Maintenance and winterization of the pump: how to extend the lifespan of gasoline and submersible pumps

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Maintenance and winterization of the pump: how to extend the life of gasoline and submersible pumps

A water pump is a machine that differs from most other garden or household machines by one unpleasant feature – most owners don't pay attention to it until it starts having problems. It fits into a garage, a shed, or a well, is occasionally turned on, and from that moment on, it is expected to work reliably. Yet this very approach is the most common cause of premature pump failure, expensive repairs, or complete breakdown in the middle of the season when you need it most.

In this article, we will take a detailed look at how to properly maintain gasoline-powered and submersible electric pumps throughout the year, and especially – how to properly prepare them for winter. Winterization is precisely the phase that most people either underestimate or completely skip, and it is this phase that determines whether you will start the pump in spring with the first pull or whether you will have to carry it to the service.

If you are also interested in how to properly choose a water pump or how to calculate the required lift and power, you will find the answers in other articles from our Knowledge Center: How to choose a water pump: gasoline, submersible or drainage? and Lift and power of the pump: how to calculate what you need for the garden or well.

Why is regular pump maintenance important at all?

The answer is simple when you realize the conditions under which the pump operates. A gasoline pump draws water full of sand, algae fibers, leaves, and mechanical impurities. It circulates it through the impeller chamber, seals, and valves at temperatures where metal expands and contracts. Meanwhile, the engine burns a fuel and air mixture, producing heat, vibrations, and condensation. A submersible pump is constantly immersed in an environment that may contain aggressive substances, sediment, and microorganisms – and we are talking about clean well water, not waste water.

Without regular care, these factors accumulate. The suction filter clogs, the seal hardens, contacts corrode, and the pumping chamber gets clogged. The result is reduced performance, increased fuel or electricity consumption, shortened bearing life, and eventually a failure that is much more expensive than any preventive care. Experience from customer service clearly says: pumps that are regularly maintained work without problems for 10 – 15 years. Those that are neglected fail within 3 – 5 years.

Gasoline pump: maintenance during the season

Gasoline-powered pumps, such as the gasoline water pump BZP-10, are essentially portable combustion engines connected to a pumping unit. This means that when maintaining them, you need to think about two relatively independent parts: the engine and the hydraulic part of the pump. Each has its own requirements and service intervals.

Engine part – oil, filter, spark plug

Engine oil is the first thing to remember. Four-stroke engines in gasoline pumps (for example, the type used in models BZP-20 or BZP-30) have a separate oil circuit and require regular oil changes. The standard interval is every 50 hours of operation or at least once per season. After the first start of a new pump, the first oil change is recommended after 20 hours – at that point, the engine is "broken in" and the oil collects metal shavings from the friction of new parts more quickly. Use oil of class SAE 10W-30 or SAE 30 according to the manufacturer's recommendation, and use engine oil exclusively – never hydraulic or transmission oil.

Air filter should be checked every 25 hours of operation, or sooner if you are pumping in a dusty environment. A paper filter can be cleaned by gently tapping it, a foam filter should be washed in warm water with soap, thoroughly dried, and before installation, lightly lubricated with clean engine oil. A clogged air filter significantly increases fuel consumption and reduces performance – it is one of the cheapest repairs with the biggest effect.

Spark plug should be checked once per season and replaced according to condition. The correct electrode gap is 0.7 – 0.8 mm for most small engines. If the spark plug is covered in black soot or is white and burned out, it tells you something about the fuel mixture – it is either too rich or too lean. A replacement spark plug costs a few euros and should always be kept in reserve directly at the pump.

Fuel system – carburetor and tank

The carburetor is the most sensitive part of a gasoline engine when it comes to long-term storage. Gasoline that sits in the carburetor for several months oxidizes, leaves lacquer deposits, and clogs the jets. The result? The engine starts with great difficulty, runs poorly, and shortly after starting, it stalls or stops. This can be prevented in two ways: either by using a fuel stabilizer (added directly to the tank before storage), or by simply drying out the carburetor – turn off the pump by closing the fuel supply and let the engine run until it naturally stops. This "empties" the carburetor and prevents deposits from forming.

Before each season, I recommend replacing the fuel in the tank with fresh fuel – old gasoline (more than 30 days) has lower calorific value and contains oxidation products that damage the rubber parts of the fuel system. This applies doubly to models with larger tanks, such as, for example, BZP-30 with a 3.6-liter tank, where old gasoline can cause problems even before you get to the actual pumping.

