Greengear LPG Generator Won’t Start: Troubleshooting & Spares (2026)
Last updated: July 2026
In 30 seconds:
- Most Greengear no-starts come down to five things: switch position, low oil, an empty propane cylinder, a dirty air filter, or a loose spark plug cap.
- The oil sensor stops the engine on purpose when oil runs low. Top up to the upper line and it will start again.
- Light frost on the cylinder or regulator is normal. Heavy frost can starve the engine of propane — swap cylinders.
- Never run the electric starter for more than 5 seconds. Wait 10 seconds between attempts.
- Work through the 7 safe checks below before calling anyone. They take about 10 minutes and cost nothing.
Your Greengear LPG generator won’t start and you’re due on pitch in an hour. This guide walks you through the exact checks Greengear’s own manual recommends, in the safest order, so you can find the fault fast.
The Greengear GE-3000UK, GE-5000UK and GE-7000UK (from £649) are dedicated LPG generators widely used by UK mobile caterers, and almost every no-start is caused by a simple, owner-fixable fault. The standard advice from the manufacturer’s manual is to check the switch, the oil, the propane supply, the air filter and the spark plug — in that order — before involving a dealer.
The honest summary: the biggest mistake owners make is cranking the battery flat chasing a fault that turns out to be low oil or an empty cylinder. The oil sensor is protecting the engine, not failing you. Check the cheap, simple things first.
Safety First: Before You Touch Anything
Close the propane cylinder valve before you inspect anything. Let the engine cool. Work outdoors — exhaust contains carbon monoxide, so a generator should never run inside the van or trailer.
- Never remove the oil sensor probe when refilling oil. Use the filler cap on the opposite side of the carburettor.
- Never clean the generator with water.
- Never turn the key to START while the engine is already running.
- If you smell propane, close the cylinder valve and stop. Leak-test the connections with soapy water before going any further.
If a check below asks for more than a spanner and a spark plug socket, it belongs to a dealer. Fuel-system and internal engine work should stay with a professional.
The 7 Safe First Checks (About 10 Minutes)
These follow the troubleshooting chart in the Greengear manual. Do them in order — each one rules out a common cause before you move to the next.
Step 1: Check the engine switch and key position
Make sure the engine switch or key is at ON, not OFF. Why: it sounds obvious, but a knocked switch is the single most common “fault” — and takes two seconds to rule out.
Step 2: Unplug every appliance from the sockets
Switch off and unplug anything connected to the generator, then try again. Why: the manual is clear that starting with appliances connected can stop the engine firing. Start the generator first, then plug in.
Step 3: Check the engine oil level
Park the generator level, remove the oil filler cap and check the level. Refill to the upper line with SAE 10W-30 if it’s low. Why: the oil sensor automatically stops the engine — and blocks restarting — when oil falls below a set level. The GE-3000UK holds 0.6 litres; the GE-5000UK and GE-7000UK hold 1.1 litres.
Step 4: Check the propane cylinder and valve
Confirm the cylinder valve is fully open and the cylinder isn’t empty. Swap to a known-good cylinder if in doubt. Why: an empty cylinder is listed in the manual’s own no-start chart, and cylinders feel deceptively heavy even when the propane is gone.
Step 5: Push the spark plug cap firmly home
Press the cap down onto the plug until it seats. If it was loose, try starting again. Why: vibration works the cap loose over time. A loose cap means weak or no spark — the engine cranks but never fires.
Step 6: Clean the air filter
Open the filter housing. Wash a foam element in detergent and dry it fully; tap a paper element clean of dust. Why: a clogged filter chokes the engine. Greengear’s schedule says clean every 50 hours and replace the paper element around every 200 hours — weekly traders hit 50 hours faster than they think.
Step 7: Press the ENERKIT primer and try a controlled start
Push the primer button once or twice, then start. On electric-start models, crank for no more than 5 seconds, return the key to ON, wait 10 seconds, and try again. Why: the primer feeds the ENERKIT carburettor for starting, and the 5-second rule protects both the starter motor and your battery.
