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  1. #1
    Join Date
    Mar 2008
    Location
    colorado river
    Boat
    c ray
    Details
    230 weekender- -310 sundancer
    Engine(s)
    454 Mercruiser w/Bravo III- -twin 7.4 mfi w/Bravo III's
    Posts
    660

    bravo III from alpha I swap

    hi; i am tired of problems breaking drive gears in my alpha behind a 454 in a '88' 230 weekender.
    i am looking to switch to a bravo III and am wondering if any one can help me with what prop pitch and gear ratio you might be using on your boats.
    most of our boating is at approximately 6000 ft elevation
    "88" 230 weekender ''2000" 310 sundancer

  2. #2
    Join Date
    Apr 2009
    Location
    PA
    Boat
    Sea Ray
    Details
    1999 260DA ShoreLand'r Galvanized
    Engine(s)
    5.7L EFI Bravo III
    Posts
    8,678

    Re: bravo III from alpha I swap

    You're aware there's a lot to do to make that switch, right? Among other things, everything on the outside of the transom needs to be changed.

    Is your current prop the correct pitch for the boat? If so, what is that pitch?
    Dennis
    1999 260DA 5.7L EFI B3
    2000 ShoreLand'r
    Past & Other Current Boats: Not enough room!
    "Exceeding your expectations since 1936"

  3. #3
    Join Date
    Jan 2009
    Location
    So Calif Offshore Islands
    Boat
    Sea Ray 1985 26' DA
    Details
    Furuno Navnet radar/chartplotter, fish finder, bait tank, 85 Gal main fuel tank, 75gal aux tank.
    Engine(s)
    Merc 8.1 Mag 375 HP / Bravo III,4 blade prop. 28mph at 3200rpm.
    Posts
    742

    Re: bravo III from alpha I swap

    The Gen 1 alpha's with V8 engines used 1.50 and now 1.47 GR in there drives.
    My 26' boat has the 1.47 GR drive

    Bravo 3 with a big block, fairly light boat 1.80 GR
    They gear them Bravo 3 drives down a little due to the power needed to spin the large surface area of twin props.
    Your 454ci has the power for the 1.80 GR
    The 2.0, 2.20 GR is for heaver boats smaller engines etc
    Prop shops will usually let you try out props B4 you buy
    They should have a good starting point also.

    If you want more top end speed.
    I think freshwater guys are into that
    It may be worth researching the Bravo 1 drive
    That drive comes in a higher GR (Faster top speed)

    A 454ci in a 24' boat should be able to push them taller gears nicely

    Cruising at low to moderate speeds, I think the Bravo 3 is the better choice.

  4. #4
    Join Date
    Jul 2005
    Location
    Prosser, WA
    Boat
    Sea Ray!! Duh!!
    Details
    23 year old CLASSIC 300 DA!!
    Engine(s)
    16 cyl, 700 cu. in./Alpha I's
    Posts
    2,558

    Re: bravo III from alpha I swap

    You might look at the drives available through Stern drive Engineering. They have a unit that is a direct replacement for the outdrive of the Alpha I. I don't know what kind of horsepower it can handle, but its a whole lot cheaper than switching to a Bravo.

    http://www.sterndrive.cc/
    1989 300 DA/Twin 350's
    1987 250 DA/454 Magnum :-( Sold
    Trailered in Spokane, WA
    Chevy Crew Cab DMax Dually

  5. #5
    Join Date
    Mar 2008
    Location
    colorado river
    Boat
    c ray
    Details
    230 weekender- -310 sundancer
    Engine(s)
    454 Mercruiser w/Bravo III- -twin 7.4 mfi w/Bravo III's
    Posts
    660

