BC 1unit priming issue

Discussion in 'Research and Development' started by ZARUBA1987, Aug 29, 2020.

  1. ZARUBA1987

    ZARUBA1987 Active Member

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    I’m having a problem with my 1 unit BC pump. It the newer black style compact. So far this thing will not prime consistently. Even fully submerged I removed the brass primer with no luck. Every once in a while it will prime and pumps correctly but so far it’s just not dependable. It not a huge deal given it’s my back up pump for pond side swaps.

    Tips and tricks please
     
  2. Litch42f

    Litch42f Well-Known Member

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    I've had the same issue with brushed motors over 15k rpm or so. At one battle a Captain with this pump had the same issue and did the following field fix:

    Made a notch in the very top of the lower housing effectively moving the priming hole to the top of the housing where the air gets trapped. Ideally you would then solder over the hole in the brass plug.

    20200307_132118.jpg

    It seemed to definitely improve priming. I've played with a cleaner version of this fix but still have not gotten 100% priming on dry starts.
     
  3. ZARUBA1987

    ZARUBA1987 Active Member

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    Appreciate it. I will give it a shot tomorrow. The guys are coming out for a test and tune Sunday before we make the drive to the Labor Day lead fest
     
  4. Bob

    Bob Well-Known Member

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    Are you using a high RPM motor? Something faster than a Stinger?
    This is an issue with the first gen black housing. There’s one one that needs replacement. Ask BC.
     
  5. ZARUBA1987

    ZARUBA1987 Active Member

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    Im running 2s lipos on a RS-550 Mabuchi motor. I believe the motor is 19000 rpm no load. My old school blue BC pump has no issues with same motor.
     
  6. Kevin P.

    Kevin P. Well-Known Member

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    I drill a 1/16 hole through the motor plate. With the 550 motor you'll need two holes to get from the cavity above the impeller to the web area under the motor and then from that cavity to atmosphere. I've lost track of which pump bodies I have (still have some prototypes) but once the boat has enough damage I have not had sinks from vapor lock. Also monitor pump stream and cycle power if it dies off when the boat is damaged.

    Also if its an RS-550 they do better at around 12V, For a 6-7V setup use a stinger, johnson 600 (from BC), or traditional 540, they all pump about the same
     
  7. Litch42f

    Litch42f Well-Known Member

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    I noticed that on the BC website it mentioned something about fixing priming issues in the new pump description. I got my pump probably 8-10months ago and that description was there at purchase. Hopefully I didn’t get left over stock of old housings.
     
  8. ZARUBA1987

    ZARUBA1987 Active Member

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    Kevin,
    Im going to have to pull the pump apart so I can visually reference what your saying. I can see it I just need to put my hand on it for it to make since
     
  9. wdodge0912

    wdodge0912 Well-Known Member

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    I would love to see some pictures of this so I can follow suit. I know I had these issues with my pump when I had it in the Australia, and it is the revised version, but I also had a very slow motor, or I ran an old stinger over voltage and fried it, so I never really got to work the pump out.
     
  10. ZARUBA1987

    ZARUBA1987 Active Member

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    Plans are get breakfast done and get in the shop. Will post pictures of modifications.
     
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  11. Kevin P.

    Kevin P. Well-Known Member

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    Pictures showing two holes
    04B1FAF9-83F8-4112-972B-8104C847123F.jpeg
    silver mark where second hole would go.
    DC10DA0C-D1C6-44F7-B745-4A7A5DC99E39.jpeg
    For a brushless pump I only need one hole since the motor does not cover the entire motor plate. I also use the hole to spray corrosion inhibitor in to the motor lower bearing after each battle

    Basically you need to make a flow path from top of pump housing to outside of the pump
     
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  12. Kotori87

    Kotori87 Well-Known Member

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    just be careful not to make a flow path to the inside of the motor. If you run the motor while the brushes are covered in water they'll wear away much faster.
     
  13. ZARUBA1987

    ZARUBA1987 Active Member

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    FA85A9CF-4370-435C-B2A7-65AD2FB918E9.jpeg 4A205E98-B4C5-4E8D-9570-5CA7A114DC59.jpeg 9644CDF6-C9F3-4175-8AA0-D9757AF5E964.jpeg
    So this is what I ended up doing after trial and error. The mounting bolts and the motor shaft are recessed. This area acts as an air cavity effectively air locking the pump in original form. So with this simple modification the pump has no issues priming. I cut a small vent hole at the top of the lower pump housing in line with the recessed motor mounting bolts. Then from there I cut a valley between both recessed Motor mounting bolts and recessed motor cavity. This ties them all together allowing them to vent though the notch in the top of the lower pump case. Last I removed the most lower plate on the pump I believe it’s supposed to act as a filter. What I found by lowering the pump Inlet it takes less water to prime. Of course I’m still running a screen For debris
     
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  14. JRC123

    JRC123 Member

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    I am not familiar with BC website. What does BC stand for? It is mentioned quite a bit to order parts thru and I would like to see what they have to offer.
    Thanks,
    Johnny
     
  15. darkapollo

    darkapollo Active Member

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    BattlersConnection
    http://battlersconnection.com/
     
  16. JRC123

    JRC123 Member

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