Generator won't start after sitting unused all winter — carb issue or something else?

Same thing happened to me last March — pulled out my old Honda EU20i after it sat untouched in the boat's engine bay from October through to spring, and it turned over like a asthmatic cat trying to cough up a hairball. Wouldn't fire for love nor money.

Nine times out of ten on a carb-fed generator that's been sitting, the culprit is stale petrol gumming up the jets. Modern E10 fuel goes off alarmingly fast — we're talking weeks, not months. That little float bowl turns into something resembling toffee sauce by February.

My fix (after much swearing):

1. Drain the float bowl completely — there's usually a small screw at the bottom
2. Fresh fuel in, fresh fuel only
3. Spray a tiny bit of carb cleaner into the air intake before cranking
4. Check the spark plug — if it's dark and crusty, just swap it, they're pennies

If it still won't bite after all that, it could be the primer bulb cracked or the choke butterfly not seating properly.

The real lesson I took away from this whole saga was: either run the generator dry before winter storage, or use a fuel stabiliser like Sta-bil. My Victron setup on the motorhome handles most things, but when I genuinely need the generator as emergency backup, I need it to actually work — revolutionary concept, I know.

What generator are you running? Inverter type or the older open-frame stuff? Makes a difference in where to look first.

@BoxerCamper almost certainly the carburettor float bowl — old ethanol-blended fuel goes gummy over winter and gums up the main jet something chronic. Worth draining the bowl completely first (there's usually a brass drain screw underneath) before assuming anything worse.

One question though — when you say "turned over," do you mean:

• The pull cord engages and the engine cranks but won't fire, or
• The recoil mechanism itself feels sluggish/stiff?

Because those point to completely different root causes. The former is almost certainly fuel/carb related. The latter could be a lubrication issue or even hydrolocking if any moisture got in.

On my van build I now run a fuel stabiliser (Sta-Bil is the one I use) through any generator before winter storage — sorted this problem entirely. Did you drain the carb before storing it?

@BoxerCamper been there with my narrowboat setup — twice, in fact, before I learned my lesson.

The carb gunk is the obvious culprit and @FormerMariner1 is right, but before you crack anything open, check whether the fuel in the tank has gone stale. Petrol degrades surprisingly fast — anything over 30 days with ethanol blends and you're already on borrowed time.

My current routine:

• Run it dry before winter layup, or
• Use Aspen alkylate fuel — pricey but genuinely stable over months

The EU20i carb is serviceable if you're patient, but Honda genuine jets are worth it over pattern parts. Learned that the expensive way.

One thing nobody mentions — check the spark plug too. A fouled plug after long storage will mimic a carb problem perfectly and send you down completely the wrong rabbit hole.

@BoxerCamper worth checking the spark plug while you've got it apart anyway — they corrode sitting in damp conditions (boat engine bay especially) and a fouled plug will make a clean carb feel like a carb problem.

Also, if the fuel tap has a vacuum-operated diaphragm (common on Honda EU series), those membranes perish over winter and you'll get no fuel flow regardless of carb condition. Easy to overlook.

For prevention going forward: Aspen alkylate fuel. No ethanol, stores virtually indefinitely without gumming. I switched my EU22i over to it two seasons ago and haven't had a single cold-start issue since. Available from most decent tool suppliers — pricier per litre but cheaper than a carb rebuild every spring.

@BoxerCamper one thing nobody's mentioned yet — fuel stabiliser like Sta-Bil before you store it. Massively reduces the gumming issue @FormerMariner1 described.

Also worth checking:

• Air filter — mice absolutely love nesting in stored generators, I've found shredded material blocking mine completely
• Oil level — some Hondas have a low-oil shutoff that prevents starting even on a fresh pull
• Choke position — sounds obvious but cold starts need full choke, easy to forget after months away from it

My EU22i lives in my garden office outbuilding and I now run it for 20 mins every 6-8 weeks through winter just to keep everything circulating. Bit of a faff but saves this exact headache.

If it is the carb, a rebuild kit off eBay is about £8 and surprisingly straightforward on the Honda units.