Oil drain plug over-tightened

[Hook 'em Horns]

I want to drain the oil in the lower unit of my 1989 150 HP Evinrude, but the previous owner must have over-tightened the lower drain plug and the flat-head screw slot is rounded out too...ugh! What are my options in removing this plug and is this part easily replaced? Thanks so much! This forum is awesome!

 

[Vic.S]

Re: Oil drain plug over-tightened

If there is any usable slot in the head of the plug, a big screwdriver that really fits the slot and that is squarely ground with absolutely no rounding off of the edges or corners (as new in other words) and which will accept a small spanner on the shaft.

Start with a sharp tap, that might loosen the grip on the screw a bit . It often helps to slightly tighten a screw before undoing it as well.

Support the engine firmly lying on its side, put all your weight on the screwdriver and try to turn the screw sharply with the spanner on the driver.

Heat might help, a kettle full of boiling water over the gearcase first will expand the alloy of the case away from the steel screw.

A freezer spray, the stuff plumbers use to freeze pipes, directed at the screw head is another trick to try.

If that does not work or the screw head really is too far gone to attempt that maybe an "easy out" will do the trick but drilling the pilot hole in the screw really needs the engine clamped down firmly on a drilling machine, and a broken off "easy out" will double the trouble.

 

[JB]

Re: Oil drain plug over-tightened

Howdy, Hook-em.

An impact screw driver is probably your best bet. Use the largest slot-tip that you can get into the slot. It was probably installed without the gasket or with a crushed gasket. That usually causes overtightening.

You will need new gaskets for the drain/fill and vent plugs anyway, so pick up a new plug or two while you are out there.

 

[Hook 'em Horns]

Re: Oil drain plug over-tightened

Thanks so much for the prompt responses. I really appreciate it. I'll give these suggestions a try. I'm afraid however that there is so little groove left on the plug that no matter the srewdriver, I may not get enough of a bite to loosen it. Any chance I could drill another hole in the plug (small enough it doesn't damage the existing threads) and force (gently hammer) maybe a philips screwdriver or smaller flathead into that hole and loosen it that way? Many thanks again for the great advice.

Hook 'em

 

[Basher]

Re: Oil drain plug over-tightened

Hook

If you are going to drill a hole you might as well get your self a screw extractor (easy out). You are going to have a hell of a time trying to "hammer" a screw driver into a hardened steel screw. However, when you drill the hole you are going to cause metal shavings to enter the gear case housing so flush it out prior to refilling with oil.

Basher

 

[Reggie08]

Re: Oil drain plug over-tightened

I've used the hammer method before on an old Mercury motor I had. The motor had been sitting and the drain plug was seized in pretty good. I actually used the pointed end of a large flathead screwdriver and with it at an angle, on the outside edge of the drain plug, it broke free after I tapped it a few times.

 

[kenmyfam]

Re: Oil drain plug over-tightened

Impact driver or educate it with a centre punch and hammer, get the centre punch mark fairly deep and to the outer edge of the screw then tap firmly at a 45 degree angle in a counter clockwise direction.
If you need a further explanation let me know. This method has brought many a broken bolt out of a thread as long as you can get enough access to it. Should be easier on a screw head.

 

[Benny1963]

Re: Oil drain plug over-tightened

hammer type impact as fr said ,with the largest bit you can get in screw
done it more than once or you can tack a small bolt to it if ya have welding setup mig ,
i dont use eaze outs on anything unless its last option
but also have nevr tried on drain plug the last one i did cleaned and slightly
deepend with dremel and used hammer impact .

 

[Hook 'em Horns]

Re: Oil drain plug over-tightened

Thanks to all of you that took the time to respond to my dilema. I'll let you know which method does the trick. Thanks again!

Hook 'em

 

[kenmyfam]

Re: Oil drain plug over-tightened

Good Luck !!!!

 

[iwombat]

Re: Oil drain plug over-tightened

Stay away from the ez-outs on anything stainless. Do a search in the forum for broken ez-out if you don't believe me.

 

[jonesg]

Re: Oil drain plug over-tightened

carbide disk in a dremel will cut the screw slot a bit deeper, then an impact driver will pound it loose ,

I watch a tech hit the screwriver a couple of times before even trying to remove those screws, and they weren't stripped or stuck, he just does it as a matter of course, full weight on the screwdriver with one arm/shoulder and a wrench on the screwdriver shaft, they always come loose with a crack.!

 

[JT!]

Re: Oil drain plug over-tightened

if you own a hammer and a cold chisel, try etching a new line.

if you can at least take a nibble out of the edge of the screw, a small punch-pin can be used to turn the screw by tapping on an angle, at the edge of the screw.

 

[dimock44]

Re: Oil drain plug over-tightened

B

Stay away from the ez-outs on anything stainless. Do a search in the forum for broken ez-out if you don't believe me.

Been There Done That.Took me a week of fussing with the broken EZ Out. I agree with impact driver method