Hydraulic part – pumping chamber and seals

The pumping chamber, impeller (impeller wheel), and mechanical seal (gasket) are parts that wear out gradually. This is noticeable in reduced performance, decreased pressure, or water dripping from the pump body. After each season, it is advisable to check whether the pump shows any signs of water leakage – wet stains or corroded areas are warning signals. The pumping chamber can be disassembled and cleaned of deposits relatively easily on most models, but when it comes to replacing the seals, I recommend leaving it to the service if you do not have experience with mechanical seals.

Gasoline pump: winterization and preparation for storage

Winterizing a gasoline pump is a process that should be carried out thoroughly before the first frosts – ideally when the temperature begins to consistently drop below 5 °C. If you neglect even one step, you may face problems in the spring ranging from an unstartable engine through a cracked pump body to the need to replace the entire pumping unit.

Step by step: how to properly winterize a gasoline pump

1. Drain water from the pump. This is an absolute priority. Water that remains in the pump body or suction hoses can expand the material and crack the pump body or pipe connections during freezing. Disconnect the suction and discharge nozzles, tilt the pump to allow the water to drain out, and then let the pump run for a few seconds to expel any remaining moisture from the chamber walls. Some owners spray compressed air into the chamber – this is an elegant solution if you have a compressor available.

2. Handling fuel. You have two options here. Either completely drain the fuel system (close the valve, let the engine run until it stops, then siphon off the remaining fuel from the tank), or add a fuel stabilizer to the tank and let the engine run for 5–10 minutes to allow the stabilizer to reach the entire fuel system, including the carburetor. The first method is more reliable, but with larger tanks (such as the 3.6 L tank in the BZP-30 model), it can be time-consuming to consume the remaining fuel.

3. Oil change. Changing the oil before winterization, not after it, is essential. Used oil contains acids and metal particles that corrode the inside of the engine during long-term storage. Run the engine to operating temperature (5–10 minutes of operation), turn it off, and drain the warm, flowing oil. Replace it with the prescribed new oil, check the dipstick level, and seal it.

4. Inspection and cleaning of the air filter. Before storage, clean the filter and replace it if it is damaged. Seal or cover the intake and filter with plastic wrap to prevent mice or insects from entering the engine during storage – this may sound like a joke, but it is a fairly common problem in practice.

5. Spark plug and preservative oil. Remove the spark plug, inject a small amount of preservative motor oil (about 5 ml) into the cylinder, pull the starter cord 2–3 times without starting the engine to distribute the oil along the cylinder walls, and then reinstall the spark plug. This protects the cylinder from corrosion during the winter storage.

6. External treatment. Treat the external metal parts with a light corrosion inhibitor (such as WD-40 or a similar product). Pay special attention to the suction and discharge nozzles – install caps or wrap them in foil.

7. Storage. Store the pump in a dry, dust-free, and non-freezing location. The ideal temperature is 5–15 °C. A garage or a dry boiler room are ideal. The pump should be stored horizontally or in the position recommended by the manufacturer – storing it on its side may cause oil to leak through the vent into the air filter.

Submersible pump: maintenance during the season

Submersible pumps are electrical devices that operate fully submerged in water – therefore, they are more enclosed in construction and seem less demanding in terms of maintenance than gasoline-powered ones. However, this does not mean that they can be left completely unattended. Problems with submersible pumps are more insidious precisely because they remain hidden under the surface, where they cannot be directly observed.

A typical example is submersible pump SKM 100 for wells and boreholes – a pump of this type operates in a drilled well several meters below the surface, where mechanical failures, clogging or damage to the electrical insulation are not immediately visible. Regular inspection is therefore all the more important.

What to check with a submersible pump during the season

Electrical insulation and cable. The cable of a submersible pump is constantly in contact with water, is subjected to mechanical stress during assembly and disassembly, and is affected in the long term by minerals in well water. At a minimum, once a year, ideally during disassembly, visually inspect the entire length of the cable for damage to the insulation, cracks or areas worn down by friction against the walls of the borehole. A damaged cable is not only a performance issue, but primarily a safety risk.

Starting device and capacitor. Single-phase submersible pumps use a capacitor to start the motor. The capacitor is the most common reason why the pump makes a humming sound but does not start. The capacitor is a relatively inexpensive part and can be replaced preventively during regular service (every 3 – 5 years) before it fails.

Suction filter and inlet openings. Submersible pumps have inlet openings protected by a mesh or filter. These become clogged over the years with sediment, sand deposits or biofilm. Clogging of the inlet openings means the pump is running "dry" – without sufficient coolant water flow – which quickly damages the motor. Simple cleaning during annual disassembly prevents this failure.

