Drying out your Tohatsu M50D
  • Next time you put your Tohatsu under water and have to DRY it out, here is something you need to know big time.  The bottom bearing area in the crankcase can hold water for a long long time.  Even after you have run the engine, while supplying it with cooling water, for 30 minutes or more the water will still be there. AND.. if this is the last time you run it for the season, you could have real problems come springtime.

    Possibly, If you race the engine in the next heat or two that weekend or the next weekend, you may get rid of the water that way.  I can't answer that one.

    To explain a little more:   The area where the oil injection did mount is now blocked off by a metal plate about an inch and a half long, held in place with 2 bolts (10mm hex) on the lower right side of the crankcase aft of the split-line.  With the pump and quill-shaft gone, there is a void that will hold water.  Also, the lower cylinder intake bypass passage is low enough to hold water.  And, the lower crank bearing will hold water.  Running the crapo out of the engine statically doesn't seem to suck the water out.  Bouncing around the race course might.

    What I recommend:   Remove the "block-off" plate to drain off excess water.  You might also tilt the engine forward and to one side to drain the intake bypass and bearing area.  You will be impressed with all the water that still comes out after you thought you had run the engine long enough.

     If this was the last race for the season... I would recommend splitting the crankcase.   If it's not the last race, and you're just trying to get things running to make the next heat...go ahead and race it, but pull the plate at the end of the day to check for water.

    As many you know, both my motors went into the lake last September.  Back here at the shop I ran them both for at least 45 minutes on the hose. Then I fogged the heck out of them, and put them away for the winter.    Well, this February when I decided to re-ring both motors, guess what?   There was at least a 1/4 cup of brownish water down there that drained out when I pulled the block off plates off.  BOTH motors.

    The block off plate has a gasket which is usually re-usable..... usually.   I keep them in stock ($3.00).  Questions?? Call me.

    Alex
    207-737-4570 


    APBA Member #: 11195
    Boat #: 8A
    Classes: D hydro FE hydro 20 SShydro
    Region 1
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  • Are you going to the nat'l mtg Jan 2018 ?    If you are, stop by and chat.  If things go as planned (they always do as you know) we will have a booth with a couple engines on display you can play with.


    APBA Member #: 11195
    Boat #: 8A
    Classes: D hydro FE hydro 20 SShydro
    Region 1