Changing Lower Unit Oil on a 91 Force 120

[Magik-12]

I'm planning on doing this.. but am unsure how much lower unit oil I will need?<br /><br />Also, is quicksiler lower unit oil acceptable?<br /><br />I've read enough horror stories to make sure I dont pull the shift pin, anything else I need to worry about?<br /><br />Just take out the drain plug at the bottom, and the vent & fill plugs at the top? Drain/refill?<br /><br />Can it be that simple?<br /><br />-John

 

[The Marine Doctor]

Re: Changing Lower Unit Oil on a 91 Force 120

Yes it is that simple. Quicksilver or Mercury brand gearoil is the factory recommended oil.<br /><br />TMD

 

[Magik-12]

Re: Changing Lower Unit Oil on a 91 Force 120

Cool.. thanks TMD.<br /><br />How much oil should I be picking up? 4 qts?\<br /><br />-John

 

[The Marine Doctor]

Re: Changing Lower Unit Oil on a 91 Force 120

It is generally cheaper to buy in bulk..so yes that would be the way to go.<br /><br />TMD

 

[JamesGY]

Re: Changing Lower Unit Oil on a 91 Force 120

I used less than a quart to fill my 120 up. But, if you want to save $$, listen to TMD.

 

[Old120]

Re: Changing Lower Unit Oil on a 91 Force 120

I have a 92, 120 and I use merc. oil. It seems to work fine. Is it true the seals in the three sloted plugs are one-time-only seals. Meaning, they compress the first time you use them and do not seal proper after that<br />tks

 

[The Marine Doctor]

Re: Changing Lower Unit Oil on a 91 Force 120

If you are using the carbon fiber seals..just once is all you can use them for.<br /><br />The plastic ones are a little more tolerant..but should be replaced none the less.<br /><br />So in either case...use once and dispose.<br /><br />TMD