When the Power Goes Out, Will Your Generac Generator Start?
I handle purchasing for a 200-person manufacturing company. In 2020, we installed a Generac Guardian 22kW standby generator after two outages cost us a week of production. Last spring, during a routine storm, the generator failed to start. The culprit? A simple oversight that I've since learned is painfully common.
From the outside, it looks like you just buy a generator, plug it in, and forget about it. The reality is that standby generators require regular attention—and most of the problems I've seen boil down to a few misconceptions.
The Surface Problem: 'Why Won't It Start?'
If you've ever had to Google how to start a Generac generator at 2 a.m. during a blackout, you know the panic. Most startup failures aren't mechanical failures—they're human errors or missing maintenance. Here's what I've seen:
- Panel circuit breaker tripped — the generator's internal breaker or the transfer switch breaker can trip during self-tests, and nobody notices until it's needed.
- Dead battery — the battery charger goes unnoticed until the unit refuses to crank.
- Spark plug issues — fouled or worn plugs cause hard starting or misfiring.
These are all preventable. But most buyers (including me, at first) assume the generator will just work.
What I Didn't Know: The Deep Causes Behind Startup Failures
Misunderstanding the Maintenance Reality
This was true 10 years ago: you could buy a portable generator, store it for years, and it'd probably start. Today's standby units (especially the Generac Guardian series) are computerized, with sensors, battery maintainers, and automatic transfer switches. They need annual exercise cycles, oil changes, and spark plug inspection.
People assume generators don't need much. What they don't see is that internal components degrade even when the unit sits idle—moisture, corrosion, and rodent damage are real.
The 'Spark Plug Tells a Story' Rule
How can you tell if a spark plug is bad? I learned this the hard way. After our 2020 installation, I never looked at the plugs. When the unit wouldn't start, a technician pulled one out and showed me:
- White deposits → running too lean (possible intake leak)
- Black, sooty residue → running rich (clogged air filter)
- Oil-fouled plug → worn rings or valve seals
- Cracked porcelain → physical damage from detonation
In our case, the plug was just old. Two years of standby operation had carboned it up. The fix? A $12 spark plug. (Ugh, I wasted a $200 service call for a $12 part.)
The Panel Circuit Breaker Blind Spot
Another hidden surprise: the panel circuit breaker that connects the generator to the house panel can trip during a brief voltage surge or even during a routine self-test. Most people (including me) never check it. Our technician showed me that the breaker had a tiny 'tripped' indicator that was easy to miss. Resetting it took five seconds. The cost of not checking? Hours of downtime while we waited for help. (Not that I'm bitter.)
What's at Stake If You Ignore These Problems
The immediate cost of a generator that won't start is obvious: no backup power. But there are longer-term consequences I've had to explain to my finance team:
- Damage to sensitive electronics — Without a surge protector, the generator's output (which can fluctuate during startup) can fry PLCs, servers, or HVAC controllers. I lost a $3,000 control board because we hadn't installed one.
- Battery replacement — A dead battery that's left discharged for weeks may need replacement, plus possible damage to the charger.
- Warranty voidance — Generac requires documented annual maintenance. Skip it, and a major repair could be out of pocket.
What Is a Surge Protector Used For? (And Why You Need One on Your Generator)
Per UL 1449 standard, a surge protective device (SPD) clamps voltage transients to safe levels. On a standby generator, I now install a whole-house SPD at the main panel. It's a small investment ($150–$300) compared to the cost of fried electronics. The technician explained that generators can produce voltage spikes when the engine speed adjusts or when large loads cycle on and off. Without SPDs, those spikes travel straight to your equipment. (Thankfully, this is an easy retrofit.)
The Short Solution: What I Changed After That Failure
I don't want to oversell this—the fixes are straightforward once you know what to look for.
- Schedule annual professional maintenance before storm season. A good tech checks spark plugs, battery, breaker, and coolant.
- Learn to do visual checks: Look at spark plug condition every 200 run hours. Check the panel circuit breaker monthly. Run a 5-minute manual test under load once a month.
- Add whole-house surge protection if you don't have it. Ask about a Type 1 or Type 2 SPD compatible with your Generac Guardian transfer switch.
In my opinion, the most overlooked step is simply reading the owner's manual (which, honestly, most of us never do). The Generac manual includes a how to start your Generac generator flow chart that covers battery, breaker, fuel supply, and spark—saving you from panic at midnight.
The industry has changed. What was 'best practice' in 2020 may not apply in 2025. But the fundamentals—check the spark plug, mind the breaker, protect your gear—still hold. A little prevention goes a long way.
