TLDR
- Run your generator monthly under load - the #1 reliability tip
- Annual oil, filter, plug service is $175 to $350 in PSL
- Onan QG and Cummins are the two most common RV gensets
- Snowbird storage habits cause most generator failures
- Call 772-276-6465 for mobile service across PSL
Onan and Cummins generators power most Class A and Class C motorhomes parked across Port St. Lucie. The Onan QG (3.6, 4.0, 5.5 kW) is the workhorse on Tiffin, Winnebago, and Thor coaches. Cummins Onan diesel units run on the bigger rigs. Both are reliable when maintained and expensive to fix when neglected. The single biggest factor in generator longevity in PSL is whether the owner runs it monthly during snowbird storage.
The Monthly Run Rule
Run your generator for 30 minutes once a month, under load (turn on the rooftop AC). This does three things: keeps the carburetor clean of fuel varnish, keeps the brushes seated against the slip rings, and exercises the fuel pump and lines.
Snowbirds who park in Tradition or PGA Village in April and don't return until October come back to a generator that won't start. The fuel has gummed up the carb, the battery is dead, and the brushes are pitted. A 30-minute monthly run prevents all three.
Annual Maintenance Schedule
Every 150 hours or annually (whichever comes first): oil and filter change, air filter replacement, spark plug inspection. Onan oil capacity is 1.6 to 2 quarts depending on model - use 15W-40 in Florida heat.
Every 500 hours: spark plug replacement, valve adjustment, fuel filter replacement. We do this during a single 2-hour visit and load-test afterward to confirm full output. Our generator tune-up service covers all of the above.
Common Failure Modes in PSL
Carb varnish from non-ethanol fuel sitting too long: $150 to $300 to clean, $400 to $600 if rebuild is needed. Fuel filter clogging: $50 to $100. Brush wear: $200 to $400. Voltage regulator failure: $300 to $500.
Florida humidity also causes corrosion at the AC output connections - we always inspect and clean during service.
Load Testing
After any service, we run a load test: connect to shore-power line, measure voltage and frequency at 25%, 50%, 75%, and 100% rated load. Voltage should hold within 5% across the range, frequency within 1Hz of 60Hz.
Generators that test out of spec usually need carb adjustment, fuel system service, or governor work. We diagnose on site - see our load testing service for details.
When to Repair vs Replace
Onan QG units in good shape are worth fixing up to about $1,500 in repairs. Past that, swapping in a new 4kW Onan or a Cummins KY runs $4,000 to $6,500 installed. Diesel pusher generators (Cummins HDKAJ, Onan 7500) are bigger jobs - $8,000 to $12,000 for replacement. Most owners service rather than replace until 3,000+ hours. Schedule generator service at 772-276-6465 - we handle Onan and Cummins units across all of St. Lucie County.