How to Start Onan RV Generator

RVs allow you the freedom of the open road and the comforts of home. But enjoying all the modern conveniences while off-grid requires power – RV generators supply that power. Onan is the most trusted name in RV generators. Used in motorhomes for over 50 years, Onan generators reliably provide safe and quiet power for appliances and electronics.

But starting up an Onan RV generator involves more than just turning a key. Follow this guide to learn the proper procedures for pre-start checks, starting, operating and shutting down your Onan generator to keep it running optimally. I’ll also cover troubleshooting common issues and maintenance tips for longevity. Whether you’re a new RV owner or seasoned motorhome operator, use this comprehensive tutorial for everything you need to confidently start your Onan RV generator.

How to Start Onan RV Generator

Overview of Onan RV Generators

Onan is a Cummins Inc. brand that manufactures generators specifically engineered for recreation vehicles. Onan generators supply electrical power for RVs through gasoline/diesel engines or propane fuel converted to electricity by a generator.

Onan RV generators provide clean, quiet power to run air conditioners, microwaves, TVs and other appliances when camping off-grid. The convenience of electricity for motorhome comforts makes Onan the most popular RV generator brand.

Common Onan RV Generator Models

Onan offers generator models in a range of sizes to meet every RV’s power needs:

a. Cummins Onan QG 2500- Small and lightweight 2.5kW generator ideal for quick overnight dry camping. Runs up to 8 hours on gasoline.

b. Cummins Onan QG 2800 – 2.8kW midsize generator powers an RV air conditioner plus additional appliances. Dual-fuel option (gasoline/propane).

c. Cummins Onan QG 4000- Large 4kW unit supplies 30 amps for bigger motorhomes. Quietest RV generator available. 

d. Cummins Onan QG 5500- Commercial-grade 5.5kW generator for the largest motorhomes with multiple A/Cs and high electrical demand.

Now that you’re familiar with Onan and its RV generator models, let’s look at the steps before starting your Onan. Later that I’ll discuss the starting procedure of the onan RV generator. Stay with me till the end of the article.

Before Starting the Onan RV Generator

Before turning the key, you must make some checks and inspections to ensure a safe and successful generator starting. Rushing into starting your RV generator without proper preparation often leads to issues down the line.

Step-01: Check the Oil Level 

Checking the oil level is the most critical pre-start check. The dipstick allows you to verify oil level is correct for engine lubrication.

Look for oil level between the “L” (low) and “H” (high) markers on the dipstick. If oil is low, add the recommended oil type to reach the proper level. 

Proper oil level is crucial because oil lubricates the generator’s internal moving parts. Without enough oil coating components, the engine could seize up and suffer catastrophic damage.

Step-02: Check the Fuel Level

It’s obvious your generator needs adequate fuel supply to run. But a too-low fuel level causes problems beyond just stalling out.

Gasoline helps cool the fuel pump. Running the pump dry from low fuel can overheat the component and cause premature failure.

So always check your Onan generator’s gas tank level before starting. Top off the tank with fresh unleaded gasoline if low. This prevents frustrating stalls and protects the fuel pump.

Step-03: Inspect Air Filter

Proper air flow is directly related to generator performance. Dirty, clogged air filters restrict air intake and choke the engine.

Remove the cover and check that the air filter is clean and intact. If excessively dirty, replace the filter. This allows smooth, unrestricted airflow into the combustion chamber.

Tip: Always keep spare air filters on hand. Inspect every 25 hours and replace as needed.

Step-04: Check for Leaks

Leakage of fuel, oil or exhaust can create hazardous conditions and lead to generator damage if not addressed quickly.

Look under the generator for any fuel, oil or exhaust leaks before starting up. Fuel leaks present a serious fire hazard. Oil leaks cause improper lubrication. Exhaust leaks could allow carbon monoxide into the RV living space. 

Always fix any leaks before operating the generator. Leaks left unresolved grow worse over time and lead to bigger problems. Contact your dealer if repair assistance is needed.

Step-05: Battery Inspection

If you haven’t used your RV generator in a while, the starter battery may be too depleted to turn over the engine.

Assess the battery condition before attempting to start the generator. Check charge level if possible. Connect to an external power source for recharging if battery voltage seems low.

A good RV generator battery is critical for easy starting. Replace the battery every 3-4 years or sooner if troublesome cranking occurs.

Starting the Onan RV Generator

Once your pre-start checks and inspection are complete, you’re ready to get the generator running with these starting procedures.

Step-01: Prime the Fuel Line

Fuel left stagnant in the lines and carburetor from sitting periods can make starting difficult. Priming clears any dried gas and preps the system.

Turn the generator key to “On” without cranking the engine. Allow the fuel pump to run for 60 seconds to prime the lines and carburetor with fresh fuel.

Priming before starting ensures immediate engine firing without hesitation or stumbling. It’s a simple step that guarantees smooth starting.

Step-02: Start Generator

With fuel lines primed, turn the generator key fully to the “Start” position. This engages the starter motor to crank the engine.

If the engine doesn’t start after 5 seconds of cranking, stop and wait 30 seconds before trying again. Excessive cranking can overheat the starter windings. The pause allows things to cool.

Once started, let the key return to “On” and keep running to charge the battery. The generator should immediately run smoothly with no shaking or rattling noises.

Step-03: Let Generator Warm Up

When first started, the engine RPM runs higher to warm the generator. This initial “fast idle” period lasts 3-5 minutes. 