    Re: bravo III from alpha I swap

    thanks for all the replies guys.
    the other option i have would be to swap the 454 out for a 350 but to be honest i really have grown to like that BB thumping back there and have gotten as high as 3 mpg and can expect 2 mpg unless the conditions get rough.
    the A-I thats on there now is a 1.65 to one
    i run 17 pitch at 7000ft, 19 pitch at 6000 ft, and 21 pitch at 3600' and 1100'. this gets me 43 gps mph at all elevations with the biggest difference in the how quick she will come up on plane. it runs different rpms at the different elevations with different props but the speed has always been constant, i guessing this must be the speed for my hull and motor and while slower to get there at the higher elevations it is making power pretty consistently.
    stern drive wont sell or warranty a alpha I drive for a 454.
    i lunch a a-1 about every 20 hours and this last time it locked up and hydro locked my motor.OUCH. there easy enough to change and work on but i'm tired of getting towed in. if i could find one of the 1.32to1 or 1.50to1 heavy duty gear sets i might get it to hold up but i was just down at mead and tried and saw some B IIIs and liked every thing about them.
    i realize the cost involved and what all needs changed. so far the best deal i can find is going to be around $6500. drive, new transom assembly, raw water pump, and the props.
    as they come in the 1.80 2.0 and 2.2 ratios i didnt understand why so low ratios. i see now the props are all on the high side for pitch with 21 and 22 and 24 being the most popular??


    Last edited by garryowen; 05-11-2009 at 08:26 AM.
    "88" 230 weekender ''2000" 310 sundancer

  6. #6
    Join Date
    Jul 2005
    Location
    Prosser, WA
    Boat
    Sea Ray!! Duh!!
    Details
    23 year old CLASSIC 300 DA!!
    Engine(s)
    16 cyl, 700 cu. in./Alpha I's
    Posts
    2,558

    Re: bravo III from alpha I swap

    I ran a 454 Magnum on our 250 DA and it had the original Alpha I when we sold it in 2007. We NEVER had a problem with the drive.

    I wondered if SDE would have an option for for the 454 BB. I guess buying a new drive ever 20 hours makes the $6,500 look like a good deal. I think I'd just upgrade my boat and buy one with the Bravo already installed. Boats are cheap these days!
    1989 300 DA/Twin 350's
    1987 250 DA/454 Magnum :-( Sold
    Trailered in Spokane, WA
    Chevy Crew Cab DMax Dually

  7. #7
    Join Date
    Jan 2009
    Location
    So Calif Offshore Islands
    Boat
    Sea Ray 1985 26' DA
    Details
    Furuno Navnet radar/chartplotter, fish finder, bait tank, 85 Gal main fuel tank, 75gal aux tank.
    Engine(s)
    Merc 8.1 Mag 375 HP / Bravo III,4 blade prop. 28mph at 3200rpm.
    Posts
    742

    Re: bravo III from alpha I swap

    The Alpha Gen 2 is stronger then the Alpha 1
    Still would not risk it with the 454 ci

    I was told by a good mechanic that,
    What really kills the Merc drives is taking off too fast.

    It will flex the main shaft going from the lower unit to the upper unit. That will cause the gears /teeth to miss align in the upper unit and break due to the tq being applied.
    Taking off slow will help the drive.
    Under proping the boat will take some load off the gears also.
    That should help the Alpha live longer.



    I saw an adapter for changing to a Bravo not to long ago
    Maybe Alpha Gen 2 to Bravo?
    I think it said would not fit Alpha 1.
    Dont know if you have a Gen 2 being a 1988?
    May be worth doing a google search on

    Duoprops are suppose to give 3mph increase in cruise speeds.
    And 10% better MPG
    Last edited by Tail Chaser 661; 05-10-2009 at 11:59 PM.

