Using Gear Lube

2004 Mercruiser 5.0 MPI Engine SN: OM648883

Bravo I Drive SN: OM170345

Purchased this boat last summer. Never had to add any gear lube all summer. Took the boat in last fall to a dealer for service. Part of the service was checking/testing the drive and changing the gear lube. Have had to add almost a quart of gear lube to the reservoir so far this summer. Is this normal after having serviced?

Re: Using Gear Lube

A quart seems very excessive. They would've had to screw up bad if it was them. Was that all at once? What period? Reservoir dry or lowering some every day?

Re: Using Gear Lube

A quart is a huge amount.
Do you see a leak anywhere? The drive should be 100% oil free.

It is filled by pumping the Lube in the bottom drain plug, from the bottom up.
If an inexperienced worker filled it from the top, like on a car, that might explain it.

My Alpha drive will use 2-3 ounces in the first 10 running hours after a lube change.
Once the few air bubbles rise to the top , it will not use any more.

Re: Using Gear Lube

I had a similar issue but with my Alpha 1. It slowly started using larger and larger amounts of lube. At first I had hoped it was from the prior year's winterization and air bubbles as mentioned above but it became apparent that wasn't the case. Maybe a quart and a half in a whole summer. I ended up having to pay for the 200 hour tune up at 100 hours of engine time. That tune up included changing the impeller and the seal that was allowing it to leak into the water so you never saw any sign of lube anywhere.

Re: Using Gear Lube

Gives credance to doing a pressure test after drive maintenance!

Re: Using Gear Lube

I ran the boat in the driveway before hauling to the lake and had to add approximately 1/2 quart after doing that and have had to add approximately another 1/2 quart after 2 hours of use this summer. The reservoir had never been dry. There are not any visible leaks and the invoice states they pressure tested the drive.

Re: Using Gear Lube

Sounds like air to me. Especially if you don't have a bunch of smelly gear oil in your driveway.

Re: Using Gear Lube

find a new mechanic as sounds as if it was done incorrectly as stated above especially if it loses no further oil.

Re: Using Gear Lube

So if it stops "using" gear lube, it was air and was serviced incorrectly? Seems like a lot of air to me.

Re: Using Gear Lube

baileyjd1 said:

So if it stops "using" gear lube, it was air and was serviced incorrectly? Seems like a lot of air to me.

Click to expand...

Yes it is!
The lower unit (The Prop Housing) uses more than a Quart. (Alpha Drive)
The upper unit (The Bevel Gears) uses about a Pint. (Your Bravo Drive uses even More!)
The two units are connected by a single small (<1/4") passage about 2 feet long.

In a correct filling, the lower unit is filled to capacity from the bottom,
until it overflowed up the passage to fill the upper unit.

If the Upper unit was top filled like a car by an inexperienced worker,
The lower unit would initially have NO LUBE in it.
As the air in the lower unit warmed and cooled it would expand and contract;
The air would "Burp" up the oil passage and eventually fill the lower unit.
This would leave the Upper unit with NO LUBE in it until you filled it up again.

In a correct, Bottom-Up filling, there is a small amount of air initially trapped in the lower unit that "Burps" its way out over the first few running hours. This normally amounts to just a few ounces.