Genuine Cummins Onan Green Label resistive spark plug for HGJAB and HGJAC (all fuel types, Spec A–K) and HGJAA (all fuel types, Spec A–K). Gap: 0.036". Cross-reference: NGK BPR4EY. Replace every 450 hours. Sold individually — two plugs required per generator. 1-year limited warranty.
The Cummins Onan 167-1638 is the OEM-specified resistive spark plug for HGJAB and HGJAC generators across all fuel system types and spec letters, and for all HGJAA variants including EFI, LP Liquid, and LP Vapor. It fits the RV QG 5500 and QG 7000 generator families — including the Marquis Gold, Marquis Platinum, and Emerald Advantage series.
The resistive design is not optional — it is a required specification for these generators. Using a non-resistive plug in place of this part can cause the generator to shut down without triggering a fault code, making the problem difficult to diagnose. Only Green Label resistive plugs meet Cummins Onan's specifications for these models.
These are two-cylinder engines. Two plugs are required per generator — one per cylinder. This listing is sold individually; order two for a complete service.
Resistor design is mandatory for HGJAA/HGJAB/HGJAC generators — non-resistive plugs cause shutdowns without fault codes, making failures hard to diagnose
Set to 0.036" gap for all HGJAA, HGJAB, and HGJAC generator models across all fuel types — gasoline, LP liquid, and LP vapor
OEM Cummins Onan plug cross-references to NGK BPR4EY — use only resistive equivalents that meet the same specifications
HGJAA/HGJAB/HGJAC are two-cylinder engines — one plug per cylinder; order two for a complete plug change at the 450-hour service interval
The HGJAA, HGJAB, and HGJAC generators require a resistive spark plug. Installing a non-resistive plug — even one with the correct thread and heat range — can cause the generator to shut down without generating a fault code. This makes the failure appear as a no-start or unexpected shutdown with no diagnostic indication, leading to unnecessary troubleshooting and service calls. Always use Cummins Onan Green Label part 167-1638 or a confirmed resistive equivalent (such as NGK BPR4EY). Do not substitute standard non-resistive plugs.
• One (1) 167-1638 Resistive Spark Plug Note: HGJAA, HGJAB, and HGJAC generators require two (2) spark plugs — one per cylinder. This listing is sold individually. Add two to your cart for a complete plug service.
Backed by a 1-year limited manufacturer's warranty against defects in materials and workmanship. Cummins Power Generation warrants only the quality and integrity of Green Label Parts. Damage caused by the use of non-Green Label or non-resistive spark plugs is not covered under the Cummins Onan limited warranty.