Any Ideas How to Get a Stubborn lower unit screw out:1990 15Hp

[OptsyEagle]

So I am trying to change the lower unit oil in my 15Hp 1990 Evinrude and the slotted screw for the bottom of the LU is not unscrewing. I had it out this time last year. I have tried a regular slotted screwdriver, a larger tire iron with a slotted end, one of those easy outs drivers that turn counterclockwise as you whack the other end of it. Pentrating oil, although I imagine the washer is probably preventing that from doing much and a heat gun. So far it does not want to budge. Any ideas for this would be appreciated.

 

[jimmbo]

An Impact Screw Driver, however finding a Slotted Head large might be a challenge

 

[Fun Times]

Have you tried a combination of fair amount of heat and an impact screwdriver right there after?

If possible, a good flame tends to work better than a heat gun.
impact screwdriver

 

[tphoyt]

If you have a dermal you could cut a new a slot across the existing and start fresh.

 

[OptsyEagle]

So I want to thank you all for your ideas and suggestions. Although it was probably one of the most stubborn screws I have ever had to unscrew, my efforts were finally met, this morning, with success.

After many attempts of whacking it, heating it, cooling it, and different forms of slotted screwdrivers, all ending in failure, today I used a fairly small slotted screwdriver, with an end only about 1/8" wide, positioned on one outer edge of the slot in the LU screw and whacked it very hard and it finally turned.

I actually did this a few times yesterday, without success but the difference today was that yesterday I used a mallot as my hammer and today I used a regular steel hammer. I figure this not only provided the power but also a better transfer of vibration. Secondly, as for the power. Yesterday I spent significant effort to ensure no damage came to my aluminum lower unit, while I was whacking this small slotted screwdriver, whereas today I added significant anger, some really filthly profanity, resulting in a much higher force to my whack, and that seem to make the vital difference. lol

Anyway thanks again. You guys are great.

 

[saltchuckmatt]

So I want to thank you all for your ideas and suggestions. Although it was probably one of the most stubborn screws I have ever had to unscrew, my efforts were finally met, this morning, with success.

After many attempts of whacking it, heating it, cooling it, and different forms of slotted screwdrivers, all ending in failure, today I used a fairly small slotted screwdriver, with an end only about 1/8" wide, positioned on one outer edge of the slot in the LU screw and whacked it very hard and it finally turned.

I actually did this a few times yesterday, without success but the difference today was that yesterday I used a mallot as my hammer and today I used a regular steel hammer. I figure this not only provided the power but also a better transfer of vibration. Secondly, as for the power. Yesterday I spent significant effort to ensure no damage came to my aluminum lower unit, while I was whacking this small slotted screwdriver, whereas today I added significant anger, some really filthly profanity, resulting in a much higher force to my whack, and that seem to make the vital difference. lol

Anyway thanks again. You guys are great.

Yeah, many success's getting postal on things....of coarse it gone the other way to....either way no more problems!

 

[99yam40]

Find an impact screwdriver that you hit with a hammer, they are good tools to have around

 

[Crosbyman]

reinstall new nylon washers !! and having had the same kind of fun to take out a stripped HEX head bolt on my 75hp I now wrap those oil screws with a a few layers of yellow teflon.

 

[Chris1956]

Find an impact screwdriver that you hit with a hammer, they are good tools to have around

Gee, I have been using a hand impact driver to tighten and loosen gearcase screws since the 70's. I never had a screw loosen up and fall out, nor have I had one that would not come out.