2007 Mercury 25 EFI Gear Oil From Water Intake

MotorlessCSJ16

Seaman Apprentice
Joined
Feb 9, 2009
Messages
47
I just noticed today that I have a little gear oil dripping from the water intake of the lower unit. I've only run it once since it was in the shop and they pulled the lower unit for the water pump. It's not a heavy drip or anything. It's VERY slight and after the last 8 hours hasn't even made it down to the bottom of the skeg.

What could this be? The motor is still under warranty.
 

emckelvy

Commander
Joined
Jan 16, 2004
Messages
2,506
Re: 2007 Mercury 25 EFI Gear Oil From Water Intake

Just to be clear, this is coming from the actual water intakes (on each side of the lower unit) where you'd put flushing muffs on?

Or is it one of the various small holes in the side of the gearcase that are "cavity drains" to prevent pockets of water which could freeze in the winter?

If indeed there is gear oil coming from the intake, the driveshaft oil seals are likely leaking; there's some problem with the pump base (or the sealing of the base); or there's a crack in the gearcase. That's about the only way oil can get back into the intake side of the pump. Most likely is a problem with the oil seals.

Are you sure it's gear oil? It'll smell stinky because of the Extreme-Pressure sulfur additives. If it smells more gassy or oily, it's just unburned hydrocarbons dripping from the exhaust (aka "mung")

Pull the gearcase oil drain plug and check for water contamination. If oil is leaking out of the gearcase, rest assured water will be going in to displace the lost oil.

HTH & let us know what you find out...........ed
 

MotorlessCSJ16

Seaman Apprentice
Joined
Feb 9, 2009
Messages
47
Re: 2007 Mercury 25 EFI Gear Oil From Water Intake

Just to be clear, this is coming from the actual water intakes (on each side of the lower unit) where you'd put flushing muffs on?

Or is it one of the various small holes in the side of the gearcase that are "cavity drains" to prevent pockets of water which could freeze in the winter?

If indeed there is gear oil coming from the intake, the driveshaft oil seals are likely leaking; there's some problem with the pump base (or the sealing of the base); or there's a crack in the gearcase. That's about the only way oil can get back into the intake side of the pump. Most likely is a problem with the oil seals.

Are you sure it's gear oil? It'll smell stinky because of the Extreme-Pressure sulfur additives. If it smells more gassy or oily, it's just unburned hydrocarbons dripping from the exhaust (aka "mung")

Pull the gearcase oil drain plug and check for water contamination. If oil is leaking out of the gearcase, rest assured water will be going in to displace the lost oil.

HTH & let us know what you find out...........ed

Yes, the oil is leaking from where I put the muffs on. I guess I'll check the gear oil in the morning. If it is milky, back to the dealer. Like I said, it's under warranty. The motor has <40 hours on it. In my opinion (although I'm not experienced with this warranty business), there's not reason why it shouldn't be covered under warranty.

Thanks a lot! Keep the opinions/suggestions coming!!
 

trendsetter240

Lieutenant
Joined
Jun 22, 2009
Messages
1,458
Re: 2007 Mercury 25 EFI Gear Oil From Water Intake

This is a 4-stroke right? It could be engine oil leaking down from the powerhead. Much more likely in my opinion than gear oil as your gearcase is below the water intake.

If it's under warranty then by all means, bring it back to the dealer.
 

MotorlessCSJ16

Seaman Apprentice
Joined
Feb 9, 2009
Messages
47
Re: 2007 Mercury 25 EFI Gear Oil From Water Intake

Definitely gear oil as it's a completely different color than the motor oil.

I just checked the gear oil and there is definitely water intrusion. Going back to the dealer on Monday and hoping it's something the warranty will cover. I'm not happy about this...:mad:
 
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