Problems untightening outdrive lower unit's plug

[aJohn79]

I have a 2.3L OMC Cobra from 1990. I want to change the lower unit's oil but I can't untight the plug. I bought a screw driver with the widest flat head I found but nothing. The screw driver slips from the slot. I don't want to damage the slot too much. Are there any tips to untighten a plug?
I bought it used last year so I haven't changed the lower unit's oil yet. It's the only service item remaining on my list.
Thanks!

 

[Haut Medoc]

Re: Problems untightening transom plug

Re: Problems untightening transom plug

You need to buy an impact driver & a mallet......​

 

[aJohn79]

Re: Problems untightening outdrive lower unit's plug

uhmm, is there any other way? I don't want to buy an impact driver just for that. Maybe I'll look to see if I can borrow one.

 

[capthook]

Re: Problems untightening transom plug

Re: Problems untightening transom plug

It should have been one of the first things on your list. But better let then never. I had this same issue with my upper plug. Actually it is called a oil vent screw, and the lower is called the "drain plug". All I did was took a "small hammer" and lightley tapped it a few times then put a lot of grunt into it. It came out. I used a really big flat head as well. Make sure that you replace the seals or you will get water in.

 

[KaGee]

Re: Problems untightening outdrive lower unit's plug

uhmm, is there any other way? I don't want to buy an impact driver just for that. Maybe I'll look to see if I can borrow one.

Harbor Freight Tools...
http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=37530

I don't use mine that often, but when you need it.. you need it!

 

[DukesFin]

Re: Problems untightening outdrive lower unit's plug

Unless the slot is already damaged, the correct size screwdriver (and a decent quality one at that) will do it...

Lots of pressure onto the head of the screw, slow forceful turning...

If that doesn't work, put the blade of a smaller screwdriver on the top of the slot and LIGHTLY tap with a hammer... LIGHTLY TAP to get it loosened.

 

[aJohn79]

Re: Problems untightening outdrive lower unit's plug

Thanks! wow! the impact driver is very cheap at Harbor Freight. For that price I can buy one. Now, it looks like the flat tips are fairly small. Will these work or I need to get something else?

BTW, I already tried tapping the screwdriver but did not help.

 

[marunr]

Re: Problems untightening outdrive lower unit's plug

I had the same problem a few years ago on my 2.3. I used a large screwdriver and clamped a pair of vice grips on the blade, down close to the screw head. Push hard on the screwdriver and turn with the vice grips...it works. (Of course the impact wrench would be better!)

After you get it out, replace it with one of the newer ones that use an allen wrench. They're much easier.