Stripped Oil Drain Screw Lower Unit-1968 Evinrude 18 HP

goalie147

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Jul 5, 2017
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I have been working on fixing the seals on the lower unit of an 1968 18 HP evinrude and managed to strip the upper drain screw, What have others done to fix this? Can you tap new threads just a little bigger into the housing? Thoughts Ideas?

Thanks,
 

boobie

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Nov 5, 2009
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Yes, helicoil works good. You may have to cut it off to the right length though.
 

F_R

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Jul 7, 2006
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Curious, how did you manage to strip that thing? Or is that something you would rather not say.

Yes, Heli-Coil
 

goalie147

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Jul 5, 2017
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I bought a new screw and was done replacing the seals so making sure it wasn't going to leak through the screw and made it extra tight but that back fired. How would you recommend I cut one of those inserts to the right length?
 

cfauvel

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Aug 16, 2005
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never used one, but don't you have to break off the piece that crosses the cross section(the piece that is used to drive the coil into the boogered threads ), then you are left with a piece of metal in the wrong place?
 

just_james

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Nov 9, 2016
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never used one, but don't you have to break off the piece that crosses the cross section(the piece that is used to drive the coil into the boogered threads ), then you are left with a piece of metal in the wrong place?

You are correct plus there will be metal shaving from drilling and tapping
 

boobie

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You put grease on the drill and the tap to catch the metal shavings. The piece you break off from the helicoil used to install it you do with a needle nose pliers.
 

clemsonfor

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Sep 19, 2005
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Most if not all the shavings should be pulled to the outside. Use the grease like mentioned on the tap and keep it wiped clean when it gets a lot.

Also get like a quart or two of diesel and flush out the gear case before you fill it back up with oil.
 

cfauvel

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Aug 16, 2005
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Boobie and ClemsonFor...
thanks, great suggestions if ever I have to use a helicoil with no access to the cavity.

Hope OP follows suggestions.
 
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