Allow the generator to warm up completely before connecting any electrical loads or appliances. Warming up stabilizes operating temperature and allows systems to synchronize. 

Don’t leave the generator unattended during warm-up. Check for any leakage, smoke or abnormal noises that could indicate problems.

Step-04: Connect Electrical Load

With the generator running and warmed up, you can now connect appliances and devices.

Start by turning on essential items first, like the RV air conditioner. Gradually add additional load. Avoid connecting too many things at once to prevent overloading the generator.

Monitor power output and load. If voltage drops or frequency fluctuates, reduce the electrical load on the generator.

Shutting Down the Onan RV Generator

You’ve started the generator successfully and powered your RV. Now let’s look at the proper way to shut down your Onan when finished.

Proper Shutdown Procedure

Abruptly shutting off an RV generator without a cool down period stresses the engine and generator windings. Follow shutdown steps:

Turn off air conditioners and appliances. Let the generator run 3-5 minutes with no electrical load for cooling down.

Turn the fuel valve to “Off”. Keep the generator running until it uses up remaining fuel and stalls out. This prevents fuel varnishing in the carburetor.

Allow the generator to fully cool before cleaning or covering. Never store a hot generator, which can lead to fire.

Post-Operation Checklist

Certain checks after shutting down help keep your Onan generator running great for years:

Check for leaks or unusual smells – Signs of trouble if issues arise.

Note any abnormal noises – Helps diagnose problems during future generator runs.  

Log run time – Allows you to track maintenance schedules.

Check oil level – Top off if low to prevent dry starts.

Establish a post-run checklist for your generator model and follow it consistently. This ensures every outing ends on a high note.

Troubleshooting Common Onan RV Generator Issues

Even well-maintained RV generators can sometimes experience problems. Here’s help diagnosing and resolving the most common Onan generator failures.

A. Failure to Start

An Onan generator failing to start or crank could stem from several causes:

Weak battery– Charge battery or jump start generator if below 10 volts.

No fuel – Fill empty fuel tank to troubleshoot. Prime fuel line after filling.

Faulty spark plug – Remove plug and check for fouling or cracked porcelain. Replace if needed.

Overcranking – Wait 30 seconds between start attempts to avoid overheating the starter. 

Use a diagnostic service tool to pull any engine fault codes if generator cranks but won’t start.

B. Maintenance Tips

Lack of maintenance usually underlies most generator problems. Follow these tips:

Check oil level regularly and fix any leaks immediately.

Change oil and filters per the maintenance schedule recommendations.

– Inspect spark plugs and replace annually or after 250 running hours.

Clean air intake and replace air filters as needed.

Use fuel stabilizer to prevent stale gasoline from fouling carburetors. 

Exercise the generator monthly with a 30-minute loaded run.

Regular professional service by an Authorized Onan Dealer annually or every 100-200 hours keeps your generator in top operating condition. Don’t skimp on maintenance.

Safety Tips for Onan RV Generators

While very safe when properly operated, Onan generators require some basic safety practices:

Always start and run the generator in a well-ventilated outdoor area. Never operate a generator inside an RV or confined space, which could cause deadly carbon monoxide poisoning very quickly.

Turn the generator off and let cool completely before refueling. Gasoline spilled on hot components creates a fire hazard.

Check for exhaust leaks regularly. Leaking exhaust allows toxic carbon monoxide into living spaces and can be fatal. Test CO detectors monthly.

Exercise the generator monthly to keep the engine seals, hoses, and moving components conditioned. Stagnant generators are prone to premature failures.

Following basic safety protocols when using your RV generator keeps your travels safe and enjoyable. Consult your owner’s manual for model-specific safety instructions.

More Queries

Q1: How often should I start and run my RV generator?

A: It’s recommended to start and exercise your generator at least monthly for around 30 minutes under 25-50% of rated load. This prevents stagnation and keeps components lubricated.

Q2: Where is the best place to start my Onan RV generator?

A: Always start and operate the generator outdoors in an area with good airflow and ventilation. Never run a generator inside an RV or enclosed space.

Q3: Can I use a portable generator to charge my RV’s house battery?

A: Yes, you can recharge an RV battery using a portable generator. Ensure the generator provides clean power above 50 volts A/C to prevent damage.

Q4: What oil type should I use in my Onan RV generator?

A: Most Onan generators use 10W-30 or 5W-30 synthetic motor oil. Always verify the oil type for your specific Onan model in the owner’s manual.

Q5: Why does my generator emit white or blue smoke when running?

A: White/blue smoke indicates burning oil, likely from worn piston rings or valve seals. Have an authorized dealer inspect and repair any oil leaks promptly. 

Q6: My generator runs fine but won’t output electricity – why?

A: If the engine runs but has no electric power, the generator rotor may be bad. Contact an Onan dealer to diagnose and repair the generator winding components.

Q7: What should I do if my RV generator won’t start at all?

A: Begin basic troubleshooting – check battery charge, verify fuel level, inspect spark plug. If issues persist, have an Onan service tech inspect and test components.

Final Words

Starting an Onan RV generator requires following proper procedures for pre-checks, priming, starting, warm-up, loading and shutdown. Practicing these steps regularly develops familiarity and prevents mistakes. Getting comfortable with the start-up process ensures you can quickly and reliably power up your motorhome appliances anytime off-grid.

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