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Thread: Failing Flex Drive

  1. #1
    Join Date
    May 2011
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    AU
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    Default Failing Flex Drive

    Hi,

    Overall I am happy with my Impulse, except that I have had several flex drives fail.
    They are getting hot right on the bend of the brass tube and they eventually get so hot that they melt and break. Each time I loose the shaft, prop and chew up the teflon tube.

    After my second one failed I spoke to my LHS and they just said that I did not lube the drive correctly. I explained that I am not a noob, and I have been FE boating for about 3+ years with about 6 boats, therefore I do appreciate the need for satisfactory lubrication of the drive system. I believe that it is the poor quality of the stock flex; therefore I do not really want another stock replacement.

    I know OSE sell a better quality replacement which I am thinking of purchasing, but it is quite expensive to ship to Australia so I would like to know if anyone else had had a similar problem before I potentially destroy another one.

  2. #2
    Join Date
    Apr 2007
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    Default

    Are you running a stock setup? What are you using to lube and how often?
    Have you tried running without the teflon?
    Government Moto:
    "Why fix it? Blame someone else for breaking it."

  3. #3
    Join Date
    May 2011
    Location
    AU
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    Default

    I have been running the stock setup (motor, ESC, Prop) on 6S. The electrics appear to be all okay with the 6S so far.

    I have though about running without the teflon, but I was expecting it was there for a reason (ie. reducing noise and providing a smooth surface for the drive line). If I need to upgrade the flex drive to 3/16" then I will have to run without the teflon ;-).

    I have tried Grimracer cable grease, and more recently I have tried something thinner to try to reduce drag. As am also a cyclist so I have tried a thin viscosity chain lube on the flex drives which appears to work well on all my other boats.

  4. #4
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    Default

    I would go back to the grease. Make sure there is no binding in the drive line. Do you have adequate clearance between the drive dog and the strut? Can you post pics of the inside and back end (side and back view)? Sometimes the teflon gets heated and can cause the binding. Have you ever replaced the teflon liner?
    Government Moto:
    "Why fix it? Blame someone else for breaking it."

  5. #5
    Join Date
    May 2011
    Location
    AU
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    The drive line was quite free. There is plenty of clearance between the strut and the drive dog (about 5mm). I believe this is due to the factory flex shaft being a little too long. Each time the drive line failed it tore up the telfon so it has been replaced.

    I understand what you are saying about the teflon.... it gets hot and binds the flex drive, which causes more heat and more binding etc.
    I have read that some guys on this forum are running without the teflon.....are you?

    It is a bit difficult for me to take photos as the drive line is at the bottom of the lake :-)

  6. #6
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    Default

    LoL. Actually I meant the boat. I have a couple with no teflon, One with and a few where the teflon is only about one to two inches on each end. More for sealing than anything else.
    Are there any sharp bends or dings in the stuffing tube?
    Government Moto:
    "Why fix it? Blame someone else for breaking it."

  7. #7
    Join Date
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    Location
    AU
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    Default

    I shone a light down the stuffing tube tonight to check, and there are no sharp bends or dings. The factory bend is quite smooth, I could actually see the light at the other end.

    Are there any negatives with running without the teflon tube?

  8. #8
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    Not really. A large number of members run their boats without the liner. Just remember to really grease the crap out of the cable. Put a piece of silicon tubing over the motor end of the stuffing tube to act as a seal. This will reduce the amount of water that "walks" up the drive line. When running you boat, stay clear of weeds, turtles, alligators, swimmers and other things that might get caught by the prop. Speaking of which, what size is your prop?
    Government Moto:
    "Why fix it? Blame someone else for breaking it."

  9. #9
    Join Date
    Jun 2012
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    MA
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    Default

    Doesn't the impulse need a liner? Otherwise there is a gap between the strut and brass tube where the exposed cable would be? Also he would need a larger cable to run without liner I think?

  10. #10
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    Quote Originally Posted by Heaving Earth View Post
    Doesn't the impulse need a liner? Otherwise there is a gap between the strut and brass tube where the exposed cable would be? Also he would need a larger cable to run without liner I think?
    Good Catch! You may be correct. I should have looked at the hardware of the impulse a little closer. My suggestions are for most others with a common strut configuration. My bad.
    But really do need those pics to be more accurate in troubleshooting this problem.
    Government Moto:
    "Why fix it? Blame someone else for breaking it."

  11. #11
    Join Date
    Jul 2012
    Location
    ab
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    Default

    Mine had the same problem running on 6s. I took out the Teflon and started running the upgraded bigger shaft Steve sells here on OES. Haven't had a problem since. Just make sure you order the proper coupling when you order the bigger shaft the Proboat one won't work.

  12. #12
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    May 2011
    Location
    AU
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    Default

    As requested I have attached some photos of the stuffing tube.
    It appears suitable to not use the teflon tubing.

    Copy of DSC01171.JPGCopy of DSC01163.JPGCopy of DSC01165.JPGCopy of DSC01166.JPGCopy of DSC01168.JPG

  13. #13
    Join Date
    May 2013
    Location
    Va
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    1

    Default

    Do you have a list of the part numbers that you used. Basically everything that is needed to convert over to the larger shaft. Thanks

  14. #14
    Join Date
    Nov 2009
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    CA
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    Default

    Try adjusting the height of the motor-- if it is not centered just right it can cause the flex to bind on the stuffing tube.
    Chief

  15. #15
    Join Date
    Sep 2011
    Location
    MN
    Posts
    103

    Default

    The od of my stock flex drive is .150 and the ID of the stuffing tube is .150.
    I took a .166 drill and drill reamed the tube from each end.
    Works great. Roll the tube on the counter to straighten it out prior to ream.

  16. #16
    Join Date
    Jul 2012
    Location
    Ok
    Posts
    160

    Default

    I have well used V1 I boat I bout used used and the stock shaft snapped. When I received the boat I took the shaft out and it looked like the grease had been left in there for a while.
    I cleaned it up the best I could but after about 4 runs at 60 mph it snapped and to the bottom my prop.
    58" Venom Segad-48" Prather Deep Vee-41" Dumas 1/8 Hydro-34" Saga C1-32" Venom KOS P1-31" Pro Boat Impulse V1

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