  8. #8
    Join Date
    Mar 2008
    Location
    colorado river
    Boat
    c ray
    Details
    230 weekender- -310 sundancer
    Engine(s)
    454 Mercruiser w/Bravo III- -twin 7.4 mfi w/Bravo III's
    Posts
    660

    Re: bravo III from alpha I swap

    tail; that makes sense.every one i have failed has been the top gear set breaking teeth. i have had the motor out once changing rear motor mounts and looking for transom problems trying to solve this, so pulling it to change drive ect isht a problem. after looking i realy think the b3 is what we want. we are happy to cruise at 30 mph but like to do that speed for awhile as we boat flaming gorge, powell, and last winter mead. it takes awhile to get around and we like to get as far from the marinas as we can and then camp. every time i have lost a drive its been after we were on plane at 30 or so mph for over 30 minutes. i installed a drive shower on the last one thinking that might help, but still no luck


    well buying a different boat is a option. we have looked at a few. there is a dealer down in vegas that has a new 24ft 07 maxim carry over for 50,000 with a trailer. it has a 5.0 bravo 3. the fuel injection would be nice where we change elevations a lot. there were some things that killed the deal for us. aft bunk,4 ladder steps into cabin, 102" beam and dry weight is 700 lb more than our 230. i have a disabily and the steps both in the cabin and up to the swim platform and then no easy way to board from the side of the boat in to the cockpit made it not so good for us. that plus we realy like this old sea ray and the 96" beam. when we got it we had been looking at newer boats at the time but the cabin,cockpit,and helm lay out just seemed to fit what we wanted. the best way i can put it is like putting on a old comfortable pair of shoes that look like #### but man do the feel good compard to shiny new pair of dress shoes that hurt your feet after awhile.

    that said, we figured when we bought it we would try it for a while and trade if we didnt like it or repower and update what ever we needed to to keep it. my biggest concern in this is the weight it will add to stern of the boat and getting it proped right. it weights 6800 to 7000 pounds with the trailer with a full fuel load and lines and rigging. i tow with a gmc serra and a gmc yukon xl and am right at my tow limit with them now.

    dancer; the guy that had the boat befor me started messing with the gear ratios and had it in the shop 5 times in 7 years. the 2 years it wasnt in the shop the lake was low and the boat sat. it was golden before he started messing with it. then he would get ticked at the shops so its been in 4 different shops in 2 different citys.
    of coarse i did'nt find any of this out untill we bought the boat and started having trouble



    Last edited by garryowen; 05-11-2009 at 09:35 AM.
    "88" 230 weekender ''2000" 310 sundancer

  9. #9
    Join Date
    Jan 2009
    Location
    So Calif Offshore Islands
    Boat
    Sea Ray 1985 26' DA
    Details
    Furuno Navnet radar/chartplotter, fish finder, bait tank, 85 Gal main fuel tank, 75gal aux tank.
    Engine(s)
    Merc 8.1 Mag 375 HP / Bravo III,4 blade prop. 28mph at 3200rpm.
    Posts
    742

    Re: bravo III from alpha I swap

    garryowen,

    Seems I may have gave you bad info.
    I talked to someone that really did his homework running 454ci and 502ci engines on 26' Low to Mid 80's Sea Rays.

    He said they perform better with the 2.2:1 gear ratio or even bigger gear ratio with the 454ci. Then you run lots of prop pitch. 26" pitch on my boat with the 8.1 engine
    The person I talked to has the 502ci.
    He cruises 30 mph at 3000rpm.
    I assumed he was running 1.8:1 GR he runs the 2.2:1 GR

    Your lucky you have the big block.
    I just talked to a mechanic that just did a 8.1 repower. he pulled a 350 mag with only 20 hrs on it. A 24ft boat.
    That owners happy now.
    Check out www.perfprotech.com.
    They have fuel injection kits for the 454ci engines.

    Just thought I might add. Was told,
    Them 26' Sea Rays with the big blocks and bravo drives have been holding up since 1995/1996
    Last edited by Tail Chaser 661; 05-12-2009 at 03:19 AM. Reason: Added stuff

  10. #10
    Join Date
    Jan 2009
    Location
    Torch lake,Mich.
    Boat
    searay 26 sxl 1981
    Details
    1981 searay 26 sxl 2000 yukon xl 5.3 with a wipple charger
    Engine(s)
    twin 260's
    Posts
    89

    Re: bravo III from alpha I swap

    Gary, are you buying new drives,reman. or is somebody rebuilding them for you??? You have more drive problems than anybody I have ever heard of, bbc or sbc!!!

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