Glow Plugs
(From RC Universe Forum)

Your glow plug temperature range is TOO COLD when:

  • The engine power is weak or has weakened from previous levels
  • The engine slows down considerably or stops after removing the glow plug battery despite correct adjustment of the needle valve

Your glow plug temperature range is TOO HOT when:

  • The engine suffers from pre ignition and a loss of power
  • The overall engine running is rough
  • The glow plug filament is broken or collapses frequently

Glow Plug RULES:

  • If engine RPM immediately drops when the glow starter is removed, you may need a new glow plug, a hotter plug, or more nitro
  • If the engine backfires alot, you may need a cooler plug or less nitro


  • HOT GLOW PLUGS (Low nitro and FAI fuels)
    • Enya #3
    • Fox: Miracle, Standard, and R/C Long (2 Volt)
    • Fireball: Hot(1.2 - 3.0 Volt) and S-20 R/C Long
    • Fire Power: F6 (Warm) and F7 (Hot)
    • K&B: 1L
    • McCoy: MC55 R/C Long, MC59, and MC14 (Very Hot)
    • OS Engines: #0, #1, and #5
    • Rossi: R1 (Extra Hot)
    • Sonic Tronics: Glow Devil #300
    • Thunderbolt: R/C Long

  • MEDIUM GLOW PLUGS (10 - 15% nitro fuels)
    • Enya #4 (Medium Hot) and #5 (Medium Cold)
    • Fox: R/C Long (1.2 - 1.5 Volt) and Gold
    • Fireball: Standard (1.2 - 2.0 Volt)
    • Fire Power: F5 (Medium) and F6 (Warm)
    • Hangar 9: Sport Long
    • McCoy: MC50 and MC8
    • OS Engines: #A3, #8, #9, #7 (with idle bar)
    • Rossi: Medium and R3
    • Sonic Tronics: Glow Devil Standard
    • Tower Hobbies: Tower Power Performance plug and Regular (with idle bar)

  • COLD GLOW PLUGS (25+ % nitro fuels)
    • Enya #6 (Cold)
    • Fox: R/C Long (1.2Volt) and #8
    • Fireball: Cool (1.2 - 1.5 Volt)
    • Fire Power: F2 (Extra Cold), F3 (Cold), and F4 (Cool)
    • K&B: Long and Short High Performance Nitro Plug
    • McCoy: MC9
    • OS Engines: R5
    • Rossi: R4 (Cold) and R5 (Extra Cold)

    • Fox: Miracle Plug (Often used in 2 strokes with low nitro)
    • McCoy: MC14 (Very hot, often used in inverted 4 strokes)
    • OS Engines: Type F
    • Sonic Tronics: Glow Devil ST 301 and 302

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