2-Pack 753-08319 3 Line Primer Bulb Replacement for Craftsman 316731932 316731933 316731934 316740930 316740970, Troy-Bilt TB6044XP TB635EC TB685EC

What It Is

This is a 2-pack of 753-08319 primer bulbs designed for gas-powered trimmers and blowers from Craftsman and Troy-Bilt. The bulb primes the carburetor by forcing fuel into the system, making cold starts easier on handheld 2-cycle engines.

Fitment & Compatibility

Before buying, confirm your model number matches exactly: Craftsman 316731932, 316731933, 316731934, 316740930, 316740970; Troy-Bilt TB6044XP, TB635EC, TB685EC. This is an aftermarket part, not OEM, but it’s built to the same 3-line configuration. Measure your old bulb’s outer diameter (typically ~1 inch) and ensure the two mounting holes align with your housing. The bulb itself is about 0.75 inches tall. It fits most Troy-Bilt and Craftsman trimmers with a similar primer bulb retaining ring, but not all—double-check that your machine uses a 3-line (not 2-line) bulb design.

Key Things to Know

• Quality: Users report it works as well as OEM for about half the price, but some note the rubber feels slightly stiffer than original. It should last a season or two with regular use.
• Installation: Easy DIY—remove the old bulb by prying off the retaining ring, pull it out, push the new one in, and snap the ring back. No tools required beyond a small flathead screwdriver.
• Gotcha: The retaining ring can be brittle on older machines; have a spare or be gentle when removing it. If the carburetor is gummed up, replacing the bulb alone won’t fix starting issues.
• 2-pack value: You get a spare, which is smart since these bulbs degrade over time from fuel exposure and UV.

Should You Buy It

If you own one of the listed Craftsman or Troy-Bilt trimmers and your primer bulb is cracked, collapsed, or not holding prime, this is a cheap, reliable fix. It’s ideal for DIY homeowners who want to avoid a service shop. Skip it if your machine uses a different bulb type or if the carburetor needs a full rebuild.