Gear lube drain screw won't break loose.

AFFTAXI

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Sep 4, 2017
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Hi everyone. I have a 1997 Force 85hp engine and I am having the hardest time trying to break loose the small allen head screw to change lower unit gear lube. The last thing I want to do is strip it out. Has anyone ran into this problem before and how did you end up getting yours out? Thank you for any suggestions.
 

savetexomabeaches

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Jul 4, 2013
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I can never understand why they put an allen in there. PB blaster, lime away.. just make sure you have the allen wrench fully seated in before turning.. tap it in with a hammer if needed
 
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Jiggz

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Oct 23, 2009
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For last resort, you might just have to leave it alone and just use a suction hose to empty it.
 

pete j

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Nov 21, 2012
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I did what Jiggz said if I didnt I would have just stripped out the allen head with no chance of ever getting it out. I tried many different ways but it was not going to move.
 

kbh121956

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Jun 30, 2013
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I used PB Blaster with the correct size of an allen socket on both of mine. It was a bad design for sure, they like to let water seep in. I used liquid Teflon on it to stop the seepage. It comes out much better now.
 

jerryjerry05

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In extreme cases I use a small propane torch.
They loosen right up.
Heat the aluminum around the screw.

Even with Teflon tape they still weep a bit of water.
 

fishrdan

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Jan 25, 2008
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No experience with your drain plug, but when my Mercruiser's plug is too tight for my liking, I grab the impact driver and give the plug a couple of taps, comes right out...
 

jerryjerry05

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The impact driver would strip the head of the set screw used in the drain.

​The plug is a TINY!!! allen headed set screw, not the screw with the slot used in most applications. very poor design!
​The torch has never let me down even on the Mercury/OMC/Yam drain plugs.
 

funk6294

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Apr 26, 2009
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Give it a few light taps with a hammer. That usually will help break the threads loose. Then try backing it out.
 

jerryjerry05

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funk, it's a set screw.
​Any taps with a hammer will smoosh the soft aluminum and spread it and lock it in place.
 

funk6294

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Apr 26, 2009
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I get that's its a set screw. There are two ways to do it. Use an allen socket and tap on that, or use a drift/punch. You not looking to kill it, just a few light taps is all it usually take to jar the corrosion from the threads.
 

AFFTAXI

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Sep 4, 2017
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I just snapped off a screw extractor in it, and it still won't come loose. I will probably have to drill it out and re-tap it and put in a larger, fine threaded, screw?
 

kbh121956

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AFFTAXI, if I'm not mistaken you can remove the prop and behind that remove the bottom lowest screw to drain the foot. Just remember to remove the vent screw. You can also fill the foot by use one of the two screws towards the top of the outdrive. just remember to remove both of them when refilling. I wouldn't mess with trying to drill out the drain plug. They like to allow a small amount of water to seep into the drive anyways. When filling the foot, allow extra time for the lube to settle and work out any air voids.
 

AFFTAXI

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Sep 4, 2017
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I did basically replace the gear lube by filling thru one vent hole on top until it ran semi-clear from the other one. I say "semi-clear" because it started out as a chocolate milkshake! I am trying to get as much of the old lube out as possible so I can see if I have a Shift Seal leak. It looks like the Prop Shaft seal is brand new, so I don't know if the last guy could not get the drain plug out and left bad lube in, or what? But if I can drain it by removing a seal holder bolt, I assume that is the bolt you are talking about, I will try that first.
 

QBhoy

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Mar 10, 2016
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Glad you got it sorted, presumably...last resort after all above advice given, might have been to insert the Allen key or socket into the screw head...then get a centre punch and punch at least 2 of the sides of the hex. This would squash in the metal and ensure the Allen key had an unreleasable grip on it.
Old marine engineering trick !
All the best.
 

jerryjerry05

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Chocolate?
​Sounds like there is more problems than the drain???

Take the lower unit off.
Mix water and soap in an old spray bottle.
Drain the oil as best as you can.
Do a pressure test, spraying the seal points with the soapy water.

Sometimes it won't leak and you need to turn the shafts and activate the shift shaft.
Even then it might not leak??
That could be the leak is going in, vacuum leak.
​The only way thing to do then is reseal the whole drive.

​Draining the oil using the lowest bearing cage bolt: You can do that but it's best to change the seal if you do.
 

kbh121956

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Jun 30, 2013
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When JerryJerry05 states to do a pressure test. he is saying to use a very small amount of air in the lower unit. 1 or 2 pounds of air otherwise you can damage the seals. I would do as he said as he knows the Chrysler/Force outboards way better then I do. Please keep us updated on how it turns out.
 

jerryjerry05

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The normal pressure test is about 10-13#
1-2 might not show a leak.

​If it's sealed right?? it can actually hold up to 20# +
 
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