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85HP Force Lower Unit Drain Plug

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  • 85HP Force Lower Unit Drain Plug

    Not being familiar with any outboard but Mercury/Evinrude, I began looking for the lower unit drain plug on my recenly acquired Force 85. With a bit of help, I found it. Problem: Allen wrench wiped the corners of the allen screw drain plug. I drilled through it, with the idea of using an "Easy Out" for removing the rest of the screw, but it will not budge (I've leaned on it heavily). Any suggestions? My thought is to continue drilling out the allen screw until (1) it's all gone and I still have some good thread left; or (2) I drill and tap to the next larger size. Wondering what others might think of this situation. Thanks for any help you may provide. Gary

  • #2
    Re: 85HP Force Lower Unit Drain Plug

    I once had that motor and had the same issue, you have 2 options drill the hole out to he next size that will remove the remants of the existing plug and tap it ( when tapping the new threads, coat the tap with grease, this will some what kept the shavings , some what from filling the lower unit, althought I'd rinse the lower unit with diesel ot kersoeine )or get a used lower unit $$$$$, I did the first option and ran that motor till I sold it , the benefit of having a larger hole is the oil drains some what faster, just take your time in retaping the hole, and use a brass or stainless steel plug


    • #3
      Re: 85HP Force Lower Unit Drain Plug

      My 87 125hp has the same issue. Dang drain plug is in so tight I cant's shift it with either metric or imperial allen keys - and I didn't want to round it out - so I did things the hard way - removed lower unit took out fill and vent plugs, up-ended it and drained out of the fill/vent holes. What a pain.....


      • #4
        Re: 85HP Force Lower Unit Drain Plug

        i'm having same problem...i quit trying to take it out and just topped off the oil ...i could prob get it out but it will be ruined...are these plugs for sale anywhere?
        Run it till the prop falls off!!!


        • #5
          Re: 85HP Force Lower Unit Drain Plug

          That just means you are puttingh the plug in way to tight. A 1/4 turn past hand tight should be fine. 3 years now. When I cange my oil there is never any water in it to my surprise and delight.BTW I hate that little plug. They used a big screw on the shift pin why not on the drain?


          • #6
            Re: 85HP Force Lower Unit Drain Plug

            Don't know for sure...(can't remember really)...but aren't those plugs a tapered plug thread? If you use a little dab of gasket sealing compound on the threads, that'll help keep the threads from seizing. Biggest problem with them I think is the fact that there's two different metals in contact....aluminum and I beleive the plugs are a stainless alloy.
            When in doubt...use the manual

            Rayland, Ohio....Along the Muddy Banks of the Mighty Ohio River.


            • #7
              Re: 85HP Force Lower Unit Drain Plug

              Hi all, I have the same problem with drain plug ,I drained lower unit by removing propellor and anode ,when these are removed you will see four bolts around the prop shaft remove the lower two being careful not to lose the two small o rings ,when oil stopped coming out I added a couple of ounces of fresh oil to give it a flush till clear oil flowed ,put it back together and re filled as normal. Not ideal solution but it gets the job done. Hope this helps someone. Jim B
              no point having an umbrella if your shoes are leaking.


              • #8
                Re: 85HP Force Lower Unit Drain Plug

                Well, since you already drilled it, Try hammering in an old Torx bit that you don't want. Then heat the case--aluminum expands way more than stainless. Actually, heat the case and whack the plug hard to try to break corrosion before hammering in the Torx. And since corrosion is the culprit, coat the next plug with teflon pipe tape or silver anti-seize. Remove it every season to prevent corrosion from getting a hold on it.

                If you do decide to completely drill out the setscrew--yes, it is a 5/16 allen head set screw and must be bottomed tight to seal-- then you have the choice of re-tapping 1/16 NPT, 1/8 NPT or 3/8-16 like the fill and vent plugs. NPT plugs are tapered as are the tapped holes. Do not tap too deep or the plugs will not seal. Do it in stages and try the plug in between.

                NPT taps in these sizes are available at Fastenal, Graingers etc. They are not available in these sizes at Sears etc.


                • #9
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                  Re: 85HP Force Lower Unit Drain Plug

                  I just wondered where you found a new plug. I removed mine but I am afraid to put it back in. I visited local shop, and local hardware, no one has stainless steel. Thank you for your help!