Briggs & Stratton generator code FC_4

High severity — Four LED blinks: the engine failed to start after repeated attempts.

Applies to: Briggs & Stratton Home Generator System standby units with the fault-code LED indicator

Four blinks means the generator tried and failed to get the engine running. It's often the very first fault code a Briggs & Stratton standby owner ever sees — during a scheduled exercise run, or worse, during an actual outage — and it's also the one most often traced back to something simple.

What it means

Four LED blinks: the engine failed to start after repeated attempts.

The fault-detection system doesn't try to diagnose why the engine won't start; it just counts the failed attempts and locks out once there have been enough of them, similar to how a car's computer flags a no-start after a few key turns without knowing the exact cause. That makes FC_4 more of an invitation to work through fuel, air, and spark in order than a code that points at one specific part.

Most common causes

No fuel supply reaching the engine
Failed spark plug(s) or ignition failure
Clogged air filter restricting intake air
Old/stale gasoline

What you can check yourself

Verify fuel valve is open and there's adequate fuel supply
Check the air filter and clean or replace if dirty
Inspect spark plug(s) for fouling
Reset the fault system and attempt another start

Fuel supply and carbon monoxide.

Never run or crank-test the generator in a garage, basement, or other enclosed space — exhaust carbon monoxide is odorless and can be fatal within minutes.
If you smell raw gasoline or LP gas while checking the fuel system, stop and let the area ventilate before continuing; both a flooded cylinder and a fuel leak call for caution around ignition sources.

Call a professional when: If fuel, air filter, and spark plugs all check out and it still won't start, have a technician check ignition timing and fuel delivery components.

All codes for this brand

Every Briggs & Stratton generator fault code — full list with what differs between models.

Related codes and symptoms

FC_1 — Low battery voltage, the single most common reason a start attempt fails outright
FC_2 — Low oil pressure, a shutdown that can masquerade as a no-start if it trips during cranking
Generator Won't Start

Sources

Briggs & Stratton Home Generator System Operator's Manual — Fault Detection System

This site is an independent reference and is not affiliated with, endorsed by, or sponsored by any generator manufacturer. It is not a substitute for a licensed electrician or generator technician. Standby and portable generators involve mains-voltage output and, on LP/NG units, a live fuel-gas supply — work on wiring, the transfer switch, or the fuel system should be done or verified by someone qualified to do it. Pages are written with AI assistance from the sources listed on each page and checked against them before publishing.