First-Ever Start? Two Things Catch Everyone Out
The transportation bolt. Every unit ships with a bolt and rubber sleeve locking the engine mounting bracket. Remove it before the first start — running with it fitted can seriously damage the generator.
The crankcase ships dry. There is no oil in a new Greengear out of the box. Fill to the upper level line before the first start attempt — otherwise the oil sensor will refuse to let it run. Our Greengear LPG generator setup guide covers the full first-start routine.
Fault by Fault: What the Symptom Tells You
The engine won’t crank at all (electric start)
Silence or a weak click when you turn the key points to the battery. Check the battery connections — red and black cables tight and corrosion-free. A battery disconnected for storage is a classic after-winter cause.
You can still trade: set the key to ON and use the recoil starter — the pull-cord works independently of the battery.
It cranks but won’t fire
Work through the 7 checks above. If it still won’t fire, remove the spark plug and inspect the electrode. Clean off any contamination and reset the gap to 0.7–0.8 mm. Greengear’s schedule says clean the plug every 200 hours and replace it at 500 hours.
It starts, then stops after a few minutes
Two usual suspects. First, the oil sensor — a marginal oil level lets the engine start, then shuts it down. Top up to the upper line. Second, restricted propane flow from a heavily frosted cylinder or regulator — see the frost section below.
It runs, but there’s no electricity at the sockets
Check the circuit breaker is at ON. If it trips again the moment you connect an appliance, your load is the problem, not the generator. Fridges, pumps and motors surge to 3–5 times their running wattage at startup — a generator sized for the running load alone will trip on the surge. Also check the AC and DC terminals for loose connections.
If the breaker keeps tripping with a sensible load and sound appliances, stop and consult a servicing dealer.
Power output is weak or fading
The manual names worn carbon brushes as the cause of low power. Brushes should be checked around every 500 hours and replaced once worn to 5 mm. Fading output on a cold day, with frost building on the cylinder, is a propane-flow symptom instead — read on.
Frost on the Cylinder or Regulator: Normal or a Problem?
Light frost is normal and the manual says exactly that. As propane vaporises and expands on its way to the engine, it chills the cylinder, hose and regulator — the amount of frost depends on cylinder size, how hard the generator is working, and the weather.
Frost only becomes a fault when it’s heavy enough to slow vaporisation and starve the engine. The signs: performance fades during service, and ice is visibly building on the tank valve, hose or regulator. Two fixes straight from the manual:
- Swap cylinders and let the cold one warm up. Rotate between two cylinders as needed through service.
- Move the cylinder to the handle end of the generator, where warmed air flows out from the engine fan. Never place it in the path of the exhaust outlet.
A bigger cylinder also vaporises propane faster — a 47 kg bottle holds output far better than a small one on a busy winter pitch. Our LPG cylinder sizes guide explains which size suits which setup. And this is why mobile catering runs on propane: it keeps vaporising down to well below freezing, and the Greengear range is rated to operate from −10 °C to +40 °C.
Quick Fault-Finder Table
| Symptom | Most likely cause | Fix |
|---|---|---|
| Won’t crank (electric start) | Flat or disconnected battery | Check connections; use recoil starter to trade today |
| Cranks, won’t fire | Low oil / empty cylinder / loose plug cap | 7 safe checks, in order |
| Starts, then stops | Oil sensor or heavy frost | Top up oil; swap cylinders |
| Runs, no power at socket | Breaker OFF or startup surge | Breaker ON; start unloaded, then connect |
| Breaker keeps tripping | Overload or appliance fault | Reduce load; if it persists, dealer |
| Weak or fading power | Worn carbon brushes / frost | Brushes replaced at 5 mm; manage cylinders |
| Won’t start after storage | Battery disconnected / oil / stale setup | Reconnect battery, check oil, prime and start |
Spares Worth Carrying in the Van
A small spares kit turns most of these faults into a five-minute fix instead of a lost trading day. For the Greengear range we hold these in UK stock:
- Air filter element — replace around every 200 hours; carry one spare.
