Lower Unit

[twag]

How do you change the lower unit gear case lube without loosing half the lube on a 25HP Merc?<br /><br />Merc says to insert tube at bottom drain opening and squeeze tube until it runs out at the top opening. <br /><br />Trouble is I'm working against gravity and most of spills.Is there a easier way?

 

[achris]

Re: Lower Unit

Put the top (vent) plug in before you remove the tube from the bottom hole.<br /><br />Chris...........

 

[KCLOST]

Re: Lower Unit

twag, maybe you are not using the quart size gear lube container... Most, if not all have a tapered cap that allows it to be inserted into the hole and it makes a great seal....<br /><br />Chris also has good advice on the vent cap...

 

[bamadave]

Re: Lower Unit

twag, in your post, how do you CHANGE the lube? Pull the top vent plug, pull the lower drain plug, let ALL the lube drain. It should be a nice dark color without looking milky. If it does look milky, LU has a leak. It it looks good, proceed. THhe coolest thing out there to replace the lube is a pump. The pump is foe lube in a quart bottle like oil comes in. Screw to filler tube in the lower drain hole, pump lube in until lube comes out vent tube, replace vent plug, with a new gasket for the plug, this creates a vacuum so the lube won't run out the drain, remove fill tube and replace the drain plug, again using a NEW gasket for the drain plug. I was taught not to reuse gaskets. Not spending .50 can cost you 500.00. Use a hand impact to tighten these plugs to keep them from coming out when cruing on the water.

 

[twag]

Re: Lower Unit

Thanks everyone. I went to my local West Marine and discovered the gear lube pump. Why doesn't Merc suggest using this tool in the owners manual? It certainly makes life easier. <br /><br />I was wondering about replacing the gaskets on the plugs as well..Thanks bamadave

 

[andrewkafp]

Re: Lower Unit

You will find that you don't need the pump. Due to the viscosity of the oil, you have ample time to put ya finga over the hole and also, the manual suggests that you should let a bit drip out anyway. Are you using 90 grade marine gear oil ?<br />I have had absolutely no problems changing oil or topping up on my 1980 Merc manually, just make sure you use new washers each time.