Location of freeze plugs on 3.8 Liter V6 Inboard / OMC sterndrive

[Cauvdog2]

I have a 1982 18' Sea Sprite (United Marine) open bow runabout with a GMC 3.8 liter V6 engine and OMC stern drive. First time winterizing and need to know where the freeze plugs are on the engine block to drain water. Any assistance will be appreciated. Also, any advice on the winterization process will be helpful. Shop wants $475 to do it!

Thanks

 

[Scott Danforth]

you do not drain from the core plugs

there is no such thing as a "freeze plug" they are core plugs to get the casting sand out of the core of the motor during the casting process. no way they will ever protect a motor from freezing.

you drain the motor from the drain plugs. there is one on each side of the motor, just above the oil pan rail, about middle of the block. there are also a drain plug on each exhaust manifold

dont forget to drain the J hose

to winterize:
change the engine oil and filter
fog the engine if you want
drain the 4 drain plugs (petcocks), probing the drains with a stiff wire
add antifreeze with a funnel to the thermostat housing if you want
motor is now winterized
change the gear oil in all 4 gear boxes (intermediate, upper, lower, tilt)
inspect the ball-gears
grease all the lube points
store with the drive down
your drive is now winterized

every 3-4 years, split the drive and change the impeller

if it was up to me, I would pull the drive and store in the basement

 

[Cauvdog2]

Thank you, Scott! I appreciate the advice. I like the happy face in the beer foam. Take care and keep on boating...

 

[Lou C]

If its still the original OMC engine what you'll see are brass fittings screwed into the block and a drain plug with a T shape at the end of it screwed into that. On the older engines that originally came with the large Delco direct drive style starter, they may have a 90* fitting to clear the starter, these can clog easily so use a pick to dig that one out.
Here's a pic, I had replaced the old starter with a smaller PMGR style one by then....