The most common reason for a high water level in the muffler is excessive cranking of the engine without the engine starting. When the engine is running, it produces exhaust pressure which maintains the water level at the design level. If the engine is cranked too long and fails to start, salt water will fill the muffler and back-flow into the engine (since the water pump runs while cranking). This can be disastrous to your engine requiring a major engine overhaul to repair.

• Body of drain valve is a 1/4"-18 NPT fitting
• Actual fitting diameter (measured at base of threads) of body is 1/2"
• Body of fitting requires a 5/8" wrench