- Spark plug — NGK type, gapped 0.7–0.8 mm. Cheap insurance.
- Engine oil — SAE 10W-30, enough for a top-up (0.6 L or 1.1 L capacity depending on model).
- Carbon brushes — if your unit is approaching 500 hours.
- Regulator and battery — longer-life items, worth having on order before failure, not after.
Keeping on top of the service schedule prevents most no-starts in the first place — the full intervals are in our Greengear LPG generator maintenance schedule. Worn hoses and regulators have their own replacement rules, covered in our LPG hose and regulator guide.
When to Call the Dealer — and How the Warranty Works
Some jobs are dealer-only. Valve clearances and carburettor work are scheduled at 1,000 hours and belong to a professional. The same goes for a breaker that keeps tripping on a sensible load, no spark after a plug clean and re-gap, or anything inside the fuel system.
Warranty support on Greengear units is straightforward: if the fault is with the unit itself, collection and re-delivery for repair is free. If the problem turns out to be user error — no oil, blocked filter, wrong fuel — the customer covers the cost, or can use a local service centre instead. That’s why the 7 checks above matter: they catch the user-error faults before a wasted claim.
If you’re diagnosing an ageing unit and weighing up repair against replacement, the current range starts with the Greengear GE-3000UK (3 kW, from £649) and steps up through the Greengear GE-5000UK (5 kW, from £949) to the GE-7000UK (7 kW, from £1,249). All three are dedicated LPG — see the full LPG generators range.
Frequently Asked Questions
Why won’t my Greengear generator start after winter storage?
Usually the battery — it should be disconnected for storage, so reconnect it (red cable first, then black). Then check the oil level, open the cylinder valve fully, press the ENERKIT primer once or twice and start. If it was stored without the storage routine, clean the spark plug and air filter too.
What does the oil sensor on a Greengear generator do?
It stops the engine automatically when crankcase oil falls below a set level, and prevents restarting until you top up. Refill to the upper level line with SAE 10W-30 and the generator will start normally. Never remove the sensor probe when refilling — use the filler cap on the opposite side.
Why is there frost on my propane cylinder and regulator?
Frost is a normal side-effect of propane vaporising and expanding as it flows to the engine. It only signals a problem when performance fades at the same time as heavy ice builds up. Swap to a warm cylinder, or sit the cylinder near the generator’s fan outlet — never by the exhaust.
How long can I run the electric starter for?
No more than 5 seconds at a time. Return the key to ON, wait about 10 seconds, then try again. Longer cranking overheats the starter motor and flattens the battery fast. If repeated attempts fail, stop cranking and work through the safe first checks instead.
Can I run a Greengear generator on butane?
No. Greengear generators are dedicated propane machines, and mobile catering runs on propane full stop. Butane stops vaporising below about 2 °C, so it fails outdoors for most of the UK trading year. Propane keeps flowing in winter, and the Greengear range is rated down to −10 °C.
What spark plug gap does a Greengear generator need?
0.7–0.8 mm, on the NGK plug fitted as standard. Clean the electrode around every 200 running hours and replace the plug at about 500 hours. A contaminated or badly gapped plug is one of the most common reasons a generator cranks but refuses to fire.
Why does my generator trip the breaker when I plug an appliance in?
Startup surge. Motors and compressors — fridges especially — draw 3–5 times their running wattage for a moment at switch-on. Start the generator with nothing connected, then plug appliances in one at a time, biggest first. If the breaker still trips on a sensible load, consult a servicing dealer.
What spares should I carry for a Greengear LPG generator?
A spare air filter element, an NGK spark plug gapped to 0.7–0.8 mm, and a litre of SAE 10W-30 oil cover the most common roadside fixes. Add carbon brushes past 500 hours. We hold Greengear spares in UK stock, so replacements are days away, not weeks.