698369 Air Filter Tune Up Service Kit with 694394 Primer Bulb 795083 495770 Diaphragm Gasket for BS 550 400 450 300 and 500 Series, 3.5HP 3.75HP 4.5HP 4.75HP Classic Sprint Quattro Engines

What It Is

This is a multi-part tune-up kit for Briggs & Stratton (BS) Classic, Sprint, and Quattro engines in the 300, 400, 450, and 500 series (3.5HP to 4.75HP). It includes an air filter, primer bulb (694394), and two diaphragm/gasket seals (795083/495770) to restore fuel system and air intake performance.

Fitment & Compatibility

Before buying, check:

• Engine series: Only fits BS 300/400/450/500 series engines with 3.5HP, 3.75HP, 4.5HP, or 4.75HP ratings. Not for larger Intek or Vanguard models.
• Primer bulb: Replaces OEM 694394 – confirm your primer bulb is the same push-in style with a flat base.
• Diaphragm/gasket set: Replaces 795083 and 495770 – these are common on carburetors with a two-piece fuel pump cover.
• Measurements: Air filter outer dimensions are roughly 4.5" x 3.5" x 1.5". Measure your old filter to confirm.
• OEM vs aftermarket: This is an aftermarket kit. It works well for most, but OEM parts are slightly more durable for heavy-use mowers.

Key Things to Know

• Installation difficulty: Easy (15-20 minutes). No special tools – just a screwdriver and pliers for the primer bulb.
• Quality: Many users report the primer bulb is softer than OEM, but it seals correctly. The air filter fits snugly – no gap issues.
• Common gotcha: The diaphragm gaskets are thin and tear easily. Install gently and ensure the carburetor body is clean before seating.
• Missing parts: Some kits may lack the small foam pre-filter. If your engine has one, order separately.

Should You Buy It

Yes, if you have a BS 300-500 series engine and want a budget-friendly tune-up for one season. It’s ideal for DIY maintenance on push mowers, pressure washers, or small generators. Skip it if you need OEM durability for commercial use or if your engine uses a different primer bulb design.