For Onan

Aftermarket Onan Parts & Accessories

In RV, marine, and off-road support power, Cummins Onan generator issues like hard starting, surging, fuel smell, hot shutdowns, or “cranks/no start.” Those symptoms often point to worn Onan parts—especially a weak fuel pump, clogged fuel/air filter, failed pressure switch, or tired start solenoid relay. Most customers come to us after repeated starts fail, fuel pressure drops, or safety systems trigger unexpectedly—clear signs that aftermarket Onan parts are due for replacement to restore stable operation.

To help you quickly resolve these issues, our Onon product line is comprehensive, making it easy for you to find suitable replacement parts.

Common Replacement Parts & Applications

FridayParts carries an extensive inventory of components compatible with popular Onan RV, marine, and commercial generator models such as HGJAA, HGJAD, HGJAE, and QG 4000/5500/8000 series.

Our hottest parts include:

• EFI fuel pumps for steady and efficient combustion.
• Thermostats to maintain correct operating temperatures.
• 12V start solenoid relays ensure quick engine starts.
• Water pumps are ideal for marine gensets like MDKBP, MDKBR, and MDKBV.
• Alternators for dependable charging performance.

When to Replace Your Onan Parts?

Regular wear and environmental factors can cause power instability or failure in Onan generators. Below are common indicators that it’s time for replacement:

• Difficulty starting or slower cranking (possible fuel pump or solenoid issue).
• Generator overheating (thermostat or water pump failure).
• Unstable fuel pressure (pressure switch malfunction).
• Irregular power output (alternator wear or clogged air filter).

Choosing high-quality aftermarket Onan parts from FridayParts can instantly restore power and reliability to your generator system.

Why Choose FridayParts?

At FridayParts, our aftermarket Onan parts combine OEM-level precision and tested durability with affordable pricing. Each item undergoes strict quality checks to meet international standards, ensuring consistent voltage delivery and performance under harsh conditions.

We serve operators of heavy equipment, RV systems, and marine vessels who rely on Cummins Onan generators to power daily operations.

Our key advantages include:

1. Large in-stock inventory – fast U.S. shipping to reduce machine downtime.
2. Wide compatibility – products fit vintage and modern Onan gensets.
3. Technical support – our experts assist customers with model selection and troubleshooting.