Stuck Oil Drain Plug...

Discussion in 'Outboard Maintenance' started by HaMm3r, Mar 28, 2012.

  1. HaMm3r

    HaMm3r Well-Known Member

    Anyone have any tips on breaking free a stuck lower unit drain screw on a 25hp Merc? Never had one this stubborn before and I don't have many more attempts before the head will require grinding to give the screwdriver an edge to bite into again. :-/
  2. actionc

    actionc I Love!

    go to harbor freight and get an impact driver .

  3. swaddict

    swaddict Thread Killer

    Have you tried gently tapping the screw with an old screwdriver and hammer, sometimes that will help loosen the screw
  4. HaMm3r

    HaMm3r Well-Known Member

    Thanks for the replies guys. Tonight, I'm going to lay the motor down flat on the ground, so I can put a little more force on it and try your suggestions. Thanks!
  5. cutrunner

    cutrunner Cert. Yamaha technician

  6. Brett

    Brett > PRO STAFF <

    I've had to assist with a few abused older outboards. Not mine!   :eek:

    I've found a few that it appeared as if the drainscrews had never been touched, since new.
    I've had to modify very large screw drivers, using a grinder and file, to modify the blade
    to obtain an exact fit to the drainscrew slot, so the blade wouldn't slip. Then using an adjustable
    wrench on the flats of the screwdriver shaft, just above the flare of the blade,
    was able to pop the threads loose. Be careful, you don't want to shear the screw off.
  7. HaMm3r

    HaMm3r Well-Known Member

    Got it! Tried the impact driver and it barely budged (but it did move it slightly). Soaked it in penetrating oil and attempted the modified flathead screwdriver and vice grips...nothing. Ground the tip of an old chisel flat and used it to tap each side of the screw in a counterclockwise direction with a hammer...voila! It came free! :cool:

    Thanks for the advice guys. :)
  8. noeettica

    noeettica Well-Known Member

    Glad you got it ! I have VW tools that I used on relief plunger screws 1/2" drive ... fork great on the foot drains ...
  9. jladdsmith

    jladdsmith I Love!

    Glad to hear that you made it work. An impact driver plus penetrating oil does wonders in these type situations.