QD19 Overheat Question – Update

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This topic contains 67 replies, has 15 voices, and was last updated by  retiredoz 2 years, 7 months ago.

Viewing 15 posts - 46 through 60 (of 68 total)

  • beerman57

    Replies: 596
    Topics: 126
    #18980

    I already checked it, hooked up hose to water tube and blocked off the water discharge enough to see water coming down the inside of the mid.


    fleetwin
    US Member - 1 Year
    Replies: 2456
    Topics: 29
    #18986

    At this point, I would go ahead with Mumbles’ drilling advice. Yes, there may be some other issue in that midsection, but the collective knowledge base here can’t come up with it. I personally feel that a midsection with the longer divider between the exhaust and shift cavity would solve the problem as well, but it would have to be from a 58 model only. And, I’m sure you don’t have one "laying around", and if you did, it would probably have the shallow wall as well. Art’s theory about exhaust leaking around the sloppy shift lever makes some sense also, but I don’t know how you could easily "rebush" that shift rod hole.
    So, go ahead and drill into that passage. Worst case scenario: you have to pull the powerhead and seal up the hole with marine tex/epoxy. No big deal. Again, angle the 1/16" hole downward into the shift linkage cavity.


    jeff-register
    US Member - 1 Year
    Replies: 999
    Topics: 40
    #19001

    I believe Garry stated to drill at an angle. Are we looking actively! Seems like a first year (1958) major change with a major mistake.
    I thought it was odd not to have a pencil sized water exit hole from the beginning, but I’m not a Johnson expert by a far reach. I also thought a mid year change as well.

    Mumbles
    Mumbles
    Canada Member - 2 Years
    Replies: 3797
    Topics: 367
    #19012

    Has the temperature of the shift handle ever been checked with an infrared thermometer to verify it is running hot in this area? As we get older, our sensitivity to temperature changes. I’d hold off drilling anything until you’re certain it is too hot.

    If you do drill a hole, there’s two things to consider. First, you are tapping into the motors cooling water supply system so the hole should probably be kept as small as possible to prevent bleeding off too much water and causing the powerhead to run hot. A 1/16" hole would be a good starting point and should be large enough if the pump is in primo condition. You’re not trying to drown the area with water, but just spray it. Second, the angle of the hole comes into play. If it is drilled aimed at the shift linkage, the hot exhaust gases swirling around in there might blow the spray away and down the exhaust opening. You might want to aim it forwards of where you want the water to go. Something like leading a clay pigeon before you powder it.


    beerman57

    Replies: 596
    Topics: 126
    #19013

    Two things, first, I don’t really care about the shift handle being hot, I just mentioned it because it pertains to the midsection being too hot.
    The second thing is, I thought drilling the hole was just for the purpose of cooling the exhaust and thus the mid, with the benefit of the shift linkage getting cooled too. Oh yeah, I pumped the grease fitting on the shift handle full of grease, that should help some.
    I’m going to test the hole I drill before I put the P/H back on. It would be nice if the water sprayed out, but it will probably be more of a stream.


    chris-p
    Canada Member - 1 Year
    Replies: 2428
    Topics: 154
    #19036

    I find the orings are almost ALWAYS dry rotted and cracking if original for the shift handle. I change them on all my motor restorations now.


    pappy
    US Member - 1 Year
    Replies: 616
    Topics: 37
    #19044

    How about just drilling the water tube………………
    The flow will be much faster there and will, therefore, keep the hole clean of debris. Aim it where you want it and at the height you need it. Don’t like where it is? Solder it up and drill another one.
    Some later model engines had holes like this to keep the tuners cool.


    beerman57

    Replies: 596
    Topics: 126
    #19054

    Well, the hole is drilled, incoming water just below the P/H. I tested it, but I wonder how much pressure there will under running conditions. If there is enough pressure it should actually hit the starboard side of the upper mid where it’s getting discolored. How much difference do you think it will make to the exhaust temp in the mid?


    jeff-register
    US Member - 1 Year
    Replies: 999
    Topics: 40
    #19058


    Robert,
    After everything you have been thru with this motor I hope it all works out for you


    fleetwin
    US Member - 1 Year
    Replies: 2456
    Topics: 29
    #19077

    I ran my 58 Sportwin yesterday, it was a hazy day in the 60s so hot ambient temps were not an issue. I’m sure this engine probably has the short exhaust housing divider like yours, but don’t know for sure.
    In any event, the top part of the exhaust housing did heat up quite a bit. Sorry, did not have a heat gun with me. You could only hold you finger on the housing for a few seconds, splashing water outside the housing would produce a little steam. But, my shift handle was not hot at all.
    So, I’m thinking most of what you are experiencing is somewhat "normal" for these engines, and the hot shift handle can be explained by Art’s loose/sloppy shift shaft/exhaust blow by theory.
    Will be interested to hear if the drilled water passage resolves this for you.


    jeff-register
    US Member - 1 Year
    Replies: 999
    Topics: 40
    #19096

    Pappy,
    have you ever drilled out a waterline like this before? I think it’s a great idea. All of my Mercury motors have a tiny hole drilled in the waterline pipe but it was I.D.ed as a drain for the powerhead after it was turned off.
    Robert, I think Pappy has a great idea. Best I have read so far!!
    Jeff

    Mumbles
    Mumbles
    Canada Member - 2 Years
    Replies: 3797
    Topics: 367
    #19098

    The copper tube in this motor is only about 6" long and runs from the pump to a grommet in the lower part of the housing. The rest of the water tube up to the powerhead is a cavity cast into the exhaust housing so drilling a hole in the copper tube wouldn’t have any bearing on cooling the upper part of the exhaust housing. It would have to be drilled in the cavity where previously indicated to help cool the upper casting.


    pappy
    US Member - 1 Year
    Replies: 616
    Topics: 37
    #19099

    Oh well……….just a thought.


    beerman57

    Replies: 596
    Topics: 126
    #19105

    I want to thank everyone again for helping with this.
    Fleetwin, I bet the water up there is a LOT colder than the mid 80 degree water down here. Maybe this is normal for this model, but how many QD19’s has anyone ever seen with a discolored midsection? My ’62’ ten hp has the same short divider, should I drill a hole in it too?
    I’ll let you know how the QD does, probably Monday or Tuesday.


    handyandy
    US Member - 1 Year
    Replies: 24
    Topics: 5
    #19197

    Just an FYI- the bulletins listed on FiberGlassics are not viewable, I just put a list there for reference. I have a bunch scanned from the 1960’s to early 1970’s and am waiting for the AOMCI Library to expand.

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