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Dennis RossJul 30, 2025
Why is my Ryobi 990r Trimmer engine difficult to start?
- RRobert HuntJul 30, 2025
If your Ryobi Trimmer engine is hard to start or won't start, first ensure the ignition switch is set to “RUN (I)”. Other potential causes include: the primer bulb not being pressed enough (press it fully and slowly 5-7 times); the engine not being choked (use the starting procedure with “FULL” CHOKE); an empty fuel tank (fill it); a flooded engine (use the starting procedure with “PARTIAL” CHOKE); valve clearance out of adjustment (adjust valve to rocker arm clearance); a plugged spark arrester screen (clean or replace it); or a fouled spark plug (clean, regap, or replace it).