Generator won't start after sitting in the shed all winter — carb issue?

Almost certainly the carb. Old fuel goes stale and leaves a varnish residue that gums up the jets — classic winter storage problem.

Few things to try before pulling the carb apart:

• Drain the old fuel completely — if it's been sat since October it's already degraded
• Fresh fuel + a shot of Easy Start into the air intake, just to confirm it wants to run
• Carb cleaner spray into the air intake as a quick first test
• If none of that works, pull the carb and give the main jet a soak in cleaner overnight

Had this exact issue with my old Honda EU22i last spring. Turned out the main jet was completely blocked. Took about 40 minutes to strip, clean, and reassemble — totally doable with a basic toolkit and a YouTube video open on your phone.

Also worth checking:

• Spark plug (might be fouled)
• Oil level (some generators won't start if it's low due to the low-oil cutoff sensor)
• Fuel tap is actually open 😅

Going forward, run the carb dry before storage or use a fuel stabiliser like Briggs & Stratton's stuff — makes a massive difference. I now do it religiously every autumn.

What make/model is it? Some carbs are easier to source jets for than others if cleaning doesn't sort it.

@CurrentAffairs96 solid advice — though I'd add that before you go full heart-surgery on the carb, try a squirt of Easy Start directly into the air intake. It's basically generator smelling salts. 🧟

Also worth checking the fuel petcock valve — mine was stuck closed and I spent an embarrassing amount of time convinced I

@PeakCamper @CurrentAffairs96 both right — been there with my old Honda EU20i after one particularly brutal winter.

One thing nobody's mentioned: fresh spark plug. Stale fuel residue coats the electrode and you'll be chasing a carb problem that isn't actually there. Cheap fix first.

Also worth checking the fuel tap — on older generators there's often a separate petcock that degrades internally and restricts flow even when "open." Caused me a 2-hour headache once.

If you do end up pulling the carb, a cheap ultrasonic cleaner (got mine off Amazon for £30) does a brilliant job on those tiny jets — way better than aerosol carb cleaner alone.

If the carb clean doesn't sort it, don't overlook the spark plug — mine was fouled beyond recovery after sitting all winter with stale fuel vapour condensing around it. Pulled it out and it was practically black. A new plug is £3 and ten minutes, worth doing alongside the carb work rather than after.

Also worth checking the fuel petcock hasn't seized — I found mine on my little Chinese-built backup genny had corroded shut. Looked fine externally but nothing was actually reaching the carb at all. Spent a good hour faffing with the carb before I realised. Classic lesson in working through the whole fuel path systematically rather than jumping straight to the complicated bit.

Fuel stabiliser in storage is like sunscreen on a British holiday — you think you won't need it, then you absolutely do.