first timer for changing lower unit oil, please help

[Thomas P]

i am a little confused, with the motor straight up and down(prop almost on ground) my vent and fill screws are side by side, do i keep the motor in this position, or do i tilt it so the vent screw would be on top and fill on bottom, and is the fill screw also the drain or is that in another location

thanks for your help

almost forgot my motor is 1993 120hp force

 

[Jack Daniels]

Re: first timer for changing lower unit oil, please help

keep your lower unit verticle and the drain plug should be on the other end of the lwoe runit from the prop. You have to get your head in under the boat to see it, its hard to explain but look around underneat the lower unit just where the skeg starts. Youll see it, get a flash light if necessary.

 

[Thomas P]

Re: first timer for changing lower unit oil, please help

on the very bottom back side of the bullet shaped housing there is a phillips head screw, would that be the drain for lower unit

 

[Frank Acampora]

Re: first timer for changing lower unit oil, please help

Thomas: What engine please! It can make a difference.

On most larger Chrysler and Force one piece lower units BEFORE MERCURY changed them, the drain is in front of the skeg. It can be either a pan head 3/8 slotted screw, a 1/8 NPT slotted pipe plug, or a 5/16 allen head set screw.

You keep the engine vertical to both drain and fill. To fill, as oil goes in the fill hole, air is VENTED from the vent hole. After oil comes out the vent hole, you let the engine stand vertical for about 1/2 hour to let any trapped air rise, then you top off the oil until it again runs out the vent. NOW replace both screws.

 

[Thomas P]

Re: first timer for changing lower unit oil, please help

Frank, it is a 1993 120 hp force by mercury marine

 

[Jack Daniels]

Re: first timer for changing lower unit oil, please help

Also pay close attention to the oil, if its milky or has metal shavings you have issues. Milky oil means water in the gear case, which means reseal, and metal means your grinding gears. Also make sure you replace the seals on the vent, fill, and drain plugs, if not done correctly you can get water in the gear box becuase they are in bad shape. Let us know how it goes, and enjoy.

 

[Netjunky]

Re: first timer for changing lower unit oil, please help

Watch this....

http://www.youtube.com/watch?v=Wj0la6c5FDg

Only remove the "Vent Screw" not the screw beside it...never remove that one!!

On the 120hp force engines you fill it from the bottom drain screw until the oil leaks out the top vent screw hole....then replace the vent screw and then the bottom drain screw. The oil is supposed to stay in once you replace the vent screw but some does come out so be ready with the screw.

P.S. That oil is messy!