Cleaning The Flame Arrestor - Mercury 350 Scorpion ECT MerCruiser Operation & Maintenance Manual

EFI Propulsion Control Module (PCM): The PCM requires a stable voltage source. During multiple engine operation, an
onboard electrical device may cause a sudden drain of voltage at the engine's battery. The voltage may go below the PCM's
minimum required voltage. Also, the alternator on the other engine may now start charging. This could cause a voltage spike in
the engine's electrical system.
In either case, the PCM could shut off. When the voltage returns to the range that the PCM requires, the PCM will reset itself,
and the engine will operate normally. The PCM shuts off and resets itself so quickly that the engine may only seem to have an
ignition miss.
Batteries: Boats with multi‑engine EFI power packages require each engine be connected to its own battery. This ensures that
the engine's PCM has a stable voltage source.
Battery Switches: Battery switches should always be positioned so each engine is operating off of its own battery. Do not
operate engines with switches in both or all position. In an emergency, another engine's battery can be used to start an engine
with a dead battery.
Battery Isolators: Isolators can be used to charge an auxiliary battery used for powering accessories in the boat. They should
not be used to charge the battery of another engine in the boat unless the type of isolator is specifically designed for this
purpose.
Generators: The generator's battery should be considered another engine's battery.

Cleaning the Flame Arrestor

Fuel is flammable and explosive. Ensure that the key switch is off and the lanyard is positioned so that the engine cannot
start. Do not smoke or allow sources of spark or open flame in the area while servicing. Keep the work area well ventilated
and avoid prolonged exposure to vapors. Always check for leaks before attempting to start the engine, and wipe up any
spilled fuel immediately.
1. Disconnect and remove the crankcase ventilation hose from the fitting on the flame arrestor and valve cover.
2. Remove the flame arrestor.
a - Clamp
b - Flame arrestor
c - PCV hose connection
d - Plenum
3. Clean the flame arrestor with solvent. Dry with compressed air or allow to air dry completely.
4. Clean the crankcase ventilation hose with warm water and a mild detergent. Dry with compressed air or allow to air dry
completely.
5. Inspect the crankcase ventilation hose for cracks or deterioration. Replace if necessary.
6. Install the flame arrestor and flame arrestor bracket. Tighten the flame arrestor clamp to specifications.
90-8M0099729 NOVEMBER 2014
eng
WARNING
!
a
b
c
Section 5 - Maintenance
d
33194
Page 53