Description
Product Overview
Keep your Onan QG generator starting on the first crank with these premium replacement spark plugs. Direct replacement for Onan part number 167-1638, these plugs are engineered for the high-hour duty cycles of RV generators.
Compatible with Onan QG 5500 and 7000 models (HGJAA, HGJAB, HGJAC). Worn spark plugs are the #1 cause of hard starting and rough running in RV generators — replace annually or every 150 hours for reliable performance.
Key Features
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Direct OEM Replacement — Replaces Onan 167-1638
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Nickel-Plated Shell — Anti-seize and corrosion-resistant
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Copper-Core Electrode — Superior heat dissipation and conductivity
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Pre-Gapped — Factory-set to OEM specification; ready to install
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Pack of 2 — Both plugs for twin-cylinder QG generators
Compatibility
| Generator Model |
Spec Codes |
Power |
| Onan QG 5500 |
HGJAA, HGJAB, HGJAC |
5,500W |
| Onan QG 7000 |
HGJAA, HGJAB, HGJAC |
7,000W |
Specifications
| Specification |
Value |
| Part Number |
167-1638 |
| Thread Size |
14mm x 1.25 |
| Reach |
19mm (3/4") |
| Hex Size |
5/8" (16mm) |
| Gap |
Pre-gapped to OEM spec |
| Quantity |
2 Pack |
Frequently Asked Questions
Q: How often should I change generator spark plugs?
A: Onan recommends spark plug replacement every 150 hours or annually, whichever comes first. If your generator sees heavy use or runs in dusty conditions, consider more frequent replacement.
Q: What are signs my spark plugs need replacing?
A: Hard starting, rough idle, surging under load, increased fuel consumption, or visible electrode wear/carbon fouling on inspection.
Q: Does this pack include 2 plugs?
A: Yes, this is a 2-pack — enough for both cylinders on the QG 5500 and 7000 twin-cylinder generators.
Q: Are these pre-gapped?
A: Yes, factory pre-gapped to OEM specification. Always verify gap before installation as a best practice, but they should be ready to install out of the box.
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