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Thread: Aquacraft MiniMono Drive Shaft keeps coming loose

  1. #1
    Join Date
    Oct 2011
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    AZ
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    244

    Default Aquacraft MiniMono Drive Shaft keeps coming loose

    I got my Minimono a month ago. Unfortunatley, I have not been able to enjoy it as the wire drive shaft comes loose from the coupler at the engine within 2 seconds of entering the water. I followed the instructions, tightened easch side progessively and no luck. I even tried epoxy! - No luck. I guess my next try will be to solder the wire shaft to the coupler. Has anyone else had this problem and are they any solutions, thoughts Ideas?

  2. #2
    Join Date
    Oct 2011
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    CA
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    6

    Default

    Call customer support and get another one. Its not worth not being able to use your boat. I bought mine from tower and they are A+ at getting things out if there is a problem.

  3. #3
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    Oct 2011
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    Default

    Thanks. I will do that.

  4. #4
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    Aug 2011
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    Ab
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    Default

    I had this problem with mine after a few packs through it and pulling the shaft at least once for lubing .

    Took some playing around with the set screws to get it right .
    I may swap the set screws out for different ones .They seemed a little iffy .

  5. #5
    Join Date
    Nov 2010
    Location
    NY
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    Default

    All 3 of mine came with a spare prop, nut, and wire drive. I flat spotted my wire drive and use locktite on the screws. The screws were difficult to get all the way seated. Make sure the screw is seated by holding the coupler and trying to spin the prop, you will feel when the first set screw engages, then tighten the other one against the first one.

  6. #6
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    Oct 2011
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    Default

    Thanks for the info!

  7. #7
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    Nov 2010
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    NY
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    Default

    No problem. I also lined up the flat spots I made with the ears on the drive dog so I can tell where the flat spot is just by looking at the drive dog.

  8. #8
    Join Date
    Jan 2011
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    IN
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    Default

    I nearly lost my boat today. Lost the entire propshaft. Boat was dead in the water while slowly sinking due to water entering the stuffing tube. Luckily I had another boat there to push it shore.

    Not happy. But I will try the good suggestions in this thread.

  9. #9
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    Jan 2011
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    IN
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    Default

    After further inspection, it turns out the set screws were in place. The drive wire broke at the coupler.

  10. #10
    Join Date
    Nov 2008
    Location
    IL
    Posts
    662

    Default Just Thinking

    I keep thinking.. what if anything can be done in the manual?.. besides tell the user the boat has foam and will not sink?

    I read all the time.. "my boat was about to sink.. or its sinking" or whatever..

    Any ideas guys.. I keep thinking im failing at letting the end user know "THE BOAT WILL NOT SINK"..

    The reason I feel this is important as some can "over react" potentially making a dangerous situation.

    Ideas?

    Grimracer

  11. #11
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    Apr 2007
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    On
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    7,250

    Default

    Whats a manual???

  12. #12
    Join Date
    Jan 2011
    Location
    IN
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    Default

    Grim, Good point. I guess I knew there was foam in there. This is my first fe boat and I did panic a bit thinking I was going to lose my new boat.

    Not sure how you could improve the manual as I don't recall reading that part. An idea though would be to put a "warning" or "info"tag on the esc leads or the rudder. I know that's the only information that I read when I got a traxxas stampede a few years back. Maybe a sticker with basic warning or information on the hatch bottom.

    Thanks

    Hankinator

  13. #13
    Join Date
    Apr 2012
    Location
    Wi
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    13

    Default

    My good friend has the same issue. He called Aquacraft and they told him it's the way the boat is !!! I find this unacceptable and total BS......... They know all about the problem and do nothing............. The MiniMono is a cool little boat but he can't run it with this issue. Even spare parts are not available. He should have bought a ProBoat
    If anyone come up with a good fix, please advise.
    Thanks!!

  14. #14
    Join Date
    Aug 2011
    Location
    Ab
    Posts
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    Default

    I had this issue as well .
    Just go with different grub screws .
    I changed the two that hold the prop wire in place .
    The ones that come with it seem pretty cheesy .
    The ones I put in are great ,I can snug them down with no slipping or stripping .
    I had actually stripped one of the holes a bit in the coupler , what happened was I was trying to tighten the grubs because the shaft was spinning in the coupler .
    The actual problem was that the wire had broken off where the grubs hold it .
    After removing the little piece I installed spare prop shaft , switched to different set screws that were actually a coarser thread than the stock one .
    Cut the new threads with the grub by turning it in and out a few times . HAvent had it come looose once since .
    I also replaced the piano wire in the prop holder part . The stock one came loose , I gor some wire from my LHS and soldered in a new piece .
    Sucker is bullet proof now !
    It has a couple minor issues but I think all rtr's do ?
    Get past that and its a sweet litttle boat .

    Quote Originally Posted by ProBoat59 View Post
    My good friend has the same issue. He called Aquacraft and they told him it's the way the boat is !!! I find this unacceptable and total BS......... They know all about the problem and do nothing............. The MiniMono is a cool little boat but he can't run it with this issue. Even spare parts are not available. He should have bought a ProBoat
    If anyone come up with a good fix, please advise.
    Thanks!!

