795259 Air Cleaner Primer Base with 491588S Air Filter for Most 122000 Model B&S Engines Toro Lawn Mower

What It Is

This is a combined air cleaner primer base (part 795259) and air filter (part 491588S) assembly for Toro lawn mowers powered by most 122000 model Briggs & Stratton engines. It replaces the worn-out primer bulb and dirty air filter in one drop-in unit, restoring proper air intake and primer function for reliable starting.

Fitment & Compatibility

• Engine types: Fits most Briggs & Stratton 122000 series engines (e.g., 122T02, 122E02, 122M07). Check your engine model number stamped on the blower housing or valve cover.
• Deck sizes: Typically found on 21–22 inch Toro walk-behind mowers (e.g., Recycler, Super Recycler) with B&S 122000 engines. Not for zero-turn or rider mowers.
• OEM vs aftermarket: This is a genuine Toro OEM part, so fit is exact for compatible models. Aftermarket equivalents may vary slightly in primer bulb stiffness.
• Measurements: The base is roughly 3.5 x 3.5 inches with a 1-inch primer bulb. The filter is 3.25 x 2.5 inches oval. Measure your old base to confirm.
• What to check before buying: Verify your engine model (not just mower brand) and that your current primer base has the same shape and mounting screw pattern (two screws, about 2 inches apart). Also confirm the air filter part number on your old unit is 491588S.

Key Things to Know

• Quality: OEM Toro plastic is durable; primer bulb feels firm but not brittle. Air filter is foam, washable, and reusable with oil.
• Installation difficulty: Easy—takes 5–10 minutes. Remove two screws, pull old assembly, drop in new one, and reinstall screws. No special tools.
• Common gotcha: The primer bulb can be stiff initially; prime 3–4 times before first start to seat it. Also, the filter must be oiled lightly with foam filter oil (or engine oil) before use to trap dust—don’t run it dry.
• Compatibility trap: Some 122000 engines use a different base (e.g., 795259 is for vertical shaft models; horizontal shaft models need a different part). Double-check your engine’s shaft orientation.

Should You Buy It

If your Toro mower with a B&S 122000 engine has a cracked primer bulb or a clogged, torn filter, this is the right fix. It’s a simple, affordable OEM replacement that restores starting reliability and engine protection. Avoid if your engine model isn’t on the list or if you prefer aftermarket filters—but for a direct fit, this is a solid choice.