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Author Topic:   Removing Drain Screws for Lower Unit Oil
Born Free posted 03-25-2003 11:29 AM ET (US)   Profile for Born Free  
Does anyone have any suggestions on how to loosen the two drain screws which allow you to change the oil on the lower unit? I have a 1990 Johnson 60HP VRO Engine. I've tried unscrewing the stainless steels plugs with a flat head screwdriver but they won't budge. Should I spray them with WD-40? Any suggestions will be helpful.
Whalerdan posted 03-25-2003 12:00 PM ET (US)     Profile for Whalerdan  Send Email to Whalerdan     
Man, I was just doing this yesterday and was going to post the same question. I was thinking heat, but don't want to damage seals. I think and easy out would just snap off, besides, drilling into that SS would be tough. Didn't think about the WD-40, but I think I'll try that if we don't get any better answers.
newt posted 03-25-2003 12:24 PM ET (US)     Profile for newt  Send Email to newt     
If the screwdriver can get a good bite, you can always use a pair of vice grips clamped onto the screwdriver to get more leverage. Use the largest driver that will fit in the slot, push the screw driver in as hard as you can and have a partner bang on the vice grips with a hammer.

I have also used a manual impact driver on stubborn screws. I might be calling the tool by the wrong name, but basically you hit the thing with a hammer and it twists the screw bit. The advantage is that as the bit twists it is also forced tight against the screw which helps avoid stripping the slot out.

mtbadfish posted 03-25-2003 12:44 PM ET (US)     Profile for mtbadfish  Send Email to mtbadfish     
You could try a large square shaft screwdriver and a Crescent wrench. One of you holding the screwdriver, the other turning it with the Crescent wrench.

Same basic thing as Newt's, just different tools.

whalersman posted 03-25-2003 12:45 PM ET (US)     Profile for whalersman  Send Email to whalersman     
I have had good luck using a Large Screwdriver with a square shank.. I then put an adjustable wrench on the square shank and turn. This gets quite a bit more torque then the vise grips would on a round shanked screwdriver.

This has worked for me many times..

whalersman posted 03-25-2003 12:46 PM ET (US)     Profile for whalersman  Send Email to whalersman     

You beat me to the screw..... :-)

Bigshot posted 03-25-2003 01:21 PM ET (US)     Profile for Bigshot  Send Email to Bigshot     
I have a square shanked Craftsman and a 5/16 fits well. You do not need a lot of leverage, just more than turning the handle. Wrapping the driver with a hammer helps. Try using the screwdriver on the corner of the screw head and tapping it with the hammer to budge the screw(like you would on an 8" access deck plate), it will come out.
Born Free posted 03-25-2003 01:25 PM ET (US)     Profile for Born Free    
Well those were some quick responses and I appreciate the feedback. It seems I'm not the only one with the same problem. Unfortunately, I'm not sure when I will have the extra set of hands to help me solve the problem. I've used one of those impact screwdrivers before and while their handy, I'm looking for a cheap fix to the problem.
kglinz posted 03-25-2003 01:48 PM ET (US)     Profile for kglinz  Send Email to kglinz     
Here's the tool newt mentioned. It will work. Sorry about the long URL, Jim.
[Removed extremely long URI which led only to an error page announcing "Session has expired", a typical result in these long URI's which are based on tracking the visit to the website.]
Whalerdan posted 03-26-2003 09:16 AM ET (US)     Profile for Whalerdan  Send Email to Whalerdan     
I thought about the impact wrench. Does anyone worry about cracking the casing using one of these? I know we use to use them on motorcycle casing screws and never had a problem, so maybe I'm just worrying too much.
lewain posted 03-26-2003 11:56 AM ET (US)     Profile for lewain  Send Email to lewain     
Guys its just opening a stubborn jar it just needs a little tap. Position the screw driver turned to rest on left side of screw slot and gently tap with a hammer you will be suprised at how easy it will loosen up.
whalernut posted 03-26-2003 04:55 PM ET (US)     Profile for whalernut  Send Email to whalernut     
Are the screws just tight and stubborn, or are they Saltwater fused? I don`t fish in Saltwater, but I have seen what Saltwater does to lower units on Outboards-UGH!! Jack.
jimh posted 03-26-2003 10:49 PM ET (US)     Profile for jimh  Send Email to jimh     
[Administrative post]
Baseline posted 03-27-2003 04:47 PM ET (US)     Profile for Baseline  Send Email to Baseline     
Hey guy's - There is a tool that you can order from its called a Drag Link. It is a socket with a big flat blade that fits perfectly into the drain plugs on both the lower unit and Trim and Tilt. I think the correct size is 15/16. The Drag Link fits both 3/8 rachets plus 3/8 impact driver the kind that you hit with a hammer. The drag links are about $8.00 each. I bought a set of four 9/16 through 1-3/16" for $19.99, the link is below. Or Search for "Drag Link" and they will come up and you can choose your size and see the picture to get a better idea of what I'm talking about. I have not found these in the stores, but you could try..