Pressure switch and pressure tank (if installed). If the submersible pump is connected to a household water supply with a pressure tank, the pressure tank must also be checked – the pre-set air pressure in the tank should be 0.2 – 0.5 bar lower than the pump’s switching pressure. More detailed information on calculations can be found in the article Pump discharge and performance: how to calculate what you need for a garden or well.

Submersible pump: winterization and proper storage

Winterizing a submersible pump depends on where and how it is installed. There are two basic scenarios: a pump in a well or borehole that does not freeze, and a pump in surface tanks or seasonal installations, where freezing is a risk.

Submersible pump in a well or borehole – winterization in place

If the well is deep enough and the water is located well below the surface (usually below the freezing depth, which in Slovakia is 80 – 120 cm, and much deeper in boreholes), the pump can remain submerged even during winter. In such a case, it is not necessary to remove it. However, the following must be ensured:

Piping above ground level – if water remains standing in the surface piping, it will freeze and crack the pipes. The discharge piping should either be thermally insulated or have a possibility to drain into the well.
The incoming electrical cable should not be exposed to frost at the point of entry into the well – covering and insulating the cable entry into the shaft is essential.
If the pump is connected via a frequency converter or control unit, these electrical components must be placed in a temperature-controlled space – electronics in a freezing environment fail.

Submersible pump for seasonal use – complete disassembly

If the pump is used for seasonal garden irrigation, pumping from surface tanks or a shallow well, it must be removed and stored before winter. The procedure is as follows:

Turn off the pump and disconnect it from the power supply.
Lift the pump out of the borehole or tank – carefully in the case of a borehole, to avoid damaging the cable or discharge hose.
Let the pump drip dry and then rinse it with clean water – especially the inlet openings. If it pumped water with a high calcium content, remove deposits using a limescale remover.
Dry the pump – let it stand in a warm place for at least 24 – 48 hours to allow water to evaporate from the interior.
Inspect the cable, plug and any connectors – moisture in the cable connection is a breeding ground for corrosion and short circuits.
Store the pump in a dry and cool, but non-freezing space – ideally in the original packaging or wrapped in plastic to prevent dust from entering.

A closer look at the procedure for assembling and disassembling a submersible pump can be found in the article Installation of a submersible pump in a well or borehole: step-by-step guide.

Preparing the pump for starting after winter

As important as winter preparation is, proper preparation of the pump for the season is equally crucial. Mistakes during the spring start-up can undermine even the best winter storage.

Gasoline pump – spring start-up

Before the first start-up after winter, you check: oil level (if you changed it in the fall, it should be clean and sufficient – top up if necessary), air filter (if you covered it with foil, remove it), fuel tank (fill with fresh gasoline), condition of the spark plug, and finally, you check whether all the water has really drained from the pump after the last winter storage. Only then do you try to start the engine.

If the engine won't start, the first step is always to check the fuel and the spark plug. A carburetor after a long period of inactivity may need cleaning – a specialist can do this in half an hour. Never let the engine run dry for more than a few seconds without water in the system, to avoid burning the mechanical seal of the pumping chamber.

The model H-BZP-30 with a power of 9690W and a lift of 95m is a more powerful machine, where service care during the spring start-up is even more important – a larger engine, higher power and greater demands on all components. With powerful pumps, it is also advisable to check the condition of all hose connections and seals on the suction and discharge nozzles, as the higher system pressure will reveal even small leaks that would go unnoticed with a less powerful pump.

Submersible pump – spring start-up

Before re-submerging the pump into the well, you visually inspect the entire cable and all connections. The pump is connected to water at the surface and briefly started – check whether it pumps normally and does not make unusual sounds (squeaking, grinding). Only then do you lower it into the well or borehole to the operating depth.

Looking at common customer problems: it is very common for submersible pumps to fail in spring after winter because the cable was damaged during disassembly in the fall and the customer did not notice it – especially at the bend points. When such a pump is started in spring into water, the short circuit will trip the circuit breaker or cause insulation failure, which is very dangerous in a flooded environment. Always visually inspect the entire length of the cable during disassembly.

