Should you repair or replace your portable generator?
Updated August 2026
← Every repair-or-replace call
A portable generator that will not start is almost always a $20–60 carburetor cleaning away from running again, not a $500–1,500 replacement. Stale fuel is the villain. Gasoline left in the bowl through a season turns to varnish, plugs the main jet, and leaves you yanking a starter cord in the dark. Add a $10 spark plug, a $50–120 battery on electric-start models, and an $80–200 voltage regulator, and you have covered most of what actually goes wrong. Replace the machine only when the engine is worn: blue smoke, oil disappearing between runs, or hard starting on fresh fuel and a new plug.
The short version
The 50% rule bites early here, because the machine is cheap to begin with. Half of a $600 builder-grade generator is $300, roughly what a small-engine shop charges for a diagnostic, a carburetor service, and a battery, so paying a shop on a low-end unit is a close call the moment the engine looks suspect. Do the carburetor work yourself and the math swings hard the other way: a $20–60 kit, an hour at the bench, and a 10-year-old generator runs like new. Compression tips it to replacement. Blue smoke, oil use between runs, and hard starting on clean fuel mean worn rings and bore, and nobody rebuilds a 200cc engine for less than a new machine costs.
Your situation, decided
| Situation | Verdict | Why |
|---|---|---|
| Will not start after a year of sitting, fuel smells sour | Repair | A $20–60 carburetor kit or cleaning; the engine is fine |
| Starts and runs, but no power at the outlets | Repair | Usually an $80–200 regulator or lost residual magnetism |
| Electric start clicks, pull start works | Repair | A $50–120 battery, the same as any small-engine battery |
| Surging under load with old fuel in the tank | Repair | Clean the carburetor, then run fresh gas with stabilizer |
| Blue smoke, oil consumption, weak compression | Replace | A worn engine costs more to rebuild than to replace |
| Shop quote over $250 on a 10-year-old $600 unit | Replace | Half the price of new on a machine that sits most of the year |
| Engine seized after being run dry of oil | Replace | A seized engine ends it; store and service the next one properly |
What each path costs
Repairs typically run $20–200; a replacement is $500–1,500 installed. A portable generator lasts 10–20 years or roughly 1,000–2,000 run hours with fresh fuel and regular oil changes. Lost compression, not age, is what finally ends it. Price your own number on the home maintenance cost calculator before you commit either way.
The repair-or-replace call is easy when you know the unit's age and service history. OnOtto keeps both, plus the maintenance that delays this decision for years.
Start your home's service log, freeFrequently asked questions
How do I know the carburetor is gummed up?
The pattern is distinctive. The engine has spark and compression, fires briefly on starting fluid, then dies. Or it starts and surges, hunting up and down with no load attached. Drain a little fuel into a clear jar: varnish-colored gas with a sour smell has been sitting too long. Pull the bowl and you will usually find a white or green crust around the main jet. A $20–60 rebuild kit or a complete replacement carburetor, plus an hour of work, fixes it on most single-cylinder engines.
Should I pay a shop to rebuild the carburetor?
Run the numbers before you drop it off. Small-engine shops charge $80–200 for a carburetor service plus a diagnostic fee, and turnaround right after a storm can stretch to weeks. On a $1,200 inverter generator that is easy money. On a $500 unit already 10 years old, you are halfway to new. A complete replacement carburetor for a common engine costs $20–60 online, and fitting it means four bolts and two fuel lines. Weigh the bill against the remaining life in the machine.
How do I keep the carburetor from gumming up again?
Three habits cover it. Treat every tank with fuel stabilizer, or buy ethanol-free gas. Close the fuel valve and let the engine run the bowl dry before storage, which leaves nothing behind to varnish. Then start the unit and run it 20–30 minutes under some load every quarter, which also charges the battery and circulates oil. Change the oil every 50–100 run hours or once a season. Work through the maintenance checklist and set a reminder for how often to run it.
The engine runs but there is no power at the outlets. Now what?
That is the alternator side, and it is usually fixable. Common causes are a failed voltage regulator at $80–200, worn brushes, a tripped breaker on the panel face, or loss of residual magnetism after long storage, which can sometimes be restored with a documented procedure for your model. None of that justifies a new machine unless the stator is shorted. Ignoring the problem carries its own price the night the grid drops. If outages are routine, price a standby unit instead.