LIZAPUS 69731 Primer Bulb & Fuel Line Kit Compatible with YRato Predator RV170 173cc 5.5HP Vertical Engine 16100-Z340910-0099 DB2321SR 21'' 170cc RV170 RV170-S

What It Is

This is a replacement primer bulb and fuel line kit designed to restore the priming function on small engines, specifically for YRato, Predator, and similar vertical shaft engines like the RV170 173cc 5.5HP. It fixes hard-starting issues caused by a cracked or collapsed primer bulb or degraded fuel lines.

Fitment & Compatibility

Before buying, verify your engine is a YRato RV170, RV170-S, or Predator 173cc 5.5HP vertical shaft model. The kit includes a primer bulb, fuel line, and grommet that match OEM part 16100-Z340910-0099. It fits mower decks like the DB2321SR 21” but deck size alone doesn’t guarantee fit—check the engine model number (usually stamped on the engine shroud or valve cover). This is an aftermarket kit, not OEM, but dimensions should match. Measure your existing bulb diameter (typically ~1 inch) and fuel line inner diameter (often 3/16” or 1/4”) to confirm compatibility. Not intended for horizontal shaft engines or non-YRato/Predator brands.

Key Things to Know

• Quality: Users report a solid fit and good rubber compound—no premature cracking reported in early reviews, but aftermarket bulbs may degrade faster than OEM in extreme sun or cold.
• Installation difficulty: Easy (15-30 minutes) for DIYers; requires removing the air filter cover and carburetor shroud. No special tools, but needle-nose pliers help disconnect old fuel line.
• Common gotchas: The fuel line can be stiff when cold—dip in hot water to soften. Ensure the grommet seats fully in the carburetor cover to prevent air leaks. If your mower has a separate fuel filter, this kit doesn’t include one; replace it separately.
• Check fuel line length: The kit includes a pre-cut length, but if your routing is unusual, you may need to trim or source additional line.

Should You Buy It

If you own a YRato RV170 or Predator 173cc engine and need a quick, inexpensive fix for a failed primer bulb, this kit is a solid buy. It’s a direct-fit replacement at a fraction of OEM cost, with straightforward installation. Avoid if you need a bulb for a different engine brand or if your fuel line has additional damage beyond the primer system.