The 9.8A2 and A3 (you didn't say which model -- year is irrelevant) have an exciter, a pulser, and a CD. Any one could be failing hot. The exciter and pulser can be tested with an ohm meter.
FRESHWATER FLUSHING PLUG (40D~140A 2-STROKE & TLDI)
Description
Attaches hose to motor in order to flush motor with freshwater after use in saltwater and/or brackish water.
Fits 40D ~ 140A 2-stroke models and 40-115 TLDI models
Note: picture may not be of actual part
Part #: 3B7600070M...