Prop?

Beretta1

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Jun 12, 2021
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I have a 2004 195 Captiva, 5.0 Mercruiser MPI engine. Any idea what factory aluminum prop came with it.
 
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achris

More fish than mountain goat
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May 19, 2004
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No (Mercruiser) engine package ever came with a prop, so there is no 'standard prop'.

You find the right prop by taking one out and running it and seeing what RPM you get at WOT... You then adjust accordingly.

Just run the numbers for a prop. Start with a 19" (Black Max) ans see how it goes. If it revs too high (more than 5,000) when fully loaded, then change to a 21"..

Chris.....
 

ThomW

Chief Petty Officer
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Aug 8, 2016
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615
Like Achris said....there is no magic prop pitch you can find for your motor. It all depends on boat, motor, the drive on the motor....
I would recommend going to mecurymarine.com and use their prop selector tool they have. You will need to put in the info on your boat, the motor, and the drive....then it will give you a few starting options as far as pitch and diameter go. Then from there, you need to adjust based on what you are getting at wide open throttle, versus what the motor is rated for.
 

Beretta1

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Thanks guys. I talked to a guy that worked at Rinker and he said the BMaxx 14 1/4 x 21 as well. Looking at an Amita3 Solas. Only difference is 14.3 diameter vs the a black Maxx 14.25. Wouldn’t that work just as well?
 
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airshot

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Like Achris said....there is no magic prop pitch you can find for your motor. It all depends on boat, motor, the drive on the motor....
I would recommend going to mecurymarine.com and use their prop selector tool they have. You will need to put in the info on your boat, the motor, and the drive....then it will give you a few starting options as far as pitch and diameter go. Then from there, you need to adjust based on what you are getting at wide open throttle, versus what the motor is rated for.
Just tried going there myself..."no longer availiable" is what keeps popping up
 

achris

More fish than mountain goat
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Thanks guys. I talked to a guy that worked at Rinker and he said the BMaxx 14 1/4 x 21 as well. Looking at an Amita3 Solas. Only difference is 14.3 diameter vs the a black Maxx 14.25. Wouldn’t that work just as well?
Solas props are infamous for being horribly inefficient.. I try to steer people away from them (yes that is from personal experience)... They are half the price for a reason...

Old Chinese proverb.. Good no cheap, cheap no good...
 

Beretta1

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Jun 12, 2021
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Solas props are infamous for being horribly inefficient.. I try to steer people away from them (yes that is from personal experience)... They are half the price for a reason...

Old Chinese proverb.. Good no cheap, cheap no good...
Gonna stay with the BM. Is there a 4b aluminum that you would recommend ? Don’t know if it would be any better than the 3b. Thanks for the info.
 

achris

More fish than mountain goat
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Gonna stay with the BM. Is there a 4b aluminum that you would recommend ? Don’t know if it would be any better than the 3b. Thanks for the info.
I had a 4 blade aluminum prop (before a reef ate it 😢). It was a Merc 'Alpha4'. Unfortunately Merc no longer make it, or any 4 blade alis. It was also the perfect size for my boat, 18", as 17" takes me into rev limit territory and a 19" is making the engine work just a bit harder than I want (also tends to fall out of the bottom of the power band at a slow cruise).. I've had to bite the bullet and go to stainless to get back into a 4 blade. I was shooting for a 17" (or 18" 🤞) Revolution4. Couldn't justify the cost of a new one, so scoured the secondhand market and ended up with a 17" 'Offshore' (predecessor to the Vensura, which is the predecessor to the Revolution4)....

Very very happy with the performance.
 

Beretta1

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Joined
Jun 12, 2021
Messages
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I had a 4 blade aluminum prop (before a reef ate it 😢). It was a Merc 'Alpha4'. Unfortunately Merc no longer make it, or any 4 blade alis. It was also the perfect size for my boat, 18", as 17" takes me into rev limit territory and a 19" is making the engine work just a bit harder than I want (also tends to fall out of the bottom of the power band at a slow cruise).. I've had to bite the bullet and go to stainless to get back into a 4 blade. I was shooting for a 17" (or 18" 🤞) Revolution4. Couldn't justify the cost of a new one, so scoured the secondhand market and ended up with a 17" 'Offshore' (predecessor to the Vensura, which is the predecessor to the Revolution4)....

