Corroded Exhaust Manifolds & Risers
On inboards and sterndrives, corroded exhaust manifolds and risers cause overheating and can let water into the engine. Here’s what to watch for.
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About This Problem
Saltwater flows through the exhaust manifolds and risers to cool them, and over time they corrode from the inside. Blocked passages cause overheating, and a corroded riser can leak water back into the engine. The damage is often hidden until it’s serious.
Seeing rust on the manifolds or risers? Call Ethan before it turns into water in the engine.
Call 786-351-5363Most Common Causes
These are the causes we find most often.
Internal corrosion
Salt eats the passages and blocks flow.
Failed gaskets
Riser gaskets fail and leak water.
Age
Most need replacement every 4 to 6 years in salt water.
Poor installation
Incorrect installation can let water into the engine.
What We’ve Found on Real Jobs
From Ethan’s job log across South Florida.
Every 4 to 6 years
Exhaust manifolds are recommended to be replaced every 4 to 6 years.
Owner installed
A customer replaced his own exhaust manifolds incorrectly, which cost him a new motor.
Overheat exhaust
Another overheat from exhaust problems. We see a lot of these on MerCruisers.
Factory replacement
Exhaust manifolds replaced with new factory parts.
What You Can Check Before You Call
- Rust or water stains around the manifolds
- Overheating at higher RPM
- Water in the oil or on spark plugs
When to Call
If your manifolds are past 5 years or you see rust and leaks, call before they fail.
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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
How We Fix It
Engine Overheating Repair
Impellers, thermostats, heat exchangers, coolant service, and exhaust manifolds and risers.
Learn moreBoat Engine Overheating
Alarm or rising temp: impellers, thermostats, intakes, heat exchangers, and manifolds.
Learn moreOutboard Not Peeing
Weak or no tell-tale stream: a clogged hose, worn impeller, or blocked intake.
Learn moreGet an Engine Overheating 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
How often should manifolds and risers be replaced?
Every 4 to 6 years in salt water is a good rule.
Can corroded risers damage the engine?
Yes. A leaking riser can let water into the cylinders and destroy the engine.
Do you use factory parts?
Yes, we use factory parts wherever possible.