Most common maintenance and winter storage errors for pumps

After years of experience with customers, it is possible to distinguish groups of errors that repeat most often:

Wintering a gasoline pump with fuel in the carburetor – the result is clogged nozzles and an engine that won't start in spring. This problem troubles dozens of customers every year and is resolved by the service.
Leaving water in the pump body during freezing – a cracked pump body is an irreparable damage, requiring replacement of the entire pump.
Changing oil in spring instead of in autumn – logically it seems the same, but old oil damages the engine during the entire winter period of inactivity. Oil change in autumn is the correct choice.
Ignoring water quality with a submersible pump – water with high sand content quickly damages the impeller and bearings. If the water source is sandy, the pump must be dimensioned for gritty water or a pre-filter should be installed.
Operating a gasoline pump in an enclosed space – not directly a maintenance issue, but emergency services deal with it every season. Exhaust fumes from the engine are deadly in an enclosed space.
Underestimating the condition of the cable with a submersible pump – a damaged cable is the most common cause of submersible pump failure, which is a relatively cheap fix if caught early.
Not consulting a malfunction with the service – customers sometimes perform inappropriate interventions (e.g., tightening mechanical seals or disassembling the pump chamber without experience) and turn a small problem into a big one. If you are not sure, leave it to the professional.

If you are dealing with specific malfunctions – why the pump is not pumping, losing pressure or overheating – you will find detailed solutions in the article Common pump failures: why it doesn't pump, loses pressure or overheats.

Water quality and its impact on pump lifespan

This is a topic that is often underestimated in discussions about maintenance. The water that the pump circulates directly determines the rate of wear on its internal parts. A simple rule applies: a pump for clean water should only pump clean water – and this is a guarantee for which manufacturers are responsible. If you use it for water containing sand, silt or solid particles, wear is significantly faster.

Hard water with high calcium and magnesium content forms limescale on the internal walls of the pumping chamber and in the valves. It accumulates on the impeller, reduces the cross-section and lowers performance. In combination with long periods of inactivity (e.g., after winter storage without flushing), limescale can even glue moving parts together. The solution is regular flushing of the pump with citric acid or special limescale removers – especially important in areas with hard water.

For more detailed information on which type of pump is suitable for which water, we recommend the article Clean water pump vs. slurry drainage pump: what is the difference and when to use which.

Practical example from practice: wintering a garden system with a gasoline pump

A customer had temporary pumping from a garden pond – a gasoline pump BZP-20 connected via a hose network for 6 irrigation sectors. In the fall, he simply stored the pump in the garage without any preparation. In spring, the pump started, but pumped weakly, the pressure was low and after 10 minutes the engine began to "lose power". Diagnosis: a clogged carburetor with varnish deposits from gasoline, an air filter full of dust, and in addition – a cracked suction nozzle gasket from freezing, because water remained in the hose.

The repair took two days: cleaning the carburetor, replacing the air filter, new suction nozzle gasket. The costs were significantly higher than the price of one hour of careful autumn winter storage. This example is typical and repeatable – and that is exactly why this article is important.

An analogous case with a submersible pump: a customer removed the pump from the well in the fall, threw it wet into the basement where the temperature was close to zero, laid the cable across a sharp edge. In spring – a short circuit in the cable (moisture plus damage), the pump did not work at all. A new pump is a much more expensive expense than 20 minutes of proper drying and cable inspection in the fall.

Service log and maintenance record

A professional approach I recommend, regardless of whether you have one pump or an entire system, is simple maintenance record keeping. A notebook or a table on your phone is enough, where you record: operating hours date, oil change date, air filter change, spark plug condition, winter storage date and spring start-up date. Such a record will provide you with valuable history after 5 years, which service technicians will appreciate when troubleshooting – and will help you not to underestimate any important interval.

Spare parts – what to always have on hand

Experienced users of gasoline pumps always have at least the following in their stock: a spare spark plug, an air filter, oil (a small reserve), a suction basket gasket and a hose nozzle gasket. These parts cost very little, but their absence at the wrong moment (in the middle of a garden season, when pumping a basement after a downpour) can put you in an unpleasant situation.

With submersible pumps, I recommend having a spare capacitor, a supply of cable connectors matching the cable diameter and a set of sealing O-rings for the specific pump model. More detailed information on choosing the right submersible pump and its technical parameters can be found in the article Submersible pump for a well or borehole: what diameter and depth fit which pump.

Most frequently asked questions (FAQ)

Do I have to remove the submersible pump from the well every year for winter?

No, not always. If the well is deep enough and the water level remains well below the freezing level (at least 1 – 1.2 m in Slovakia, much more in deep boreholes), the pump can remain in place throughout the winter. However, it is important to ensure that the surface piping and power cable are not exposed to freezing. If you are unsure about the depth and temperature conditions at a specific location, it is better to lift the pump.

What happens if I forget to drain the water from the gasoline pump before winter?

At freezing temperatures, the water inside the pump body will freeze and expand – the metal will crack or the sealing will deform. A typical result is a cracked cast iron or plastic pump housing, which means the entire pumping unit or the whole pump must be replaced.

Do you have a question about this topic?

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