My motor was used in saltwater for 10 years, I could not break the drain plugs free, I tried everything in my tool box. I ended up buying both the drag link and an impact driver. I also used PB Blaster, sold at most better autoparts stores, under $6 a can, great stuff. The impact driver is really useful, you hit it with a hammer and it turns the drag link. So there is little chance of it slipping out of the slot. Impact drivers range from $8 to $40 buck, might want to check sears also.

Also, once you get the plugs out put a little anti-sieze compond on the thread, so that you will not have to use the impact drive every time.

Good luck..

[Go to and search for "drag link". These instructions are shorter than the URI which was provided here, again with session information so that it was likely to expire and turn into a useless but extraordinarily long string of characters. Have I mentioned that long URIs are not appreciated?--jimh]

JBCornwell posted 03-27-2003 06:17 PM ET (US)     Profile for JBCornwell  Send Email to JBCornwell     
I vote for the impact wrench/screwdriver.

Be sure that the blade fits the slot in the plug very snug. Tap a few times. It doesn't usually require a heavy blow, but if that can't get them loose, none of the other suggested solutions will work either.

Red sky at night. . .

Born Free posted 03-28-2003 03:13 PM ET (US)     Profile for Born Free    
Thanks again for all the suggestions.

Last night I tried the hammer technique with the screwdiver head on the left side of the screw and it worked perfectly with the exception of a couple of scrapes to my lower unit.

If my engine were brand new and I wanted to avoid the scrapes/gouges and dings I probably would have invested in the impact driver. As it is, the housing on my lower unit looks beat up so the scrapes/gouges and dings don't bother me.

Bigshot posted 03-28-2003 03:18 PM ET (US)     Profile for Bigshot  Send Email to Bigshot     
$6 can of Tempo engine paint and she will look "brand spankin"!
jimh posted 03-28-2003 09:54 PM ET (US)     Profile for jimh  Send Email to jimh     
[Removed another ridiculously long URI]
jimh posted 03-28-2003 11:44 PM ET (US)     Profile for jimh  Send Email to jimh     
I don't quite understand the physics of this, but it seems to me that when removing a difficult screw, it is often much easier if the screwdriver has a long shaft.

Does this make any sense under the current laws of Physics?

simonmeridew posted 03-29-2003 06:43 AM ET (US)     Profile for simonmeridew  Send Email to simonmeridew     
I'm not sure either about the physics here, but there may be several issues: the longer the shaft, the easier it is to keep the screwdriver perpendicular to the screw and thus bottomed out/even with both sides of the slot. Thus you get even torque on both sides and less tendency to "cam out". Part of the trouble with a Phillips screw driver is the design includes four inclined planes which almost guarantee "camming out" with any kind of major force. Secondly, a longer shaft may have some elasticity, i.e., it rotate on itself a small amount allowing for a steady more gentle twisting force. Less sure about this second reason, but some things which came to mind.
Yearly maintenence on the lower unit lube will make the screws more likely to come out when you want them to. On a frozen up screw my vote would be for one of those impact drivers. I think most are mainland Chinese and not esthetically pleasing but work. Sometimes you give a potentially stubborn screw one whack tightening and it will loosen easier.
One last administrative thing. I'm not paranoid but...I never did understand the difference between 'that' and 'which' as used several lines above where I wrote, "...but some things which came to mind." I had other things on my mind in 8th grade when we covered this stuff. 50:50 chance I got it right. (At least I got the quotation marks right.)
Just kidding.
Dr T posted 03-29-2003 12:55 PM ET (US)     Profile for Dr T  Send Email to Dr T     
Jimh and Simon,

Just a small point of elaboration: The long screwdriver may act as a torsion bar. When you put torque on the handle (on the end away from the screw) when applied to a frozen screw, you are acting to store energy in the bar. When you reach a critical point (when the screw begins to rotate), the energy will be released as the torsion unwinds. The amount of twist is miniscule, but I think it may contribute.


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