1956 Scott Atwater 7.5 hp Bail-a-matic impeller

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  • Buccaneer
    Buccaneer

    US Member - 1 Year
    Replies: 4268
    Topics: 758
    #227649

    Attention Mumbles!
    I got the Honda impeller for the retrofit
    in the subject motor, so I started playing around while awaiting
    O-rings for the pump. The original impeller key (at least what
    came out of mine) was a round pin, 1/2 long, about 1/8″ diameter,
    which I’m told is too loose for the Honda impeller.

    I found a piece of 1/8″ square key stock and it fit nicely
    in the impeller keyway after filing two sides down about .005.
    It seems like it will work good. The impeller still has a little
    movement “radially” on the driveshaft, as the original design.
    Any reason not to use the square key vs. the original round one?

    I’m not going to make the bailer pump useable on this motor.
    Perhaps I will on the other one that’s in better shape.
    I was planning on installing an aluminum “puck” in the bailer cavity
    like Mumbles did.
    It appears that the puck in the photo is a snug fit and stationary,
    and has plenty of room in the center for the driveshaft.
    Just wondering if Mumbles has any advice on said puck design,
    anything you’d do different, etc., or anyone else that’s done
    the same engineering.
    Thanks!

    DSCN0181

    DSCN0184

    Bailer-Pump-Blank-cartridge-installed-1

    DSCN0179

    Prepare to be boarded!

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    Mumbles
    Mumbles

    Canada Member - 2 Years
    Replies: 4652
    Topics: 260
    #227661

    I’ve seen chatter on other forums to about having to do a bit of filing to get the Honda impeller to work on these motors but I thought they were referring more to the slot in the impeller itself. They might have been referring to motors which have a hole drilled thru the shaft and the pin sticks out a bit on each side requiring another slot in the impeller. Heck, I’ve pulled motors apart before which had a piece of rusty nail driving the impeller and it worked. Stainless would be ideal but Mercury got away for years using steel keys which rusted away. I don’t see any reason why your setup wouldn’t work and I might have to do it myself when I get around to working on my bailer again.

    As for the puck I made, it was a drop in fit and I used some epoxy to hold it in place and seal it around the bottom. I don’t know if I’ll be able to get it out again when the time comes to get the bailer function working again. As for the center hole, it could have been bored smaller but I was in a bind, way behind, and too lazy to change out to the four jaw chuck to get the correct offset.

    Buccaneer
    Buccaneer

    US Member - 1 Year
    Replies: 4268
    Topics: 758
    #227668

    Mumbles, thanks for your reply and info. I dug thru my box of aluminum and found a short piece of
    round stock just a hair bigger OD than I needed. It already had a 5/8″ hole bored in the center.
    I don’t have a 4 jaw chuck anyway, so offsetting wasn’t a great option.
    Of course, the hole in the pump housing and puck don’t line up 100%, it appears that the
    driveshaft will still have clearance.
    None of my stock O-rings will fit the pump housings, so hoping the ones I ordered will work…..
    if they ever show up. Worse comes to worse, I’ll try some o-ring spaghetti seal and super glue.

    DSCN0185

    DSCN0186

    Prepare to be boarded!

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    Mumbles
    Mumbles

    Canada Member - 2 Years
    Replies: 4652
    Topics: 260
    #227740

    I’ve been thinking about something else I did to my bailer pump when it was apart and I’m sure i tapped at least one, maybe two, inlet/outlet holes in it for plugs to prevent any chance of water leaks or exhaust gases getting into the cooling system. I’m sure the bailer inlet was one and possibly another one somewhere. Or, it might have just been a thought I had before coming up with the puck idea. Not sure.

    Buccaneer
    Buccaneer

    US Member - 1 Year
    Replies: 4268
    Topics: 758
    #227746

    I’ve been thinking about something else I did to my bailer pump when it was apart and I’m sure i tapped at least one, maybe two, inlet/outlet holes in it for plugs to prevent any chance of water leaks or exhaust gases getting into the cooling system. I’m sure the bailer inlet was one and possibly another one somewhere. Or, it might have just been a thought I had before coming up with the puck idea. Not sure.

    I was thinking about sealing the bailer holes with silicone,
    but if my little brass 1/8″ pipe plugs would work, I might
    do that.
    If my o-rings for the pump and bearing for the lower unit
    ever show up, I might get the lower unit back together
    soon. Anxious to stick the lower unit in a bucket of water
    and spin it over via a drill to see how the Honda impeller
    performs.

    Prepare to be boarded!

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