View Full Version : stripped lower unit screw
1fife
11-11-2003, 10:57 AM
bought a used boat and ther screw to change lower unit is out of wack.
looks as if the guy that changed it used wrong size screw driver. Want to change lower unit oil before winter-suggestions?
i can get a screw driver on it and try and turn it, but it to tight for the warn screw
perchjerker
11-11-2003, 10:59 AM
I would try an impact driver.
tbomn
11-11-2003, 11:27 AM
Drill a hole in the center of the plug, then use an "easyout"...done deal.If you don't know what an "easyout" is, check with your local mechanic, he will show you how to use it, and maybe even let you borrow his.
perchjerker
11-11-2003, 01:11 PM
Yes, an easyout will work. But, if you dont know how to use one properly, you can do more harm than good. You need to make sure you drill through the center of the screw, and if you are not careful, the easyout is hardened steel and can break off very easily, leaving you with a hardened piece of steel inside the screw hole.
Thats why I suggested you try an impact driver first.
If the impact driver wont work, my next move would be to get a small, sharp chisel and carefully try to turn the screw in the counterclockwise direction using the chisel and a hammer, trying to "walk" the screw head in the right direction. If it will move a bit, then you can usually get it out the rest of the way normally.
ANGLER203
11-11-2003, 02:00 PM
ANOTHER GOOD WAY IS TO USE A LEFT HANDED
DRILL BIT. THIS WILL USUALLY SPIN IT
OUT.
jigtugger
11-11-2003, 02:05 PM
Not sure if this is really an application for you, but if the screw isn't completely demolished yet here is what I do : Take a relatively cheap flat screwdriver and carefully enlarge the tip by squaring it up on a bench grinder or belt sander until the tip actually fits the width of the screw properly. After you have it set up to fit the screw properly it is much easier to add torque to it without damaging the screw. If needed, you can also add torque on the screwdriver with a small crescent wrench over the blade of the screwdriver just above the screw.
boat nut
11-11-2003, 02:46 PM
How about one of those "screw-out" things that Bob Vila is hawking for Sears? It's supposed to do exactly what is asked of here.
Eye-cather12
11-11-2003, 04:12 PM
Take a flat screw driver and tap it with a hammer in the out direction and then get a new screw from your dealer.
They come out easy.
Seriously, get an impact driver(the type that you hit with a hammer). Set the direction of the driver to loosen the screw, then use your hand to apply a twisting force to the tool to help loosen the screw when you hit it with a hammer. Get a tip that fits the screw well, or make one. If the screwdriver tip slips, use a little dab of valve grinding compound on the screwdriver tip. This really works with any screwdriver that is prone to slipping. I have had a lot of success with this over the years on motorcycle engines and other stubborn applications. Personally, I would avoid drilling and using an easy-out if possible. The magnet in the plug is close to the head of the screw, and it is possible to drill through far enough to push the magnet into the lower unit. Having a stray magnet in the lower unit, or breaking off an easy-out are two risks I would try to avoid. I've done both more than I care to think about, and it ain't fun. By the way, the impact driver can be had for approx $10, so it isn't too bad. Hope this helps.
if it's moderately accessible, get a dremel tool with a cutoff wheel and square up the slot or make it into a phillips head. be careful not to pound too much or crack anything. it's a 50 cent part on a few hundred dollar fragile lower unit.
GLB is right on with the impact driver.
The impact driver does a couple of things:
1. Hitting the impact driver tends to drive the screw driver bit further into the screw, to make better contact.
2. Hitting the impact driver tends to compress the gasket and allow the screw to come out more easily.
3. Insure that the screw driver bit is a perfect of just a tiny bit too big for the slot. Then , when you hit the impact driver the first time, the bit will be driven home for maximum bite on the screw.
Each time that you hit the impact driver, the driver will impart a slight twisting force to the screw.
generally speaking, two or three good hits with the hammer will loosen the screw enough to get it out.
Spend the money and get the driver and save your lower unit.
Take care
REW
Suzuki
11-12-2003, 01:58 PM
I had the same thing and did what Eye-cather-12 suggests. Worked fine. The screw out tool from Sears did not work.
kliph
11-12-2003, 06:54 PM
Did you ever notice how wide the slot is in the drain screw head.
It`s a lot wider than most screwdrivers. I don`t know why.
It just leads to more stripped screws.
I have a big screwdriver with a blade almost as long as the screw slot.
Than with a bench grinder I ground the blade back to just fit in the slot.
No slop in the slot.:) And no more stripped screws.
Good luck.