Fuel problems don't just stop engines; they explode boats. Gasoline vapors are heavier than air and settle in the bilge, waiting for a spark. Diesel is safer but feeds the biological sludge that kills engines offshore.
1. The Tank Inspection
Most tanks are buried. You can't see the bottom. So how do you survey them?
The Mirror Trick
Use an inspection mirror and a flashlight to look at the underside of the tank if there is any gap. Aluminum tanks corrode from the bottom up where they sit on wet neoprene or wood.
The "Smell Test"
Open the bilge hatch. Use your nose before your eyes. A strong smell of raw gas is an immediate "Stop Survey." Do not turn on any switches. Evacuate.
2. Hoses: The 10-Year Rule
Fuel hoses have a finite life. They rot from the inside out.
- Markings: Look for "USCG Type A1" (fire resistant, low permeation). If it says "SAE J30" (automotive), it is wrong.
- Age: Hoses are dated. If they are over 10 years old, recommend replacement, even if they look shiny. Ethanol fuel eats older rubber.
- Double Clamps: Fill pipes (1.5 inch) need double hose clamps.
3. The Grounding Wire
As fuel rushes through the fill pipe, it creates static electricity using friction. A spark at the deck fill can ignite the fumes.
The Check: Measure resistance (Ohms) between the metal deck fill and the tank top. It should be near zero. If it's open, the ground wire is broken.
4. Filtration
Racor filters are standard. Look at the bowl.
- Clear Bowl: Allowable for Outboards and Diesel.
- Metal Bowl: REQUIRED for Inboard Gasoline engines (regulations require fire resistance). A plastic bowl on an inboard gas engine is a federal violation.
Conclusion
Fuel system leaks are non-negotiable. There is no such thing as a "small leak." Any fuel fluid or strong vapor presence is a Safety Item.