bravo 3 leaking gear oil at props

Moondoggy

New Member
May 22, 2010
81
Peoria, AZ
Boat Info
230 BR Signature
Engines
7.4l Mercruiser Bravo3
got the boat out of storage and lowered the drive. when i did this gear oil came out between the 1st prop and the housing. what happened in storage? i had no leaks last season and the gear oil was changed before storing.
 
Just a thought but when the oil was changed did some run down the drive and puddle in that area then when you lowered the drive it just ran out. Is it a constant leak or did it stop?
 
If you have a B3 prop wrench, I would pull the propellers and have a look. Could be a leaking prop shaft seal. I would check it out before your next outing.
 
would bet you have had a small seep for awhile and didnt show up while you were using because water kept it washed off.

pull props and check for fish line wrapped up around prop shaft. if possible clean shaft and raise back up and hope for the best. with the props off you can get a better idea of where the oil is coming from.

the oil drain is below the props and while anything is possible, i don't see a likely way for oil to be spilled where would run out of props with no trace of it running in first.
 
If there was a leak, wouldn't it create milky oil? If so, you would hope the mechanic would have noticed and red-flagged it. From an optimistic viewpoint, I'll vote for Tbirdvet's diagnosis!
 
pulled both props this am seals seem to be good no fishing line or other debris were in there. exhaust port still had gear oil in it...the leak did stop only a few ounces came out.gear oil level is right at the full line on resevoir tank. no gear oil or any fluids in bilge.hate to dump brand new fluid but i just may have to. im hoping for the best...i need to get my hands on a pressure tester to be 100% sure..sigh:huh:
 
i wouldn't dump or change oil, till your sure it came out of the drive.

i think you can pressure test through the top level hole if you plug the hose to the reservoir.
 
There are o-rings between the lower unit and the upper part of the drive. If they are leaking the oil runs down through the exhaust port and out the props. Makes you think the prop shaft seals are leaking. I had oil running out but no water intrusion. Simple fix.
 
well i drained the gear oil it was clean and had no water in it. i seperated the upper and lower and replaced the orings. reassembled and then did a pressure check held 15psi no leaks. so i will reinstall it on the boat and fill it with gear oil again. :huh: still dont know where the fluid came from :wow:
 
I have a 99 310 Sundancer with Bravo 3' duo props. I keep losing oil in my starboard drive but only when I'm moving. It's not leaking into the bilge and the the reservoir is not milky. Any ideas ?
 
Oil going out usually indicates problem w/prop shaft seals. Water coming in and mixing w/gear oil (usually a full reservoir) usually means a loose washer on lube fill points (most probable), crack in lower unit, or a bad seal on the upper drive side.
 
Just realized thread start day of 2011... eh.
 

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