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Max RPM on Bravo drives

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Max RPM on Bravo drives

Old 10-15-2014, 01:20 PM
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Default Max RPM on Bravo drives

This may not be an issue but I've read a couple post (not here) that the Bravo drives have a maximum rpm. This came from a discussion that Merc wants to keep the prop rotation between 2300 to 2500 rpm. I'm looking into going from a Bravo 3 with a 2.0 ratio, to a 1.81. Anyone hear of anything regarding this?
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Old 10-15-2014, 01:36 PM
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You would just need to change the upper gear set... the 1.81 B3 is the same as the 1.36 B1 gear set ( 27/29 tooth count)
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Old 10-15-2014, 01:44 PM
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Originally Posted by JaayTeee View Post
You would just need to change the upper gear set... the 1.81 B3 is the same as the 1.36 B1 gear set ( 27/29 tooth count)
Thanks and I'm sorry, must not have asked the question correctly. Can props be spun faster then 2500 or better yet 2700 RPM without damaging the drive or prop? Is there a max RPM for the drives?
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Old 10-15-2014, 02:19 PM
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Most people on here spinning their engines between 4800&6000,so I don't think that is correct.
Hope this helps. Ken
Just noticed you said bravo 3, no idea sorry

Last edited by buck35; 10-15-2014 at 02:23 PM.
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Old 10-15-2014, 02:30 PM
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Originally Posted by buck35 View Post
Most people on here spinning their engines between 4800&6000,so I don't think that is correct.
Hope this helps. Ken
Just noticed you said bravo 3, no idea sorry
Thanks, what I read was for any bravo drive (1, 2 or3). It's probably not an issue but want to make sure before I buy a new drive. Currently turning 5200 with a 2.0 which gives me a prop rpm of 2600. If I go to a 1.81 that will bring it up to 2872 rpm
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Old 10-15-2014, 04:56 PM
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I was kind of under the impression that rpms are a bravos friend to a certain point. Like 6000rpm input rating on say a cat with 1.36 drives will be over 4400 prop rpm. I don't think id concern myself over a few hundred rpm even being a b3. Granted there's going to be more strain but i don't think it'll be the difference of lasting 10years vs exploding the first run. If they couldn't handle the rpm they pry wouldn't offer it in that ratio. Just my opinion
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Old 10-15-2014, 05:06 PM
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Originally Posted by AllDodge View Post
Thanks, what I read was for any bravo drive (1, 2 or3). It's probably not an issue but want to make sure before I buy a new drive. Currently turning 5200 with a 2.0 which gives me a prop rpm of 2600. If I go to a 1.81 that will bring it up to 2872 rpm
Half a kazzillion boat owners with 1.5 Bravo Drives are spiining there engines 5000-5200 rpm even with black motors. Example: 502MPI's are propped to run 5000-5100 rpm with 1.5 drives.

A higher # gear turns the prop slower. A lower # gear turns it faster.

Schit, 10 kazzillion 1.5 Alpha propelled boats have there engines spinning to 5k also.

Thinking quickly outloud, maybe those propspeed #'s you brought forth are help for boat manufacturer's to gear there boats ? Or maybe further, a certain type of boat (Express Cruiser vs performance boat vs.........)

I dunno...throwing it against the wall.
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Old 10-15-2014, 05:48 PM
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Appreciate it much guys. Couldn't find anything but one thread and could not find any backup. Either way just trying to verify before I drop the coin. If 6000rpm cats are running 1.36 (prop at 4411rpm) then that tells me there should not be an rpm issue. Wonder what the max rpm is for any bravo drive, 10K ? Wouldn't be a bad thing to know.
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Old 10-16-2014, 12:55 PM
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I spin my XRs with 1.36 gears and 35p 5 blades on a 36 cat 6200rpm all the time. Let it turn.
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Old 10-16-2014, 01:01 PM
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Originally Posted by Cobra100+ View Post
I spin my XRs with 1.36 gears and 35p 5 blades on a 36 cat 6200rpm all the time. Let it turn.
Thanks, sure appreciate put this one to bed
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