Generac GT-990 — Spark Plug Maintenance
Maintenance · Spark plugs
For the Generac GT-990, from the Generac owner's manual.
Applies to: Generac GT-990 engine
Procedure
- Clean the area around the base of the spark plugs.
- Remove the spark plugs and check condition; replace if worn.
- Check spark plug gap with a wire feeler gauge.
- Adjust the gap by carefully bending the ground electrode.
Tools required
- wire feeler gauge Amazon
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- Spark plug gap 0.76 mm (0.030 inch)
- Recommended spark plug RC14YC Amazon eBay $10.00 NAPA $4.94
Source: Generac owner's manual. Steps and values are as documented; always cross-check against the official manual and any later revisions for your exact serial number before servicing.