Very very happy with the performance.
Probably just stay with the BM, due to cost, and, availability to try others. Hope it handles a tube, won’t be doing that much, but, will definitely have more than 2 aboard. Thanks
 

Scott06

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Probably just stay with the BM, due to cost, and, availability to try others. Hope it handles a tube, won’t be doing that much, but, will definitely have more than 2 aboard. Thanks
Michigan Wheel makes a Vortex 4 blade AL that is very similar to the Alpha 4.

I've run several of them over the years , just bought one for my new boat because the water level in low this year. They come in even pitches so If you had a 21" 3 blade black max I would run a 20" Vortex 4 blade, 19" => 18" etc. I found them a cheap way to build my knowledge base on prop swapping.
 

achris

More fish than mountain goat
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Probably just stay with the BM, due to cost, and, availability to try others. Hope it handles a tube, won’t be doing that much, but, will definitely have more than 2 aboard. Thanks
If you're pulling tubes/skiers drop 2" in pitch. IE, you'll need 2 props, or you'll hurt the engine...

Chris....
 

QBhoy

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Hi. This really depends what ratio you have. Some 5.0 mpi with an alpha have a 1.47 ratio. Some have a 1.62. If you have the 1.47…there is no way on earth you will run a 21” prop well. Probably not a 19” to the top of the rpm range either.
If you have a 1.62…you can likely run either of them. See if you can read the stamped ratio on the side of the upper drive
 

QBhoy

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I’d start with a 19” black max or a good used 19” stainless merc prop, if you get a good deal on it. You’ll always be able to sell a good quality 19” merc prop on. It will be somewhere between there and a 21” for all round use, I’d say. You may r”even turn a 23” in the bottom of the rpm range…but I wouldn’t recommend that. The 5.0 mpi is a little weak down low. Plenty of power up top usually…but being a little lazy down low with higher pitch…it won’t be too great with passengers or for general use. All the above is an assumption of course. Just sourced from knowledge gained with similar set ups.
 

Yegboats

Chief Petty Officer
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Feb 20, 2016
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513
I had a 4 blade aluminum prop (before a reef ate it 😢). It was a Merc 'Alpha4'. Unfortunately Merc no longer make it, or any 4 blade alis. It was also the perfect size for my boat, 18", as 17" takes me into rev limit territory and a 19" is making the engine work just a bit harder than I want (also tends to fall out of the bottom of the power band at a slow cruise).. I've had to bite the bullet and go to stainless to get back into a 4 blade. I was shooting for a 17" (or 18" 🤞) Revolution4. Couldn't justify the cost of a new one, so scoured the secondhand market and ended up with a 17" 'Offshore' (predecessor to the Vensura, which is the predecessor to the Revolution4)....

Very very happy with the performance.
Not sure why Merc got rid of the Alpha 4. Having 18/20 pitch available was nice. They replaced it with Nemesis/Spitfire 4bl alum odd pitch. 8m0055534/35/36
 

achris

More fish than mountain goat
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Not sure why Merc got rid of the Alpha 4. Having 18/20 pitch available was nice. They replaced it with Nemesis/Spitfire 4bl alum odd pitch. 8m0055534/35/36
I think they saw it as taking market from the stainless props.
 

Yegboats

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Feb 20, 2016
Messages
513
I think they saw it as taking market from the stainless props.
That makes sense. I think Turnung Point props have done a number on Merc prop sales. Rumor has it Brunswick boat brands with 150+hp and up mercs are shipping from the factories with stainless props. Almost all of Mercurys stainless prop part numbers are changing,they're coming with balancing weights in them and no longer include HubKits in the box.
 
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