Milky Lower Unit Oil
Gear oil that looks milky or like coffee with cream means water is getting into your lower unit. Here’s what to do before it destroys the gears.
Ethan, the owner and mechanic, answers the phone · Open 7 days a week
- Same / next day availability
- On-site & marina service
About This Problem
Milky gear oil means water is mixing with the oil, almost always past a worn seal. Caught early, a reseal is a fraction of the cost of a new lower unit.
Gear oil came out milky? Call Ethan before you run it again.
Call 786-351-5363Most Common Causes
These are the causes we find most often.
Prop shaft seals
The most common leak point, often damaged by fishing line wrapped around the shaft.
Drive shaft and shift shaft seals
Upper seals wear and let water in.
Drain and vent screw gaskets
A missing or worn gasket lets water in.
Damaged shaft
A bent or pitted shaft tears new seals.
What We’ve Found on Real Jobs
From Ethan’s job log across South Florida.
Zero oil inside
An aftermarket lower unit on a Yamaha 250 failed with zero oil inside.
Resealed lower units
Resealed lower units and new prop shafts on Mercury, Suzuki, and Yamaha outboards.
Lower unit plus trim leak
A lower unit was resealed along with a full service and a trim leak repair.
What You Can Check Before You Call
- Drain a little oil from the bottom screw
- Look for fishing line around the prop shaft
- Check the oil at every 100 hour service
When to Call
Stop running the motor and call. Running with water in the gear oil damages bearings and gears quickly.
No call center. No front desk.
When You Call, the Owner Picks Up
Every call goes straight to Ethan, the owner of EG Marine Services and the mechanic who does the work. There’s no receptionist taking a message and no waiting on a callback from someone who’s never seen your boat.
Tell him what’s going on: the alarm on the display, the noise at idle, the engine that won’t turn over. Ethan knows Yamaha, Suzuki, Mercury, and the rest of what runs in South Florida inside and out, so you’ll usually get a straight answer on the first call, whether that’s something you can check yourself or a visit to your dock.
- Straight answers, not a script
- Diagnostic questions answered on the phone
- Honest advice, even when the fix is simple
- The person you talk to is the one who shows up
Ethan
Marine mechanic
Describe what the boat is doing and get a real answer from the mechanic, not a message taker.
Call Ethan: 786-351-5363Open 7 days a week
Get an Outboard Lower Unit Repair Scheduled
Call Ethan directly786-351-5363Open 7 days a week · No call center or front desk, you talk to the person doing the work
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Frequently Asked Questions
Can I keep running with milky gear oil?
No. Water causes rust and gear failure. Have it pressure tested and resealed.
How much does a lower unit reseal cost?
Far less than a new lower unit. Call with your engine model for a quote.
What causes water in the lower unit?
Usually worn seals or fishing line cutting the prop shaft seal.