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Thread: Outdrive ratio question

  1. #1
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    Outdrive ratio question

    Is the Bravo ratio determined in the upper gear set or the lower? How about the Volvo Penta 270s or 280s? Thanks, Bill

    1971 Donzi 18' 2+3
    1985 Eliminator 23' Daytona Offshore - Kevlar hull
    1988 23' Donzi CC F-23 with 250HP EFI Mercury OB
    1989 28' Team Warlock Offshore - single 548CID/600HP
    1990 23' Warlock Offshore - single 525HP
    Bill from Denison, TX - Lake Texoma

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    Bill on the Volvo 270 & 280 drive the ratio changes are made in the lower foot. Mark

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    Thanks Mark,
    I was almost positive of the Volvos, but I could not remember where the ratio is determined with the Bravo. Hopefully someone will chime in. Bill

    1971 Donzi 18' 2+3
    1985 Eliminator 23' Daytona Offshore - Kevlar hull
    1988 23' Donzi CC F-23 with 250HP EFI Mercury OB
    1989 28' Team Warlock Offshore - single 548CID/600HP
    1990 23' Warlock Offshore - single 525HP
    Bill from Denison, TX - Lake Texoma

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    Bill I called a friend and he said it's a combination of top and bottom gear sets on the Bravo drive.

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    Thanks guys. So if you install a 1.5 lower on a 1.36 ratio Bravo drive, you would end up with a strange ratio in between a 1.36 and 1.5? I am asking since I just bought an IMCO Extreme 1.36 drive with a conventional looking lower Bravo lower and want to install an IMCO SC lower foot on it. Thanks in advance, Bill

    http://www.ebay.com/itm/330688999797...84.m1497.l2649

    1971 Donzi 18' 2+3
    1985 Eliminator 23' Daytona Offshore - Kevlar hull
    1988 23' Donzi CC F-23 with 250HP EFI Mercury OB
    1989 28' Team Warlock Offshore - single 548CID/600HP
    1990 23' Warlock Offshore - single 525HP
    Bill from Denison, TX - Lake Texoma

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    Seems that the gearing in the lower of a Bravo is only different on Bravo III"S and just for diesel power, Gas appears to be all the same on all three Bravos.

    http://www.mercruiserparts.com/Show_...ND+DRIVE+GEARS

    http://www.mercruiserparts.com/Show_...G%28BRAVO+I%29


    http://www.mercruiserparts.com/Show_...28BRAVO+III%29
    machinist ,bore it deeper,ream it bigger, and lap it to a fine finish



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  7. #7
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    So it looks like the Bravo 1 drive is determined by the upper gear set while the Volvo Pentas are determined by the lower gear set. It looks like there were no alternative sets for the Bravo 1 lower gear set - just the upper which is apparently what determines the ratio. Correct? Bill

    1971 Donzi 18' 2+3
    1985 Eliminator 23' Daytona Offshore - Kevlar hull
    1988 23' Donzi CC F-23 with 250HP EFI Mercury OB
    1989 28' Team Warlock Offshore - single 548CID/600HP
    1990 23' Warlock Offshore - single 525HP
    Bill from Denison, TX - Lake Texoma

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