odd lower unit problem

[Mercs and such]

On my 1984 75hp mercury, my lower unit oil needs to be changed. I have never changed it before. I see the vent screw, and it unscrews. However, the screw at the bottom of the unit is sealed shut and will not budge.

Any suggestions on how to get it out?? i really don't want to have to drill it out.


Thanks, Mercs And such

 

[slasmith1]

Re: odd lower unit problem

Use a manual style impact screwdriver (the kind you hit with a hammer and it spins) it will come right off.

 

[Mercs and such]

Re: odd lower unit problem

Thanks for the reply! where would i find one of those impact drivers? i can't really picture what it is and I'm not sure if they make them but i have no clue?

thanks, Mercs and Such

 

[slasmith1]

Re: odd lower unit problem

this link will show you one example. http://www.thetoolwarehouse.net/p-3064-lisle-29200.aspx

 

[dreamchaser]

Re: odd lower unit problem

Im not sure u want to slam it with an impact driver ,ouch!, may crack , but i would use those flat drivers that come in the impact driver set ,they fit better than ur average flathead screw driver . U can buy them anywhere u buy ur tools , if it still dont budge then maybe a little heat , good luck

 

[slasmith1]

Re: odd lower unit problem

I have been using these for years I was shown this trick by a merc master technician I have never cracked or damaged a drive using this tool. It is the proper tool for the job. do not apply heat to a cast aluminum drive it is a very bad idea.

 

[dreamchaser]

Re: odd lower unit problem

lol to each there own , never want to have a crack in it , i use the drive and a 1.4 inch socket and rachet ,, that works for me

 

[Mercs and such]

Re: odd lower unit problem

thanks everyone for the replies. should figure something out. it gives me some ideas.



Mercs and Such

 

[backyard mechanic]

Re: odd lower unit problem

I've used hammer impact drivers on these LU's for over 30 years. Never once has a LU cracked or even dented. Impact drivers have a large straightblade attachment. Use the largest one available, line it up with tension as instructed then smack the tool. That plug will come loose with one good whack I'll bet. Replace your vent gaskets, oil and then set your vent screws tight with a large hand driver.

If you have a pressure or vacuum checker, it's a good idea to check for leak down before you refill the unit. Usually the SS is the culprit for leak down but it could be the WP O rings, seals or the DS/PS seals. PS seals can be changed out without pulling the unit apart. See the manual for details.