Reversing reverse??

Discussion in 'Inboards' started by jimisbell, Sep 12, 2006.

  1. jimisbell
    Joined: Jul 2006
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    Location: Gulf Coast

    jimisbell Junior Member

    I have a Perkins 4-108 driving a Velvet drive 2.57:1 transmission.

    The shift control is connected backwards, that is to say, pushing forward on the lever puts it in reverse and pulling back puts it into forward.

    In looking to correct this situation I find it was done because of space limitations and correcting it by moving the cable to the other side would be very dificult.

    So it occured to me that since I am using a LH rotation propeller all I would have to do is change the propeller to a RH rotation propeller and the control would be reversed.

    BUT two questions arrise:

    1) Does the Velvet Drive have the same efficency in both directions?
    2) And is the ratio the same in both directions?

    And finaly, since I usualy miss something, What did I not ask about that would make a difference?
     
  2. yotphix
    Joined: Sep 2006
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    yotphix Junior Member

    Are you sure that the LH rotation propellor isn't a mistake and the actual cause of the reversal?
     
  3. jimisbell
    Joined: Jul 2006
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    jimisbell Junior Member

    The engine is a LH rotation engine and unless the Velvet drive reverses the rotation then a left hadn rotation prop is correct. BUT...you make a point. I have yet to dive below the boat to see what prop I have. MAYBE the PO put a RH drive prop on it!!! I just bought the boat and had a diver inspect the bottom...but it didnt occur to me to ask him to check the drive direction of the prop.

    One thing that makes me think it is probably correct is that the throttle is ALSO connected backwards...i.e. forward is slow and back is fast. I brought it home on its botton 1400 miles and the two controls almost drove me to drink. The PO must have been dislyxic (sp?)
     
  4. Jango
    Joined: Aug 2005
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    Jango Senior Enthusiast

    With the motor running,take a look at the rotation of the output shaft from the transmission. If it is the same rotation as the motor, the trans is in forward gear. If the boat is NOT moving forward, but backing up, you have the wrong rotation prop.

    I'm told, running the trans in reverse gear to achieve forward motion for extended periods can damage the trans.
     
  5. Frosty

    Frosty Previous Member

    Not all gearboxes,-- ZF630 for instance. Its quite normal practise to run one geabox in reverse to achieve counter rotation. On my new yanmars with ZFs, I have 2.5:1 in forward and 2.54:1 in reverse This is normal it says so in the manual. However it is awkward as I have to run one engine just a tad faster than the other.
     
  6. Jango
    Joined: Aug 2005
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    Jango Senior Enthusiast

    I'm sure you are correct jack, but we are talking about a Velvet Drive Trans which should NOT be run in reverse to achieve forward motion.
     
  7. jimisbell
    Joined: Jul 2006
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    jimisbell Junior Member

    Well, then, I hope I was wrong about the prop because I have run it 250 hours that way! It will be a couple of weeks before I can check it out ..if I dont do it this morning....I will let you all know.
     
  8. Frosty

    Frosty Previous Member

    Simple just Google it.

    Borg warners direction is the same as engine rotation unless the identity number is followed by an asterisk*
     
  9. mainstreetmark
    Joined: Oct 2006
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    Location: Saint Augustine, FL

    mainstreetmark Junior Member

    I'm stuck in Jupiter Florida after 70 miles of running reverse with a RH prop.

    So, yeah, get the direction right.
     
  10. jimisbell
    Joined: Jul 2006
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    jimisbell Junior Member

    I must be running it in the right direction, i.e. LH Prop because I have put over 1500 miles on it since I bought it and its still going strong. On the 15th I will be hauling out to do the bottom so I will beable to check out everything then. I should just get into the water and check it as the water temp is still 83F today. But the water is not very inviting in color so I think I will wait until the its on the hard.
     
  11. FAST FRED
    Joined: Oct 2002
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    FAST FRED Senior Member

    Most times the shift controll has a "sea saw" connection to the shift cable.
    Simply move the cable attachment to the other hole setup.

    Even purchasing a new shifter setup would be far cheaper than a prop.

    FAST FRED
     
  12. stevel
    Joined: Aug 2004
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    stevel Lost at sea

    Which direction does the prop walk go when you reverse?

    If the stern walks left when you reverse, you have a right-hand prop. If it walks right, you have a left-hand prop. If it doesn't do either, your prop fell off:p
     
  13. jimisbell
    Joined: Jul 2006
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    jimisbell Junior Member

    Well now, that depends.....upon whether you have it in forward or reverse..... when you measure the direction of "walk". But mine walks to starboard when in reverse. Which is nice since I dock along a bulkhead starboard side in.
     
  14. stevel
    Joined: Aug 2004
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    stevel Lost at sea

    Hi Jim!

    I think I created some confusion by putting the information about being in reverse in the subject line, but not in the body. I'll get it edited in a minute here.
     

  15. jimisbell
    Joined: Jul 2006
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    jimisbell Junior Member

    No, you didnt create confusion, I created my own by not reading carefully.
     
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