Aerated overflow oil
 

#4 drives are rebuilt last year, no issues last year, magnets look good, Only thing I did was replace the oil this year and now the oil in overflow bottle gets aerated after a run.
The other drive no issues.
I pumped oil from the bottom till it came out the top ...maybe some air bubbles?

Maybe your drives are overheating & " releasing/bubbling" from looking at your avatar? She seems to increase my operating temp...

Just a few bubbles or is it turning to foam? I've seen this before where it just puts a bit of bubbles in the oil and after a few outings it subsides. If you are getting a pretty good froth in the bottle that would be a bit concerning.

I agree , its frothy, last time it did that the drive took a dump shortly.
Even after a short 15 minute ride that drive had some signs of heat .

Same oil or different oil ?

If different, maybe the oil you are using now doesn't have the correct , or correct amount, of anitfoaming agents in it. Basically, not made for your app.

Other than that or an air pocket, I 'got nothing' for you. LOL.

Thanx SB :D ... the other drive is just fine.
I`ll keep an eye on it

agree,Other than that or an air pocket, I 'got nothing' for you.thanks http://goo.gl/qsgfyi

Make sure your gear lube bottle has the O-ring underneath the cap. Also it could the cap and o-ring. Try swapping them to see if problem stays or follows.

Also some extra info for anyone. Many times we see this issue as the gear lube rises in the bottle and aerates is from when the drive has been worked on internally. The rolling torque specs were set up too tight.

I have the expansion bottles in the picture. I did not realize it but the caps on the drives were air IN only. Meaning there was a baffle to allow air in but not out.. I removed that baffle so they could 'breathe'. Thats the only change since last year when all was fine.
How does the cap and O ring affect the oil?


http://33outlaw.zenfolio.com/img/s12...92005260-3.jpg

I believe you want the one way valve in there with the o-ring sealing on the cap. This keeps the drive slightly pressurized when warm keeping the foaming down, and letting air into the system as the oil cools and contracts. Of course you know that the oil will foam if there is any water in it at all. This is going to sound silly; I trim the drive all the way in, jack up the front of the boat and pump oil in the bottom of the drive, I get about another 1/2 quart of oil into the drive. You can see the bubbles in the overflow bottle as the oil is pumped. This is on a wet #6 that holds 18 1/2 quarts. No foaming since I started doing this.

Sorry I had no idea of your set up only you know it best. It is always hard to second guess up here what people really have. Anyways the cap on the gear lube monitor from mercruiser plastic bottle / stock app is persay a one way valve as it lets air in at the brownish / red rubber underside and the nipple just sticking out.

It is somewhat hard to put into words to understand fully - the cap and the o-ring (underside of the cap) hold the pressure in the drive system. As the drive is running it builds internal pressure, the one way valving in the cap allows air to enter into the drive reservoir to equalize those pressures, with out the o-ring or the cap or the vent clogged in the cap for proper sealing pressure, the gear oil will rise / bubble out the gear lube reservoir as it builds its internally pressure. Hope this makes sense.

Post 10 is correct you need to put it back in - I promise this is your problem like I tried to explain in my first post but not really knowing what you had for reservoirs. It was basically along those same exact lines.

I have speedmaster 4's also on my boat. Except I don't have boxes and use the original inner transom plate with reservoir/expansion chamber. Whats weird is, when I Bought my boat, it had been sitting for a couple years. I went to drain the drive oil, and when I loosened the lower drain plug, oil squirted out as is was under pressure. Ran it for that season. Changed oil again, and same thing, loosen plug, oil shot out at me.

I then noticed on the inner transom plate, there was a NPT pipe plug, where the little vent plug should be, like the vent on top of a borg warner. I looked up on mercruiser parts, and saw they listed the vent to go in that hole, so I ordered the vents and installed them. I no longer get oil spraying at me when loosening the plug. But, now you have me thinking, did something know something about plugging that vent, in order to keep pressure in the drive, so that it helps keep water out or something? I was worried it was building too much pressure and maybe blowing a seal out or something.

Hmmm. See I thought it was an expansion bottle to allow for expansion but I see I was wrong.:frog:
Im` pretty sure I threw the parts for the check valve away.. dammit.

Dan I wonder if that's why the acrylic in the reservoirs was cracking. It doesn't take much pressure to do that in a tank like that. I had those tanks on my formula with trs. The acrylic cracked on those too. Removed them and used the stock trs reservoir and no issues

yeah ok.. thats why all of mine were cracked

Too much pressure can cause seal leaks. In the case of the cracked bottles IMO you are building too much pressure. Internal heat can cause too much pressure build up. Maybe check your drive for bearing wear or any form of wear. Also like I said drives that have been set up with too high rolling torque specs can do this as well.

It does allow for expansion. There is air on top of the oil in the drive, when the drive oil and air get warm, they expand a bit. Just the heat of the day will put a bit of pressure in the drive if the night before was fairly cool. The drive should not get real hot with use though, shows up as way too much expansion/foaming.
A bit of pressure in the drive helps keep water out also.

Both drives are fresh with lots of new parts. Colabella rebuilt them last summer. The cracks are just a crappy brittle acrylic. Everything was fine last year.

Not SSM's, but a buddy of mine has been having some air bubbles in the gear lube reservoir of one of his Bravo I drives. I told him to switch caps this weekend and see if the problem moved with the cap. It did.

After changing the caps to work as designed (hold pressure ) the problem is still there on the one drive.. I was really hoping it was going to be that simple.
oh well

Update
 

Got rid of the obviously crappy gear oil I bought one here and put in some Amsoil severe gear and no more aerated oil in the resevoir entire weekend :daz:

This oil was supposed to be the $hit.. its not its crap..do not buy.

http://33outlaw.zenfolio.com/img/s5/...64924609-3.jpg


One problem down.
Now the other side is always low and I see my extension box is full of gear oil.. loose or busted hose somewhere.. one step forward two steps back ..STANDARD!