The Generator Exercise Schedule Nobody Follows and What It Costs

The most common generator complaint we get is that it will not start. The most common cause is that it has not been run.

Generators are the one system on a coach where use is maintenance and disuse is damage, and almost nobody treats it that way.

What sitting actually does

Fuel varnishes. Gasoline degrades. In a carburetted generator, the fuel left in the bowl and passages oxidises into a varnish that blocks the small passages first. Those passages are the idle and low speed circuits, which is why a neglected generator frequently cranks and runs badly rather than not running at all.

Timeline: noticeable at three to six months, problematic at a year, requiring disassembly at two.

Seals and gaskets dry. Rubber and cork components in a stationary engine dry out and shrink. Then when it does run, it leaks.

Carbon builds from light load. This is the counterintuitive one. A generator run for twenty minutes with no load does more harm than good. It never reaches operating temperature, it runs rich, and it deposits carbon on valves, rings and the exhaust. Repeated short no load runs are worse than not running it at all.

Brushes and slip rings corrode. In the generator end rather than the engine, contact surfaces oxidise when idle, which shows up as no output or unstable output on a generator that otherwise runs fine.

Batteries discharge. The generator start battery, which is frequently neglected relative to the house bank.

The schedule that prevents all of it

Two hours, monthly, at a minimum of half rated load.

Every element of that matters:

Two hours. Long enough to reach and hold operating temperature, burn off moisture, and circulate oil properly. Twenty minutes does not.

Monthly. Frequently enough that fuel does not sit long enough to varnish meaningfully.

Half load minimum. This is the part people skip and it is the most important. Load is what makes the engine work, reach temperature and burn cleanly. On an RV that means running the air conditioning, the water heater on electric, and whatever else you have, deliberately.

Running a generator with no load monthly for two hours is close to worthless. Running it under real load for two hours monthly is genuinely all the maintenance most units need beyond oil changes.

What neglect costs

At our posted rates, mechanical and electrical at $260 per hour.

• Generator maintenance service: $250 to $1,500 at 1 to 6 labor hours
• Generator repair and overhaul: $750 to $9,500 at 4 to 40 labor hours
• Generator installation and replacement: $1,500 to $12,000 at 8 to 50 labor hours

A carburettor cleaned before the varnish hardens sits at the bottom of the repair range. A generator that has sat for four years, needs the fuel system disassembled, has carbon fouling and has corroded contacts, sits well up it. A unit beyond economic repair becomes a replacement.

The pattern is the same as everything else in this trade: the maintenance figure and the repair figure differ by an order of magnitude.

The stored coach problem

A coach in long term storage is where this goes wrong most, because monthly exercising requires someone going to the storage yard monthly.

Realistic options:

Do it. An hour of your time, twelve times a year. Best outcome.

Fuel stabiliser and run it dry. Second best. Stabiliser slows varnish formation, and running the carburettor dry before storage means there is much less fuel sitting in it. Not as good as exercising, considerably better than nothing.

Have someone else do it. Some storage facilities offer it. Verify they run it under load, because most do not.

Accept the repair. A legitimate choice if the coach is stored for a year and you would rather budget $750 to $9,500 than make twelve trips. Just make it a decision rather than an accident.

What we do and do not do

We service, repair, overhaul and install generators. That is genuine mechanical work on RV house systems and it is squarely in scope at our $260 per hour rate.

What we do not do is engine or drivetrain work on the vehicle itself, and on commercial and fleet vehicles we do body, paint, structural and equipment installation only.

An RV generator is a house system, not a chassis system, which is why it sits on our side of that line.

The diagnostic that saves money

If a generator is not starting, do not have parts thrown at it.

Our diagnostics rate is $285 per hour with a one hour minimum, refundable as a credit against an authorized repair. One hour establishes whether you have a fuel problem, an ignition problem, a compression problem or a generator end problem, and those are four different repairs at four different prices.

Guessing at that sequence is how a $400 carburettor clean becomes $2,000 of replaced components that were fine.