Blow Out Plug, White Plastic | CAMCO-36103

Camco Blow Out Plug | Part #36103 | White Plastic | Schrader Valve | Marine Plumbing Winterization

Before you pump antifreeze through your boat's freshwater plumbing, you want to blow out as much standing water as possible first — water left in the lines dilutes your antifreeze and reduces its freeze protection. The Camco #36103 blow out plug threads into your boat's city water inlet or plumbing access port and connects to a standard air compressor via its built-in Schrader valve, letting you push compressed air through the lines to clear standing water before winterizing. White plastic construction, hand-tightens without tools, and small enough to keep in your dock box or winter prep kit year-round.

Part Details:

• Part Number: 36103
• Manufacturer: Camco
• Type: Blow Out Plug
• Material: White plastic — rust-proof
• Connection: Schrader valve — compatible with standard air compressor fittings
• Installation: Hand-tighten, no tools required
• Use: Clearing standing water from marine freshwater plumbing lines prior to antifreeze winterization
• Condition: New

Additional Information

Why Blow Out Lines Before Adding Antifreeze:

Antifreeze winterization works by displacing water in your plumbing lines with a freeze-resistant solution. The more water that remains in the lines before you add antifreeze, the more it dilutes the antifreeze — reducing its effective freeze protection temperature. On a line rated for -50°F protection, significant water dilution can raise that threshold to -20°F or higher, leaving your system vulnerable in a hard freeze.

Blowing out the lines with compressed air first removes the bulk of the standing water before antifreeze is pumped through, ensuring your antifreeze maintains its rated protection level throughout the entire plumbing run. This is especially important for longer line runs, horizontal pipe sections where water pools, and any line with a low point that doesn't drain by gravity.

How to Use the Camco 36103 Blow Out Plug:

1. Shut off the water supply and open all faucets and valves in the system to release pressure
2. Thread the Camco 36103 into your boat's city water inlet or plumbing blow-out port by hand until snug
3. Connect your air compressor to the Schrader valve fitting on the plug
4. Apply compressed air at low pressure (30–50 PSI maximum for most marine plumbing) and open each faucet, fixture, or valve one at a time to blow water through and out
5. Once water flow stops and only air exits, close that fixture and move to the next
6. After all lines are blown out, pump antifreeze through the system for full freeze protection

Frequently Asked Questions

1. What pressure should I use when blowing out marine plumbing lines?
Most marine freshwater plumbing systems are rated for 30–50 PSI maximum working pressure. Use compressed air at the lower end of that range — 30–40 PSI is typically sufficient to clear standing water from plumbing lines without risking damage to fittings, valves, or flexible hose. Never exceed the pressure rating of the weakest component in your plumbing system.

2. Does this plug fit my boat's city water inlet?
The Camco 36103 is designed to fit standard city water inlet fittings commonly found on boats with pressurized freshwater systems. If your boat has a non-standard fitting or blow-out port, verify the thread size before ordering. Contact us at MacombMarineParts.com if you need help confirming fitment for your specific installation.

3. Do I still need antifreeze after blowing out the lines?
Yes — compressed air blow-out removes the majority of standing water but cannot guarantee every fitting, low point, and valve body is completely dry. Antifreeze winterization after blow-out provides the insurance layer that protects any residual water from freezing. For complete protection in cold climates, always follow compressed air blow-out with antifreeze treatment.

4. Can I use this plug for my marine head or raw water systems?
The blow out plug is designed for pressurized freshwater plumbing inlets. Marine head systems and raw water cooling circuits have different winterization procedures — consult your vessel's service manual for the correct approach for those systems.