MERCURY COIL 398-173

Function and technical context

The Mercury 398-173 ignition coil is a critical component of the ignition system that generates the voltage necessary to produce the spark at the engine spark plugs. This piece works integrated into the ignition circuit, receiving low voltage impulses and transforming them into high voltage to guarantee the correct ignition of the air-fuel mixture in each cylinder. Poor coil operation causes combustion failures, progressive loss of power, difficulty starting and erratic engine behavior in navigation conditions, especially in demanding waters where extreme reliability is required.

When to replace this part?

Common symptoms of coil failure include loss of revs under load, intermittent failures in acceleration, difficulty in cold starting and a noticeable increase in fuel consumption. Although there is no fixed replacement time interval, it is advisable to inspect the condition of the coil at each seasonal inspection, especially after intensive or prolonged use in a saline environment. Preventatively replacing the coil when early symptoms are detected prevents unexpected strandings at sea and much more costly emergency repairs.

Equivalent manufacturer part numbers