What would cause to to overflow under hard running?
Does not happen with casual running, only running hard for a long run, it back flows out the cap.
Was not over full, After awhile when shut down level goes down and shows lower then it was--of course it just pushed some out the cap.

Does not show any signs of water mixed at all. It it did level would be the same or even higher.
Am running a drive shower, and the tube is clean and drive is clean as well--Not like its heating up to the white chalking anyway.

All I can think of its getting hot, and then cooling down.
But could it be the a check valve or something?

Drain the fluid out the prop drain and looks fine.
This is a twin, and the starboard does not do this and maintenance and fluid changes are done the same so I do not think I am missing anything there.

You have a bad cap/O ring,,,,,or it wasnt tight.

Bravos make pressure during use

Swapped caps with other bottle, did it again on the return leg back to shore

Do you have drive showers installed? I know I had the same issue with both of my Bravo-2's on my Amberjack. The drives were getting hot from being on plane for extended periods and the fluid would expand. I installed drive showers and problem was solved.....

Before the drive showers, I tried the new fluid and new caps thing. Neither worked for me.

Make sure that red little check valve is in the top of the cap. Without it the fluid will push out at higher rpm.

You have an air pocket in your drive.

The SURE way to get rid of it is to:
1) Put the boat on a lift or trailer, trim the drive down as far as you can.
2) Remove the reservoir cap.
3) Drain the lube out of the lower gearcase until you empty it.
4) Refill FROM THE LOWER GEARCASE with a lube pump until the reservoir shows proper level.

The NEXT BEST way to get rid of it is to do #1 and #2 from the above list, then:
a) Dump the contents of the reservoir into a container and put the reservoir back on the bracket.
b) Use the same lube pump as mentioned above, and fill FROM THE LOWER GEARCASE with a lube pump until the reservoir shows proper level - during this operation you should get a big BURP of air into the reservoir.

Take note that all of the above procedure is WITH THE DRIVE TRIMMED IN, with the reservoir cap off, and with the lube pump screwed into the drain plug on the lower gearcase.

MC

An the top plug still in the upper unit. As Mcllinstn said. Fill the drive from the bottom till the reservior is full. Allways do this.

Yup, I know, been doing this myself for the last 13 years.
boat is a twin, do the same thing on both every year.
I am positive it is not the way I am servicing it.
Otherwise BOTH would have the same results?

I am going to check out the caps. Maybe just order new ones.

The reason I mentioned that little red rubber check valve in the cap is I had mine fall out one day when I pulled the cap. Didn't think it was that big of a deal so used the cap without it.

Once I started to spin the motor above 5000 rpm it would push fluid out the cap and into the bilge. Bought a new cap for $9 from a dealer and the problem is now gone.

This would be the cheapest fix to try first if your cap is missing the check valve.

That must be the answer to where the drive oil goes in Bravos when not leaked past bottle. The pressure pushes oil out past the prop shaft seals, leaving no signs when trying to find the mysterious leak. All my Bravos always 'used' oil, even when brand new.