A healthy spark plug, which is indicative of a healthy marine motor, comes out of the engine showing an even deep brown colour on the insulator nose and on the electrode. It also has no abnormal deposits that have built up.
If the spark plug is wet and has visible water droplets on it after removal from the engine, it might mean you have a compromised head gasket that is leaking.
A whitish powdery type of residue on the spark plug often means that the engine is being run with a lean air-fuel mixture.
Let’s look at the best possible ways to care for, remove, and replace your existing spark plugs.
Fit and remove
Installing and removing spark plugs needs to be done with care. Overtightening spark plugs or not cleaning the threads before replacing the new spark plugs is the common cause of thread damage.
It is advisable to hand tighten spark plugs to ensure they are properly threaded and then finish off the tightening with a spark plug spanner or torque wrench.
It is always advised to let the engine cool before the removal of the spark plugs. If the engine is too hot, the binding of the spark plug to the head can damage the thread.