Drive oil reservoir

[Burton159]

I just bout my first boat with a stern drive. ( 1996 4.3lx mercruiser). I noticed a reservoir on top of the engine that says drive oil on it. Its about 2" low on fluid. What fluid is this? I've always had outboards. So I changed the lower unit oil hundreds of times. I assumed my inboard would be the same? Is the drive oil reservoir tied into the lower unit or something? Will it drain when I remove the 2 screws on the lower unit?

 

[metsfan3197843]

Yes it’s tied to the lower unit so you can monitor if you are loosing oil or gaining water from a bad seal. It will drain through the normal drive drain

 

[tpenfield]

:welcome: to iBoats . . .

Yes, outdrive oil (i.e. gear oil)

If you follow the tube of the reservoir, you will see it leads to the transom assembly where it is connected to the outdrive. You you loose outdrive oil, the reservoir is there to replace it. It will drain if/when you drain the outdrive gear oil (with the outdrive attached)

When you remove the outdrive there is a ball/check valve at the bell housing that prevents the reservoir from leaking out.

 

[achris]

The oil to use is Quicksilver 'High Performance Gear Lube'... It's the only oil to use in the Alpha drives...

Chris...

 

[Burton159]

[No message]

 

[Burton159]

Is this the gear lube? This is what I use in my outboards.

 

[achris]

Is this the gear lube? This is what I use in my outboards.

That's the stuff. :thumb:

 

[H20Rat]

Is this the gear lube? This is what I use in my outboards.

Outboards can use either the regular or high performance. Alpha is high performance only, so make sure you actually have that type.

 

[Burton159]

That's definitely what I use in my outboards. So on my outboards I pull the 2 plug's on the lower unit so it drains. Then pump new lube in the bottom until it comes out the top hole. So I assume the alpha is the same. But when draining will the reservoir on the engine also drain? When I refill to the point that lube is coming out the top hole, I assume I'll need to put the plug's back in then fill the reservoir? What if high performance was not used? I know it has a blue tinted to it and what ever is in the reservoir is not blue. I'm thinking the previous owner might have used plain 90 weight. I definitely want to get it all out. If the reservoir drains when I pull the 2 lower unit plugs I might dump a quart of high performance in to flush the old stuff out.

 

[achris]

Yes, pulling the plug will drain the reservoir. To refill, from the bottom up, when you see oil coming from the top (vent) hole, put its plug back in and push a bit more oil through (to clear air from the line to the bottle), then top up the reservoir. Be aware there will still be quite a bit of air in the top of the drive, and that will purge out over the next few trips. Just keep topping off the reservoir, but it shouldn't take more than a couple of reservoirs worth.

Chris......

 

[Burton159]

Great, thanks for your help Chris.