Petrol Pressure Washer Hard to Start, Losing Pressure or Frozen?

The pull cord fights you, the jet has gone weak, or the washer faces winter in a cold shed. Trapped pressure, stale petrol, a worn nozzle or frost could be to blame.

The Petrol Pressure Washers range at PartsForMachines has 38 engine-driven washers from SIP, V-TUF, Clarke, Sealey and Draper, two of them diesel, from 3.2hp to 13hp.

Why Is My Petrol Pressure Washer So Hard to Pull-Start?

Water pressure trapped in the pump is the first thing to rule out: the cord then has to turn the pump against that pressure and can kick back. Turn the water on and, with the lance pointed somewhere safe, squeeze the trigger to let the pressure go before you pull. Never run the pump without water.

If it needs pull after pull once it has stood for months, suspect stale petrol: it deteriorates in storage and makes starting hard, so drain it and refill with fresh. Prefer no pull cord? A key-start model such as the PLS360 petrol washer (7330375) is an option.

Laying Up for Winter: How Do I Protect the Pump and the Petrol?

Get the water out of the pump before the first frost: water left inside can freeze and permanently damage it. Disconnect and drain the hose, gun and lance, then run a pump protector or antifreeze through the pump until it comes out at the outlet. Store the washer indoors, somewhere dry and frost-free.

Petrol goes stale in storage, so either add a fuel stabiliser to fresh fuel and run the engine for a few minutes so the treated fuel reaches the carburettor, or drain the tank and carburettor. Change the engine oil too. If the washer does freeze, let it thaw completely before you start it.

Lost Pressure: Is the Unloader Valve to Blame?

Sometimes, but rule out the simpler causes first. Start with the nozzle: as it wears, the hole grows and pressure falls, so a jet that has weakened gradually often just needs a new nozzle. A blocked or wrong nozzle cuts pressure too. Then clean the inlet filter, open the tap fully and check the inlet hose for kinks and air leaks.

Still low? A worn or sticking unloader can send water back round the pump instead of to the gun. Worn pump valves or seals also cut pressure, so if the nozzle, filter and supply are fine, have the unloader and pump checked.

Bar, Flow or Pump: What Makes a Petrol Washer Last on a Farm?

Look at the pump and engine first, not just the bar figure. Several of our washers built for farm and contractor work, such as the TP760/190 petrol washer (08925), use a brass-headed crankshaft or triplex pump. SIP claims double the lifespan for its in-line triplex crankshaft pump. Look for low-oil protection too, which helps prevent engine damage.

Then compare flow, not just pressure: the higher the flow, the faster a washer cleans. The DD080 petrol washer gives 15 litres a minute from a triplex pump and a 9hp Honda engine.

What Should I Check Before I Buy?

• your water: litres a minute from the tap, a bowser, or a model that draws from a tank after priming
• flow in litres a minute (divide litres an hour by 60) and the working pressure, not only the maximum
• the pump: axial, crankshaft or triplex, and whether it is brass-headed
• the engine: make, model, low-oil protection, pull or key start
• wheels, frame and hose length for your ground and machines

Browse the Petrol Pressure Washers range, or contact the PartsForMachines team by WhatsApp, telephone or email with what you clean, your water supply and how often you wash.

Product options, delivery options and returns terms are shown on each product page. A 30-day return policy applies to eligible items.

Frequently Asked Questions

Is it bad to leave the engine running when I’m not spraying?

For a short pause, no, but don’t leave it long. With the trigger shut, the water circulates inside the pump and heats up quickly. Makers set limits of about two to five minutes, so switch off for longer breaks.

Will my tap keep up with a high-flow petrol washer?

Check first. Time how long your tap takes to fill a 10-litre bucket, work out litres a minute and compare it with the minimum supply on the rating plate or in the manual. A pump short of water loses pressure and can be damaged.

Can a petrol washer work where there is no tap?

Yes, if it carries its own water. The TORRENT2 mini-bowser washer has a 150-litre tank and uses 13 litres a minute, so a full tank gives about 11 to 12 minutes of spraying. Some models can also draw from a tank once primed.

Petrol or electric for farm and yard work?

Petrol, if there is no power point where you wash or you move between yards: an engine-driven washer needs no mains supply. If you always wash beside a suitable socket, an electric washer saves on fuel and engine servicing.

Can I run a petrol pressure washer in a shed or barn?

No. Engine exhaust contains carbon monoxide, a poisonous gas with no colour or smell. Run the washer outdoors, well away from doors, windows and vents, which can draw the fumes in, and take the hose to the job.

Is a big petrol washer too powerful for cars?

It can be. Draper warns that its 13hp 83819 is unsuitable for domestic vehicles because of the water pressure it produces. For mixed work, choose one with adjustable pressure, such as the 08985 petrol washer, and turn it down for delicate surfaces.

Why does my petrol washer cut out with fuel in the tank?

Check the oil. Some of our washers, such as the PWM2500, shut the engine down automatically when the oil runs low, and a low level can stop it restarting. New machines may arrive without oil, as the PWM1300 does. Check the level on flat ground.

Why won’t the detergent injector draw any chemical?

Check the nozzle first. Detergent is applied at low pressure, and with a high-pressure nozzle fitted the injector may not draw. The PWM2500, for example, injects detergent at low pressure and comes with a detergent nozzle in its set.

Which antifreeze should go through the pump for winter?

A pump protector, or an antifreeze your washer’s maker approves. One maker, for example, allows alcohol-free caravan (RV) antifreeze, so check your manual before using anything else.