Stens 785-505 Engine Tune-Up/ Maintenance Kit For Briggs & Stratton 5106B Quantum 3.5 - 6.5 HP

What It Is

The Stens 785-505 is a complete tune-up/maintenance kit for Briggs & Stratton Quantum 3.5 to 6.5 HP engines (model 5106B). It includes a spark plug, air filter, fuel filter, and oil—everything needed for a single seasonal servicing of walk-behind mowers.

Fitment & Compatibility

• Engine models: Briggs & Stratton Quantum 3.5–6.5 HP with model type 5106B (check engine code stamped on valve cover or blower housing).
• Not universal: Does not fit Intek, Endurance, or older Briggs flathead engines. Confirm your engine’s model number starts with “5106.”
• OEM vs. aftermarket: Stens is a respected aftermarket brand; parts are direct replacements for OEM Briggs & Stratton 5099, 5098, and 5097 filter/spark plug numbers.
• Measurements: Spark plug gap is pre-set (0.030 in.), but verify with a gap tool. Air filter is a standard foam pre-cleaner + paper element—check it matches your mower’s air cleaner housing.
• Oil included: 20 oz. SAE 30 (typically 4-cycle)—enough for most Quantum engines. If your mower takes 5W-30 or synthetic, you’ll need separate oil.

Key Things to Know

• Installation difficulty: Easy—15-20 minutes with basic hand tools (socket wrench for spark plug, screwdriver for filter covers). No special skills required.
• Quality: Stens parts are durable and meet OEM specs. The spark plug is a copper-core; not iridium, but fine for standard mowers.
• Common gotcha: The fuel filter is inline—if your mower has a different diameter fuel line (common on older models), you may need an adapter or separate filter.
• Cost value: At ~$26, it’s cheaper than buying OEM individually (typically $35+), but check if you already have oil or prefer a different viscosity.

Should You Buy It

Yes, if you own a Briggs & Stratton Quantum 3.5–6.5 HP mower (model 5106B) and want a simple, all-in-one kit for annual maintenance. It’s a solid value for DIYers—just verify your engine model and fuel line size before buying. Skip if you need synthetic oil or a different plug type.