Bravo X Foaming Issue
 

My Bravo 1 upper failed, so I just replaced it with a Bravo 1X upper remanufactured unit from Jasper Engines.
Prior to installing the X upper (it's mated to an IMCO -2 shorty), I've never seen even a trace of foam in the gear lube monitor, and when the lube warmed up, the level would increase maybe a quarter of an inch max (in the bottle)
I ran the boat over the weekend with the new drive, and now when the lube warms up the level rises almost to the top of the bottle and has about an inch of foam on the surface.
I ran the boat easy at 3500 RPM's max figuring I'd go easy on it to break it in. My guess is that at WOT, the bottle will overflow.
I've read other threads about gear lube foaming, but I can't understand why it didn't foam with the previous Bravo 1, but now does it with the X model. As far as I know the only difference in the two uppers is that the X is stronger (as opposed to the XR which has different cut gears)
The drive runs cool to the touch. I drained the lube as a precaution, immediately after running the boat, and the lube wasn't even warm, so it's not a heat issue (I don't think)
Any thoughts on what could be causing this?

Whose gear lube. I've had Redline foam in one of my X drives, but no correlation to it being an X drive issue. Changed to Amsoil and no problems.

^^^Like^^^ Meaning more than likely the gear oil they put in it.

The shop put Mercury Racing 85-90 in it. I replaced it with Quicksilver High Performance 90 (the dark green stuff), which is what I've always run, just to see if it made any difference. Both lubes foamed the same amount.
The shop is telling me, it's simply air in the drive that needs to work it's way out, but my question was......Why have I never experienced this before??? They don't have an answer.
My concern is, there's something wrong with the reman unit that's eventually going to cause problems.

How are you filling the drive with fluid? From the bottom up?

This is the procedure that works for me:
-Drain drive AND let it drain all of the fluid out of the bottle. (And remove the vent on the upper)
-Hook up garden sprayer modified to fill drive. (other threads on this)
-Fill the drive from the bottom.
-Once you have fluid coming out of the vent hole in the upper, pause, and put the vent plug back in the upper.
-Return to your garden sprayer and keep filling UNTIL you see the fluid JUST start to come up into the bottle.
-Then remove your fill tool, and put the bottom plug in. If timed right, you will have about an inch of drive fluid in the bottle. Let it settle for a bit, and then go back and add more fluid as needed to the bottle to get it to about 3/4 of an inch below the full line.
-Once the boat is in the water, check fluid again.
-Once you run it for about 10 minutes, check fluid again.

You may be trapping air in the system somehow depending on your procedure and setup.

My exact procedure, except, I'm using the tedious hand pump with the stainless fitting on the drive end.
The weird thing is that this is how I did it with the old Bravo 1 Upper and never had even a hint of foam.
IMO the drive is not overheating.........Is there anything else mechanical that would cause this?

Also.......Even if I am somehow trapping air in the system........Eventually the air would work it's way out and the foaming would stop, right?

Is this a serious amount of foam or just some air bubbles in the lube reservoir? I've seen bad reservoir caps cause air bubbles in the lube.

I think your cap needs to be replaced. The cap is a one way valve, it lets air in but not out. If the valve goes bad it will allow the bottle to fill up from expansion of the lube in the drive, next thing happens is air bubbles (foam)

It varies, but running it at 3000-3500 RPM, there's about an inch of foam on top of the lube....Not sure if that's a lot or not. There was never ANY foam with the old upper before, not even when it was failing, so hence my concern.
I haven't run it past 3500 RPM's but noticed the amount of foam is directly proportional to how high the RPM's are.....I'm thinking it will overflow at WOT.
I ordered a new reservoir cap to see if that's the problem. If it is, it would be a heck of a coincidence though, as this started exactly when the upper was replaced.

the o ring in the cap is very important and so is the cap. Try that first to see if your problem goes away. Might want to try a new reservoir bottle as well and they come with a new cap. This the route I would go as it is not that expensive to buy. There is 3 different versions to buy so buy the correct one per your app..

NEXT Possible is the remaner - the rolling torque for putting the upper together was set it up too tight.

post number 11 explains about the reservoir and cap

http://www.offshoreonly.com/forums/d...low-oil-2.html

I'm curious.......Why would the rolling torque being too tight cause foaming? If it's due to the increased heat that would generate, this upper runs stone cold to the touch, as does the lube. I drained it immediately after running it 45 minutes at 3000-3500 RPM and it wasn't even warm.

Replaced the cap.....Problem solved. The reason I was sceptical of it being the cap was because the issue started exactly when the new upper was installed.......Heck of a coincedence.
That's for all the input.

Thanks for all the input.

I have a bravo 1 with the same issue. I'm running Amsoil gear lube and anything over 3000 rpm and it foams up and overflows. Started happening ever since I replaced the gear lube bottle a few years ago. I ordered a new cap so hopefully that fixes it. Tired of my boat smelling like skunky gear lube. I'll report back once I replace the cap. Thanks for the guidance!

Got the new cap installed and ran it hard. No foam! Thanks again for the help.

Man I should do this for a living and charge for it haha

we carry brand new caps and O rings in the tool box for testing purposes as well. It at times is much faster and easier to rule out or rule in by testing simple things like this plus a really fast testing method. The same with brand new IAC s. Another tool for techs to carry in the tool box.

your welcome

your welcome

+2 on the cap had the same problem, replaced the cap and no more mess.