  15. #15
    Join Date
    Jul 2012
    Location
    FL
    Posts
    480

    Default

    Quote Originally Posted by Crawler Ted View Post
    I had this issue as well .
    Just go with different grub screws .
    I changed the two that hold the prop wire in place .
    The ones that come with it seem pretty cheesy .
    The ones I put in are great ,I can snug them down with no slipping or stripping .
    I had actually stripped one of the holes a bit in the coupler , what happened was I was trying to tighten the grubs because the shaft was spinning in the coupler .
    The actual problem was that the wire had broken off where the grubs hold it .
    After removing the little piece I installed spare prop shaft , switched to different set screws that were actually a coarser thread than the stock one .
    Cut the new threads with the grub by turning it in and out a few times . HAvent had it come looose once since .
    I also replaced the piano wire in the prop holder part . The stock one came loose , I gor some wire from my LHS and soldered in a new piece .
    Sucker is bullet proof now !
    It has a couple minor issues but I think all rtr's do ?
    Get past that and its a sweet litttle boat .
    Can you post the specs of the replacement screws you used and where did you buy them? Thx.

  16. #16
    Join Date
    Aug 2012
    Location
    TX
    Posts
    3

    Default Lost prop shaft blues

    I've lost several propshafts (along with the prop and propnuts thank you).
    I noticed those are all sold seperately.
    The wire either spins loose from between the setscrews and falls out, or the wire pinches off from overtightening the set screws.

    I came up with a simple modification.
    drill an angled hole in the side of the coupler, and bend the shaft wire to run out the side of the coupler.
    This effectively "keys" the shaft. The set screws only have to be tight enough to keep it from pulling out in reverse.

    the coupler has to be removed, and to do THAT, the drive shaft tube has to be shortened.
    Best done with a dremel, being sure to protect the hull with something in case you slip.
    I used wood shim tips.
    then cut back the tube.

    IMG_0597.jpg


    remove the coupler
    use an automatic centerpunch to mark a spot roughly centered between the setscrews.

    IMG_0601.jpg

    start a 1/16" hole straight down into the coupler, just enought to get a bite and then drill the hole through to the center at about a 45 degree angle. Drill TOWARD the propshaft end of the coupler (smaller hole).

    IMG_0608.jpg

    Then drill out the propshaft end of the coupler, increasing the hole size to about 7/32".
    This gives you room to work the wire into the key hole.
    Then it's just re-assembly (don't forget the boot on the end of the propshaft sleeve), and use plenty of shaft grease.
    Final step is bending the propshaft wire.
    A radiused curve as shown will help work the wire into place.
    With practice, a tighter angle bend will help reduce vibration.
    Image is shown out of the boat for clarity and compared to a straight shaft.

    IMG_0612.jpg

    Finished install should look like;

    IMG_0614.jpg

    I hope this saves us ALL a bunch of money!!

  17. #17
    Join Date
    Aug 2012
    Location
    IN
    Posts
    1

    Default

    Hey, that looks like a great solution! Received my Minimono a couple weeks ago, but haven't run it yet since I've felt like I needed some extra drive shafts and nobody has them in stock.

    Thanks!

    Jack

  18. #18
    Join Date
    Aug 2012
    Location
    TX
    Posts
    3

    Default

    Good luck with that!
    I think the rest of us have been buying up the inventory as fast as they could stock it!
    I hope this helps.
    Have fun, its a blast!!
    Advise you start off with the turning rates turned down and about half throttle till you get the feel of it.
    It turns a lot tighter to one side (right I think), and it can flip itself.
    It will float, but you dont want the electronics to get wet.
    I made some course bouys that work great.
    I'll have to post those.

    DC

  19. #19
    Join Date
    Jun 2012
    Location
    WA
    Posts
    58

    Default

    Good idea. Any added virbration noted in the boat? I would think the bent end going thru the coupler would throw the whole thing off balance an possibly add more stress to the motor.

    Hey... no need to cut the tube. Just undo the 3 bolts that hold the motor and cooling plate. But it is a slight PITA to rescrew the bolts.

  20. #20
    Join Date
    Aug 2012
    Location
    TX
    Posts
    3

    Default

    I did try that.
    And you're right! it looks simple.
    I couldn't get a good enough bite on the screws to loosen.

    I expect the amount of weight imballance to be insignificant.
    If anything, the shaft wire in the key hole of the coupler should help to re-ballance.
    I'm actually more worried about the shaft being off centered coming out of the coupler, and reaming out the hole in the end of the shaft sleeve boot.
    I plan to find out about the vibration tomorrow!

    If it explodes in flames I'll let you know!!

  21. #21
    Join Date
    Jun 2012
    Location
    WA
    Posts
    58

    Default

    Wishing you no flames or high temps. :)

    I've been thru 2 shafts and on my 3rd since July. New grub screws and loctite helps but still not problem free. And with all 3 shafts, I notice that they are all misalighnted... really sucks.

    I've asked Jeff http://rcraceboat.com/ if he could make a coupler and wire shaft for the mm but has not replied back.. Anyone know what's the size of the wire? 047?

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