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Tillotson HW 48g Inlet Tension(Pop-Off) Spring
24B-345 Tillotson Inlet Tension Spring
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Tillotson HW 48g Inlet Tension(Pop-Off) Spring

Part Number: 24B-345
Online Price: $1.79
Tillotson 24C-296 48g Inlet Tension Pop-Off Spring
Availability: In Stock.

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Description

24C-296 Tillotson HW 48g Inlet Tension (Pop-Off) Spring – OEM Precision Spring for 2-Cycle Diaphragm Carburetors


The Tillotson 24C-296 48g Inlet Tension Spring is a genuine OEM pop-off spring engineered to fine-tune fuel delivery in high-performance 2-stroke racing engines. Designed specifically for Tillotson HW, HL, HM, HB, HC, HR, and HX carburetors, this heavier 48-gram spring increases pop-off pressure, causing the inlet needle to open later and slightly leaning the fuel mixture—ideal for high-RPM and crisp throttle applications.


Compared to the more common 31g, 42g, or 46g springs, the 48g version allows more precise control over low-end fuel delivery, helping prevent rich conditions at idle or off-throttle transitions.


Key Features:

  • OEM Tillotson Part #24C-296
  • 48g spring tension for higher pop-off pressure
  • Optimized for 2-cycle diaphragm carburetors
  • Common in karting, ultralight aircraft, saws, and small race engines
  • Fine-tunes fuel response at low to mid RPMs


Pop-Off Tuning Tip:

Set pop-off pressure as low as possible while still achieving a clean, snappy throttle response—especially critical in corner exits. Too low, and you’ll experience bogging or over-richness. Too high, and throttle hesitation or fuel starvation may occur.

Always:

  • Tune pop-off after setting needle screws
  • Use fresh diaphragms for accurate readings
  • Adjust using springs, fulcrum arm height, or install shims


Important Note:

Pop-off pressure ? fuel pressure. Fuel pumps typically generate only ~1 PSI. Pop-off measures when the needle opens—not the pressure required to run the engine.


Compatible Carburetor Models:

  • Tillotson HW Series
  • HB, HC, HL, HM, HR, HX Series


Why Racers Choose the 24C-296 Spring:

Reliable pop-off behavior. Precise low-RPM fuel control. Better consistency on technical tracks. It’s the go-to choice for tuners demanding peak carburetor performance under race conditions.

FAQ

Q1: What does a 48g pop-off spring do?
A: It increases the pop-off pressure, delaying when the needle opens—leaning out the fuel mixture for more precise tuning.


Q2: Is this spring compatible with my carb?
A: It fits most Tillotson HW, HL, HB, HC, HM, HR, and HX carburetors. Check your model or consult a tech guide.


Q3: Can I use this on a 4-cycle engine?
A: It’s optimized for 2-cycle diaphragm carbs. While it may fit some setups, it’s not typically used on 4-cycle carburetors.


Q4: How do I adjust pop-off pressure with this spring?
A: You can swap springs, adjust fulcrum arm height, or add shims under the spring to increase pressure in small increments.

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