha F200 really likes the Quicksilver 21 13 7/8 prop on my 19' Alumacraft - I currently have a Tempest Plus 19 on it and have been disappointed in its top end performance.

You can browse at the PowerTech prop site and see the differences between their prop types and maybe you can choose one that's available on eBay that matches what you think you'll need.
https://www.ptprop.com/e-class-propellers1.html
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  #22  
Old 09-21-2020, 08:04 PM
Slabdaddy
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Thank you posters for your thoughts and replies. I will stay away from Solas and I am glad i asked. My other thought was to try to find a prop with 1 14.5" diameter and 21 pitch; this would be a 1/2" smaller diameter and it makes sense to me that the prop would spin a bit faster and RPMS would hopefully increase into the mid-5K (was 5,200 with the 15 x 21 prop). At WOT, the motor would not spin the prop any faster even with some throttle left in the tank. Would a half inch increase RPMs and top end speed? Is it worth the gamble to buy a 14.5 x 21 or a 15 x 20 IF I can find one? The online prop exchange thing is probably something worth looking into. Would be nice to have the peace of mind knowing that you aren't locked in if the prop is not correct. Thank you everyone and tight lines all!
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  #23  
Old 09-22-2020, 07:31 AM
DW DW is offline
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a 14 to 15” diameter with a 20 to 21” pitch would be about right for a df150 with the 2.5:1 gear ratio. However it is way too much prop with the 2:1 gear ratio.

The Suzuki web page indicates 17 or 19” pitch with the df150 version with the 2:1 ratio.

You should not settle for RPM in the mid 5000 RPM range or your motor will under perform. You should not settle for a set up that delivers any less than 6000 RPM at WOT.

However, since it is appears you have not set the motor height correctly you are wasting your time and money investing in another prop. You boat is underperforming and there is no alternative but go through the steps to fix it.
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  #24  
Old 09-22-2020, 12:36 PM
Slabdaddy
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Thank you DW. So if it was you, you would start by lowering the motor from the second to the third hole? What will the primary benefits be? Will this likely increase top speed while slightly reducing RPMs? Sorry for the stupid questions, I just want to be sure I understand before I start moving a 500lb motor. The 19 pitch may be the right prop afterall. If RPMs remain at or above max after lowering, maybe I need to try the 15 x 21 prop again to see if my RPMs and speed increase. Thinking out loud here....thanks again for the inputs. I am considering lowering the motor after this discussion.
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  #25  
Old 09-22-2020, 06:44 PM
DW DW is offline
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First, I recommend you take a picture of your anti ventilation plate while the boat is on plane, and post it so we can see it.

If you can’t do that, have someone ride in your boat who knows what they are doing to observe so they can determine if your motor is too low. The antiventilation plate must be out of the water when your bost is on plane.

If that is not possible, then arrange to raise (not lower) your motor by one hole. That will raise speed. If that position is too high your prop will tend to ventilate and over rev particularly if you make sharp turns.

You have to get the motor height right before making prop choices.
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  #26  
Old 09-23-2020, 08:22 AM
Slabdaddy
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Thank you again DW; I did some additional online research and I consistently read the anti ventilation plate should be about parallel to the keel when trimmed down and paralell with the transom. I tested this theory in my shed and found that the anti-ventilation plate is just slightly above the keel but almost even. Moving the motor up may not make sense; however, I will be observing the plate to see if it is out of the water when I am on plane as you recommended. I may have a guy who has several different props to test and we are thinking of increasing pitch to a 20 or 21 and reducing diameter to less than 15". this may be the best of both worlds. If that does not work, we will likely raise or lower motor depending on what we see on the water. I have a feeling that I am getting closer to solving this riddle! Any other recommendations or real life applications/experiences would be appreciated! Thank you all and tight lines!
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  #27  
Old 09-23-2020, 01:01 PM
jjy jjy is offline
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Quote:
Originally Posted by DW View Post
First, I recommend you take a picture of your anti ventilation plate while the boat is on plane, and post it so we can see it.

