Changing spark plugs

Why would you need to change spark plugs?

A spark plug’s performance can deteriorate over time and will need replacing periodically depending on how much and how the motor is used. Indications of faulty spark plugs included such as issues a hard starting the motor, misfire, rough idling, decreased fuel economy and sluggish acceleration. You may also need to change spark plugs due to an IRB rollover (submersion in water) or due to flooding the motor.

How to change spark plugs

!Do not reuse spark plugs with damaged insulation as sparks can leak through the crack potentially leading to electric shock, explosion or fire.

Do not touch spark plugs immediately after stopping the motor as they will be hot and could cause severe burns if touched.

Allow motor to cool down prior to removal.

*Use only the recommended spark plugs as per the Manufacturer.

The use of spark plugs other than those specified may have a different heat range and may cause damage to the motor.

If the spark plug(s) is fouled, i.e. has carbon build up or is worn, it should be replaced. When reusing spark plugs, remove all carbon deposits from the electrodes and adjust the spark gap as per the manufacturer’s specifications.

1. Ensure the IRB kill switch is in the off position.
2. Remove the cowling from the motor.
3. Remove the spark plug caps from the spark plugs.
4. Remove the old spark plugs by turning counter – clockwise using a 21mm socket wrench.
5. Inspect the spark plug. Clean, and check electrode gap using feeler gauges (both Tohatsu and Mercury recommend a gap of 0.09 -1.0mm) / replace as necessary (Both Tohatsu and Mercury recommend NGK B7HS-10 or BRZHS10 Spark plugs)

6. Insert cleaned/new spark plugs, tighten by hand turning counter-clockwise to avoid cross threading.

Note: the spark plug is fitted with a crush washer and should not be over tightened

7. Tighten the spark plug (s) using a 21mm socket wrench and torque to the manufacturer’s specification e.g. for both Tohatsu and Mercury the Tq is 27Nm.
8. Replace the spark plug caps.
9. Attempt to restart the motor as per normal motor starting procedures.