Reversing output full time

Discussion in 'Inboards' started by DogCavalry, Jul 24, 2021.

  1. DogCavalry
    Joined: Sep 2019
    Posts: 3,125
    Likes: 1,591, Points: 113
    Location: Vancouver bc

    DogCavalry Senior Member

    Most can be modified to allow LH input, giving LH output. My understanding is most will not survive long with RH input giving LH output full time.
     
  2. fallguy
    Joined: Dec 2016
    Posts: 7,695
    Likes: 1,707, Points: 123, Legacy Rep: 10
    Location: usa

    fallguy Senior Member

    I took out a LU once going about 20mph. The motor didn't kick up. The reef was largely unharmed.

    If you run in dangerous waters, leave one up.
     
    DogCavalry likes this.
  3. cracked_ribs
    Joined: Nov 2018
    Posts: 160
    Likes: 146, Points: 43
    Location: Republic of Vancouver Island

    cracked_ribs Senior Member

    Some Volvo legs can be switched in about two minutes. On mine there's a little cover plate on the back. You pull a single cotter pin, unhook a linkage rod, click the main rod the opposite direction, and pop the linkage back together. It will run left or right, no difference.
     
    DogCavalry likes this.
  4. cracked_ribs
    Joined: Nov 2018
    Posts: 160
    Likes: 146, Points: 43
    Location: Republic of Vancouver Island

    cracked_ribs Senior Member

    Oh and a good friend has lost two Merc 115 lowers on logs in the Fraser. No kicking up. Just drifting to shore with a truncated shaft.
     
    fallguy likes this.
  5. DogCavalry
    Joined: Sep 2019
    Posts: 3,125
    Likes: 1,591, Points: 113
    Location: Vancouver bc

    DogCavalry Senior Member

    Cool. I know engines can be reversed, but it's not free.
     
    Last edited: Jul 26, 2021
  6. cracked_ribs
    Joined: Nov 2018
    Posts: 160
    Likes: 146, Points: 43
    Location: Republic of Vancouver Island

    cracked_ribs Senior Member

    Well, it doesn't get much cheaper than doing it on old volvo legs. I don't know how long they retained this system but the 290s were good legs, and they had it.

    I have no idea what the guy in this video is talking about because I don't speak Italian which I believe this to be.



    But you can see him switch gears with that bronze lever thing. See how it's double sided? Reversing the input direction is basically just "connect the cable to the other side of the butterfly."

    Really not trying to sway you towards Volvo stuff - some people just hate it. I've been treated well by mine and you can find it cheap because everyone wants outboards. If you don't mind the weight, I'd stack up a pair of proven motors and a pair of 290s against pretty much anything; I think they're excellent legs. Mine is a 280 and has some quirks on account of its vintage, but it's bulletproof. But I always thought the 290s were really good as well. And despite what some people say I've found them to be pretty easy to work on, and parts availability has never been an issue.

    On the other hand...almost everyone wants outboards, including almost everyone who's got a proven motor in front of of a 290.
     
    DogCavalry and fallguy like this.
  7. DogCavalry
    Joined: Sep 2019
    Posts: 3,125
    Likes: 1,591, Points: 113
    Location: Vancouver bc

    DogCavalry Senior Member

    Thanks, CR. It's always worthwhile talking to you.
     
    cracked_ribs likes this.
  8. gonzo
    Joined: Aug 2002
    Posts: 16,836
    Likes: 1,734, Points: 123, Legacy Rep: 2031
    Location: Milwaukee, WI

    gonzo Senior Member

    Velvet Drives can turn both ways, but it depends on how the engine turns.
     
  9. gonzo
    Joined: Aug 2002
    Posts: 16,836
    Likes: 1,734, Points: 123, Legacy Rep: 2031
    Location: Milwaukee, WI

    gonzo Senior Member

    They don't need a modification. The pump in the front has two positions for LH or RH engines, it reverses the input and output holes. If you install an engine with the opposite rotation than what the pump is set, there will be no oil pressure and it won't go into gear.
     
  10. DogCavalry
    Joined: Sep 2019
    Posts: 3,125
    Likes: 1,591, Points: 113
    Location: Vancouver bc

    DogCavalry Senior Member

    But if you install a RH engine, then run it to give LH output (reverse) full time, I understand it will have a very short life.
     
  11. gonzo
    Joined: Aug 2002
    Posts: 16,836
    Likes: 1,734, Points: 123, Legacy Rep: 2031
    Location: Milwaukee, WI

    gonzo Senior Member

    The gear ratios in fwd and reverse are different, so the outputs would not match on a twin engine configuration. I can't see why the life would be so short. The fwd clutches have more discs than reverse so maybe wear faster.
     
  12. Nidza
    Joined: Nov 2016
    Posts: 107
    Likes: 29, Points: 28, Legacy Rep: 10
    Location: Belgrade, Serbia

    Nidza Senior Member

    As I recall, according to user/service manual and as owner of one older Velevet drive (72), reverse is implemented by planetary gears so you can even hear the louder noise from the gearbox when driving in reverse. I think those planetary gears are not build to withstand full torque (compared to direct connection of input and output shaft in forward). I think even the gear ratio in reverse is not the same as in forward. Yes, it is true that the direction of oil pump inside can be reversed, but only so that oil flows in correct direction, depending on engine rotation. If you rotate the pump incorrect, there will be no pressure to engage the clutches. Maybe I am wrong on some details, but user manuals for Borg Warner/Velevet drive is available online, so you can check for details. Therefore, as I recall, it is not intended to use reverse as main gear for extended time.

    I have just read one more time the first post and obviosly I have overseen the first sentance. My description of Velvet drive above is obviously missing your question, but I will leave it together with this comment instead of deleting it in case someone else find it useful
     
    Last edited: Aug 18, 2021
    DogCavalry likes this.
  13. gonzo
    Joined: Aug 2002
    Posts: 16,836
    Likes: 1,734, Points: 123, Legacy Rep: 2031
    Location: Milwaukee, WI

    gonzo Senior Member

    You are correct in your description.
     
  14. DogCavalry
    Joined: Sep 2019
    Posts: 3,125
    Likes: 1,591, Points: 113
    Location: Vancouver bc

    DogCavalry Senior Member

    So there really aren't any marine transmissions that can reverse output full time?
     

  15. DogCavalry
    Joined: Sep 2019
    Posts: 3,125
    Likes: 1,591, Points: 113
    Location: Vancouver bc

    DogCavalry Senior Member

    I could fab up something cheap that just reverses input. Seems like a niche product, but rebuilding an engine to make it turn backwards isn't exactly free, and reduces commonality in parts between a port and starboard engine. Obviously in high power setups, the engines need to turn opposite each other, but not in lower power to weight arrangements.
     
Loading...
Similar Threads
  1. halo64
    Replies:
    4
    Views:
    2,872
Forum posts represent the experience, opinion, and view of individual users. Boat Design Net does not necessarily endorse nor share the view of each individual post.
When making potentially dangerous or financial decisions, always employ and consult appropriate professionals. Your circumstances or experience may be different.