If you can’t do that, have someone ride in your boat who knows what they are doing to observe so they can determine if your motor is too low. The antiventilation plate must be out of the water when your bost is on plane.

If that is not possible, then arrange to raise (not lower) your motor by one hole. That will raise speed. If that position is too high your prop will tend to ventilate and over rev particularly if you make sharp turns.

You have to get the motor height right before making prop choices.
I agree having anti cav plate above water at cruise is ideal on most boats, but not on Alumacrafts gull wing hull. Alumacraft has a very sharp v at stearn which I believe causes an issue with having anti cav plate above water line. In my experience with 205 spt, I have tried almost every engine mounting position, 2,3, and 4. Every time I visually look at cavitation plate, it seems low even at highest motor position 4. I am currently back to position 3 from 4. I may move back to position 2 after I test my next prop. Position 4 gave me a better cruise efficiency at the expense of less grip in waves, higher slip at top speed, and cavitation when turning. This is my experience running both the stock saltwater series 2 and bravo fs props. Unless your 185 runs different than my 205, I would not recommend a 4 blade stern lifting prop. A 4 blade gives a very level ride but causes bow spray rails to be pushed down and results in a wet/rough ride. A jack plate would be ideal but warranty says no to that.
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  #28  
Old 09-23-2020, 05:32 PM
DW DW is offline
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Quote:
Originally Posted by jjy View Post
I agree having anti cav plate above water at cruise is ideal on most boats, but not on Alumacrafts gull wing hull. Alumacraft has a very sharp v at stearn which I believe causes an issue with having anti cav plate above water line. In my experience with 205 spt, I have tried almost every engine mounting position, 2,3, and 4. Every time I visually look at cavitation plate, it seems low even at highest motor position 4. I am currently back to position 3 from 4. I may move back to position 2 after I test my next prop. Position 4 gave me a better cruise efficiency at the expense of less grip in waves, higher slip at top speed, and cavitation when turning. This is my experience running both the stock saltwater series 2 and bravo fs props. Unless your 185 runs different than my 205, I would not recommend a 4 blade stern lifting prop. A 4 blade gives a very level ride but causes bow spray rails to be pushed down and results in a wet/rough ride. A jack plate would be ideal but warranty says no to that.
That is weird.

Most boats have a sharp V at the transom. For example, I have 17 degree deadrise at the transom. A few boats have stepped hulls or pads like the IPS. A sharp V can cause turbulence that may induce ventilation but it is a situation most boat owners encounter.

I wonder when some owners run out of holes to raise the motor if the boat was prepped improperly and the motor mounts drilled too low.
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  #29  
Old 09-23-2020, 07:04 PM
Slabdaddy
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JJY, in your opinion, do you think it is worth the effort to raise up one hole (from hole 2 to hole 3)? I am considering it. I don't think it needs to go down as the anti-cavitation plate is near the surface based on my test run earlier tonight on a local lake. I hit 42.7 mph with my son and I in the boat (about 320 lbs total), regular gear and under half tank of fuel. My RPMs are at about max (6,000). I am running a 19 pitch and am considering a 20 pitch to gain maybe a few mph. Several other alumacraft performance reports for this model and similar models with a yammi 150 push 48-50 mph. Some of those had the motor mounted in hole 3. I would be happy with 45-46 but am not going to lose sleep over it if I don't achieve. It just seems like there is a bit of drag someplace even though the plate in near the surface and I want to maximize efficiency for performance and fuel usage. And yes, I have the motor trimmed up properly once on plane. Confirmed today with my dealer that my motor has the standard 2.50.1 Suzuki gear ratio and not the 200.1. I absolutely love the boat and motor, just trying to dial in. Thanks all and Tight Lines!
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  #30  
Old 09-23-2020, 07:29 PM
DW DW is offline
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“ my dealer that my motor has the standard 2.50.1 Suzuki gear ratio and not the 2.1.”

so, disregard my comments about pitch.
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