An HTP power sprayer is two machines bolted together: an engine and a piston pump. Both wear, and they wear in different ways. Most sprayers that fail early were not badly made — they were run hard, put away wet and never flushed.
This is the routine that keeps one working for years.
After every single use
Flush the whole system with clean water. Not just the tank — run clean water through the pump, hose, gun and nozzle until it comes out clear. Agricultural chemicals are corrosive, and residue left sitting overnight attacks seals and valves from the inside.
Clean the suction strainer and nozzle. Thirty seconds each. A partially blocked strainer makes the pump work harder for less output.
Wipe the machine down and check for leaks. A wet patch that appears in the same place each day is a seal telling you it is about to fail.
Check before every start
- Engine oil level on four-stroke units. Running low destroys an engine quickly and is the most expensive mistake on this list.
- Fuel mix ratio on two-stroke units. Mix fresh and mix accurately — guessing the ratio costs you either seizure or heavy carbon.
- Air filter, especially in dusty conditions.
- Hose condition. Look for cracks, soft spots and bulges near the couplings.
- All clamps and couplings for tightness.
Engine oil
Small air-cooled four-stroke engines are usually run on a straight or multigrade oil specified in the manual. Do not assume a grade — check what your engine calls for and use that, because these engines run hotter than a car engine and the wrong oil thins out.
Change the oil after the first few hours on a new machine, then at the interval in the manual. Fresh oil in a new engine carries away the metal particles from bedding in, and skipping that first change shortens the engine's life more than any later service you miss.
The pump: seals, valves and pistons
Piston pumps are built to be rebuilt. The parts that wear are predictable:
- Piston seals and cups — pressure that will not build or that drops steadily under load.
- Suction and delivery valves — pressure that pulses or hammers instead of holding steady.
- O-rings and gaskets — visible weeping at the joints.
- Pressure gauge — often the first thing to fail, and easy to ignore, but you are flying blind without it.
Keep a basic repair kit on hand rather than ordering when something fails mid-season. The relevant items are listed under HTP pump spare parts, and general wear items under spare parts.
Check the pump oil level if your model has a separate pump crankcase. Many people service the engine faithfully and never look at the pump.
Hoses and fittings
A pressure hose that fails does not leak gently — it bursts, and it can injure whoever is holding it. Replace any hose that shows cracking, a bulge, a soft section or exposed reinforcement. Do not repair a high-pressure hose with tape or a sleeve.
Match the hose to the pressure your pump produces. Our spray hose range lists the layer construction and working pressure of each type.
End-of-season storage
This is where most damage happens, quietly, over months.
- Flush the pump and lines thoroughly with clean water, then drain them.
- Drain the fuel tank and run the carburettor dry, or the fuel will gum up over the off season.
- Change the engine oil before storage, not after — used oil is acidic and should not sit in the engine for months.
- Remove the spark plug, put a few drops of oil into the cylinder, pull the cord twice, refit the plug.
- Store somewhere dry, off the ground, covered against dust, with the hose coiled loosely rather than kinked.
Keep a simple log
A page in a notebook with the date, hours run and what you did is enough. It tells you when the next service is due and, if you ever sell the machine, it is worth real money to the buyer. It also tells you whether a part is genuinely faulty or simply due for replacement.
Browse the full spray pump range if you are comparing machines, or ask us which service items suit the model you already own.