May 5, 2026

RV Generator Maintenance During Storage: Prevent Costly Repairs

An RV generator that sits unused for months — without proper preparation — is one of the most common sources of expensive repair bills that owners face when they come out of storage. Carbureted and fuel-injected engines both suffer from stale fuel, varnish buildup, and dried-out gaskets during extended downtime. A generator that starts perfectly in October may need a $400–$800 carburetor rebuild by spring if it wasn't stored correctly.

Here's how to prep your generator before storage, what to do during storage, and how to bring it back online without problems.

Why Generators Fail During Storage

The primary culprit is fuel degradation. Modern gasoline contains ethanol blends that begin breaking down in as little as 30 days. As the fuel oxidizes, it:

• Forms varnish and resin deposits in the carburetor jets, float bowl, and fuel lines
• Separates into water-heavy and oil-heavy layers, with the water sinking to the bottom of the fuel system
• Leaves gummy deposits that clog small orifices and prevent the engine from starting

Diesel generators face different issues — diesel can gel in cold temperatures and grow microbial contamination (algae) in the tank over extended storage. But gasoline generators are far more common in RVs and face the greater short-term storage risk.

Pre-Storage Generator Prep: Step by Step

Step 1: Run It Under Load First

Before doing anything else, run your generator under load for 30–60 minutes. "Under load" means with appliances running — air conditioner, microwave, or electric space heater — not just idling. Running under load:

• Exercises the engine fully, burning off carbon deposits
• Circulates fresh oil through the entire system before the pre-storage oil change
• Identifies any issues (smoking, unusual noise, low output) before storage when they're easier to address

Step 2: Change the Oil

Change the oil before storage, not in spring. Used oil is acidic from combustion byproducts, and leaving acidic oil in contact with internal engine components for months causes corrosion. Most RV generators use small air-cooled engines that take 1–2 quarts of oil:

• Use the oil type and weight specified in your generator's owner's manual
• Change the oil filter at the same time
• Run the generator briefly after the oil change to circulate fresh oil

Step 3: Add Fuel Stabilizer

If your generator has a fuel tank (as opposed to drawing directly from the RV's main fuel tank), add a fuel stabilizer rated for at least 12 months:

• Products like STA-BIL, Star Tron, or PRI-G are effective choices
• Follow the dosage instructions on the product label — more is not better
• After adding stabilizer, run the generator for 10 minutes so the treated fuel circulates through the entire system, including the carburetor

Alternative: drain the fuel completely. If you prefer not to use stabilizer, running the carburetor dry is equally effective:

• Close the fuel shutoff valve (if equipped) and let the generator run until it starves and stops
• Remove the carburetor bowl drain plug (if accessible) and drain any remaining fuel
• A dry carburetor cannot develop varnish deposits

Step 4: Check and Replace the Spark Plug

Inspect the spark plug — if it shows heavy carbon buildup, erosion of the electrode, or is more than one season old, replace it now. A fresh plug costs a few dollars and eliminates one of the most common hard-start causes when you bring the generator out of storage.

Step 5: Check the Air Filter

Inspect the air filter element. A clogged filter causes rich running (too much fuel relative to air), which accelerates carbon buildup and makes starting difficult. Replace if dirty or if it's been more than one camping season since the last replacement.

Step 6: Clean the Exterior

• Brush or blow out any debris from the cooling fins and exhaust area
• Check that the generator compartment drain is clear
• Inspect the generator compartment for evidence of rodent activity — generators are warm, dark, and often smell of fuel, making them attractive nesting locations
• Place a rodent deterrent inside the compartment if your facility or home environment has rodent pressure

During Storage: Monthly Exercise

Even with proper pre-storage prep, generators benefit from being run briefly during storage. Most manufacturers recommend exercising the generator under load for at least 2 hours per month. This:

• Keeps seals and gaskets lubricated and prevents them from drying out and cracking
• Circulates oil through the engine preventing dry spots during the first start
• Charges the starter battery (if separate from the coach battery)
• Immediately surfaces any developing problems before you need the generator on a trip

If your storage facility has shore power access, some owners run their generator during periodic visits. If monthly visits aren't practical, the pre-storage stabilizer treatment becomes more important.

Bringing Your Generator Out of Storage

1. Check oil level before first start — top off if needed
2. Check fuel level and quality — if the fuel looks dark or smells stale, drain and replace
3. Let the generator warm up at no load for 5 minutes before applying load
4. Run under progressively heavier loads — start with a small appliance, then add the AC
5. If it starts hard or runs rough, check the spark plug and air filter before assuming a carburetor problem

A generator that was properly stored should start within 2–3 pulls (for pull-start models) or immediately on electric start. Hard starting after proper storage prep often indicates a fuel system issue that should be addressed by a small engine technician.