Raw Water Impeller Replacement
The $40 part that protects a $10,000 engine. Don't skip it.
What's Included
- ✓Remove raw water pump cover
- ✓Extract impeller and inspect housing for wear or cracking
- ✓Install new impeller with proper alignment
- ✓Reinstall cover and gasket
- ✓Run engine to verify cooling flow
- ✓Document with service notes
Why It Matters
Impellers fail without warning. The rubber blades degrade invisibly — salt water, sun, heat, and flexing take their toll. Then one day you start the engine and get no water discharge from the exhaust. No raw water cooling means your engine overheats in minutes. Blown impeller = blown engine.
Annual replacement is cheap insurance. San Diego's heat accelerates rubber degradation more than cooler climates. A $40 impeller costs less than an afternoon's work. A seized engine costs everything. The math is simple: replace on schedule, not on emergency.
How Mark Does It
- 1.
Shut off seacock
Close the through-hull valve to stop raw water flow before opening the pump.
- 2.
Remove pump cover
Usually 4 to 6 screws. We keep track of them — nothing gets lost.
- 3.
Extract old impeller and note blade direction
The blades must face the right way. One wrong orientation and cooling fails.
- 4.
Inspect housing for scoring or cracks
If the pump body is damaged, a new impeller won't fix it. We tell you upfront.
- 5.
Install new impeller with light grease
A dab of waterproof grease helps the blades slide in without tearing. Old impellers are the reason for torn new ones.
- 6.
Reinstall cover and new gasket
We use a fresh gasket every time. No reused gaskets — they leak.
- 7.
Start engine and verify water discharge
Look for water flowing from the exhaust outlet. Strong flow = job done right.
Transparent Pricing
$95/hr
Plus impeller kit (typically $35–$60 depending on engine model)
No shop markup. Flat labor rate, every time.
Related Services
Schedule Your Impeller Replacement
Annual impeller replacement is the best engine insurance you'll ever buy. Let's keep your cooling system running.
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