Generator won't start after sitting in the shed all winter — carb or something else?

Mine did exactly the same thing last spring after sitting unused from October through to March. Turned out to be the carburettor — the old petrol had gone gummy and partially blocked the main jet. Classic winter storage issue.

Few things worth checking before you pull the carb apart:

• Fresh fuel — old petrol goes stale surprisingly quickly, especially E10. Did you drain it before storage?
• Spark plug — pull it out and check the colour. If it's fouled or wet, that'll tell you a lot
• Choke — sounds obvious but worth confirming it's functioning properly
• Air filter — mice love a warm generator shed. Had one nest in mine

If it's fuel-related, a carb clean with some proper carburettor cleaner spray usually sorts it. I used a Honda EU22i on the shepherd's hut build and after one bad winter I started using Briggs & Stratton fuel stabiliser in it before storage — no problems since.

What make and model is yours? Some carbs are dead easy to remove and clean yourself, others are a faff. Also worth knowing — did it crank at all or is it completely dead? If it's not even turning over, you might be looking at a seized engine rather than a fuel issue, which is a different problem entirely.

Interested to hear what others have found with winter storage — do people generally bother draining carbs or just use stabiliser?

Had almost identical grief with my Honda EU22i last spring — sat on the towpath all winter and refused to fire up when I needed it most.

Worth checking a few things before assuming it's just the carb:

• Spark plug — pull it out and inspect; a fouled or corroded plug is often the culprit
• Fuel valve — sometimes these gum up and restrict flow even when the carb itself is clean
• Air filter — damp storage can leave these clogged or mouldy

If you do strip the carb, Berryman B-12 carb cleaner is brilliant for shifting varnish deposits without damaging the jets.

Also, has the oil level been checked? Some generators have a low-oil cutoff that prevents starting — caught me out embarrassingly once.

What model is yours @AlanWard?

Classic old-fuel problem. Few things worth checking beyond the carb:

• Spark plug — pull it out and inspect. After a long sit they often foul or corrode. Chuck a new NGK in, they're pennies
• Air filter — mice love nesting in generators left in sheds. Wouldn't be the first time
• Fuel tap — if it's a petcock style, the rubber diaphragm perishes and blocks flow

My procedure now is run it completely dry before winter storage. Drain the float bowl too if it's got a drain screw. Saves all this grief come spring.

Also worth adding a fuel stabiliser like Briggs & Stratton or Star Tron if you know it's going to sit. Made a massive difference to mine.

If the carb genuinely is gummed up, an ultrasonic cleaner does a far better job than spray carb cleaner alone.

Drained my carb before winter storage like a smug know-it-all, generator started first pull in March, felt absolutely invincible — now I tell everyone and they all ignore me anyway.

Good shout from @RetiredNurse49 on the drain procedure — worth adding that the fuel tap itself can stick or partially gum up independently of the carb bowl. On my cabin genny (a cheap Chinese AVR unit, nothing fancy) I found the tap was letting through barely a trickle even with the needle fully open. Pulled it apart and the rubber diaphragm inside had swollen slightly from sitting in stale E10 petrol all winter. E10's ethanol content is notably worse for rubber seals and plastic fuel components than the old E5 was — worth bearing in mind if your generator is pre-2020. Replaced the tap for about £4 off eBay, ran perfectly after that. If you've cleaned the carb thoroughly and it's still hunting or cutting out under load, suspect the fuel delivery side before throwing more parts at it.