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Tillotson 24B-449 Idle/High Speed Mixture Screw Spring
24B-449 Tillotson Idle/High Speed Mixture Screw Spring
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Tillotson 24B-449 Idle/High Speed Mixture Screw Spring

Part Number: 24B-449
Online Price: $1.29
Tillotson 24B-449 OEM Mixture Screw Spring for Idle & High-Speed Adjustments
Availability: In Stock.

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Description

Tillotson 24B-449 OEM Mixture Screw Spring – For Idle and High-Speed Adjustment Screws


The Tillotson 24B-449 Mixture Screw Spring is a genuine OEM replacement component that provides essential tension to your carburetor’s high-speed and low-speed mixture screws. This spring ensures the adjustment screws remain securely seated, preventing them from vibrating loose during engine operation.

Maintaining proper tension on your mixture screws is critical for consistent fuel metering, optimal engine performance, and safe operation.


Key Features:

  • OEM Part Number: 24B-449
  • Function: Applies tension to idle (low-speed) and high-speed fuel mixture screws
  • Use Case: Prevents screws from backing out due to engine vibration
  • Material: Spring steel, corrosion-resistant
  • Application: Fits both high and low side screws in compatible Tillotson diaphragm carburetors


Troubleshooting Note:

If your mixture screws are adjusted more than 3 full turns out, this may indicate:

  • Incorrect carburetor application
  • Internal carburetor damage or wear
  • Fuel delivery issues (such as poor pump pressure or clogged circuits)

Caution: Running screws more than 3 turns out can allow them to back out during operation, which may lead to engine damage. If needed, an additional mixture screw washer can help temporarily improve spring tension—but this is not a permanent fix.

When in doubt, consult a qualified engine builder or carburetor technician.


Compatible Tillotson Carburetors Include:

This spring fits a broad range of Tillotson HL, HR, HW, HX, HD, HB, HC, and HM series diaphragm carburetors, including:


Popular Models:
HL-1A, HL-132H, HL-166B/C, HL-227A/E, HL-250A–E, HL-274E, HL-292G, HL-304E/WX/WXA/WXG, HL-334A–AB, HL-348A–E, HL-355A–E, HL-366A, HL-371A, HL-385A, HL-388A, HR-181B, HR-190A, HR-196A, HW-10A–HW-43A, HX-10A, HM-1A, and many more.

Note: Always confirm fitment with your specific carburetor model or service manual.


Ideal For:

  • Engine builders and tuners
  • 2-cycle carburetor rebuilds
  • Small engine repair professionals
  • Replacing weak or missing spring tension in high/low mixture screws

FAQ

Q1: What does the Tillotson 24B-449 spring do?

A: It adds tension to the high-speed and low-speed mixture screws in your Tillotson carburetor, ensuring they stay securely in place and don’t loosen due to engine vibration.


Q2: How do I know if my spring needs replacing?

A: If your mixture screws won’t hold their setting, or if they back out on their own after adjustment, the spring may be worn, stretched, or missing.


Q3: Can I use this spring on both the high and low-speed screws?

A: Yes. The 24B-449 spring is designed to work with both the idle (low-speed) and high-speed mixture screws in compatible Tillotson diaphragm carburetors.


Q4: What if my screw needs to be turned more than 3 turns out to run properly?

A: That often points to a deeper issue—such as incorrect carburetor sizing, worn internal parts, or poor fuel delivery. It’s not a spring issue. Adding a second washer can help temporarily, but this is not a long-term solution.


Q5: Which Tillotson carburetors does the 24B-449 fit?

A: It fits a wide range of HL, HR, HW, HX, HM, HB, HC, and HD series Tillotson diaphragm carburetors—used in chainsaws, karts, small engines, and more. Always confirm your model or consult a service manual.


Q6: Is this spring included in rebuild kits?

A: Some kits may include it, but if you're unsure or replacing mixture screws individually, it’s best to order the spring separately to ensure proper tension and performance.

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