Many power tools with petrol engines are pure seasonal workers. Work starts in March, summer is the daily peak season and October marks the beginning of the annual winter rest. Mothballed, the machines are then ideally freshly washed, cleaned and preserved. Despite all this care, it is often the case that the engine has starting problems or an annoying stutter in the spring – even though the machine was running excellently before the winter rest. What is to blame? Roman Mühleck, Product Manager at AS-Motor knows what to look out for in terms of fuel during storage to ensure a smooth start in the spring.

After preparing the machine for hibernation, the first question to ask is where and how to store it over the winter. The expert from the high grass mower specialists recommends a storage place that is dry and not too warm. It is also important that the place is level so that the machine can stand as horizontally as possible.  With two- and three-wheeled devices, it should be ensured that they cannot tip over so that oil and fuel do not leak out.

Ideally, the tank should be completely filled before storage so that as little air and thus humidity as possible remains in the tank. Depending on the outside temperature, the air humidity can condense into water and settle in the tank, which can have a negative effect on the engine start in the spring during initial operation. This is often the fault of a white, sticky substance in the carburetor and fuel filter that forms from the condensation and evaporation of fuel over the winter months. Deposits can also be caused by corrosion.

The standard road fuels comply with the currently valid standards DIN EN 228 for petrol and DIN EN 590 for diesel fuel. They are designed for a typical storage time in the storage tank at the filling station of three to six months under ideal conditions. With an average wintering period of around five months with strong temperature fluctuations in the equipment shed, this minimum shelf life is quickly exceeded.

Through his many years of experience, Roman Mühleck knows that starting problems in the spring occur particularly frequently when using the standard fuel E10.  The reason for this is the increased ethanol content of this fuel type in conjunction with less than ideal storage conditions and a long retention time in the tank. Since ethanol is hydrophilic, i.e. it loves water, E10 absorbs atmospheric moisture better and the water content in the fuel increases. For regular operation in summer this plays only a minor role, but for the winter break this fuel is therefore only suitable to a limited extent. In principle, it should be clarified in advance whether the engine manufacturer has generally approved operation with E10.

For a good start of the season without stuttering, the AS-Motor expert recommends the following fuels for the last tank filling before the winter break:

• Gasoline for appliances (alkylate gasoline): Gasoline for appliances is a special fuel which, due to its chemical composition, is particularly stable to oxidation, i.e. stable to ageing. This fuel is used by various engine manufacturers and vehicle manufacturers as an initial filling fuel in order to bridge any longer storage times that may occur before initial commissioning by the end user.
• Premium fuel (e.g. 99-102 octane) from brand manufacturers: These fuels are equipped with special additive technology that cleans and protects the engine at the same time. This ensures better performance compared to standard fuels. Many users report that they have no starting problems when restarting seasonal vehicles, such as mulching lawn mowers.
• Standard fuels E5 from brand manufacturers are often also equipped with additive technology. Here, too, there is a protection of the fuel system. Therefore, this fuel is also suitable for the winter break under ideal storage conditions.

A comprehensive equipment check before storing machines for the winter kills three birds with one stone. Firstly, the machines are properly cleaned and permanently preserved; secondly, by checking the functions errors are detected. Thirdly, it shows where there is a need for action or repair by a specialist. The main aim is to ensure that the motorized helpers are functional and ready for use the following spring. Occupational safety is also an important factor here. Blades and flails are exposed to constant high stress and wear. At blade speeds of sometimes more than 200 km/h, everything must be in tip-top condition. The equipment check contributes to a machine’s extended service life and increased value retention.

Every check-up begins with the necessary safety precautions. For example, the possibility of an accidental start of the machine must be eliminated before any action can be performed. For this reason, the main plugs must be disconnected on electric mowers. For battery-powered machines, remove the batteries and, if necessary, activate the off switch or remove the safety key. On motorized machines with a rope start, you must remove the spark plug connector. To be on the safe side with ride-on mowers, remove the ignition key and, if possible, disconnect the battery before starting work on the machine. Close fuel taps and tank ventilation. Basically, good ventilation must be ensured and the machine must be standing safely. Guarantee that no ignition sources are nearby and wear cut-resistant gloves.

To clean the body and frame, first sweep away loose dirt, dust, leaves and branches with a hand brush. Stubborn dirt can be removed with a damp cloth and gentle cleaning agent. The expert from AS-Motor points out that decomposing, damp grass and leaves are particularly corrosive to metals and surfaces. Therefore, pay attention to rotten nests in corners and angles of your machine. The bodywork can be cleaned particularly gently and effectively with compressed air. We do not recommend the use of high-pressure cleaners, which degrease sensitive bearings and components. Cleaning additives are often particularly corrosive. Running water from the hose can be used instead. However, please also avoid sensitive and electrical parts and do not direct water jets at bearings.

Bowden cables and their outer shells can be checked while cleaning the bodywork. Chafe marks, kinks, bruises and broken strands impede correct functioning. Further damage can also result if, for example, a clutch does not disengage the transmission properly. For this reason, test the movement of the cables and the end fastenings. It is best to use a silicone lubricant to lubricate the Bowden cables. In contrast to oils and greases, silicone does not resinify, and less dirt sticks to it.

After cleaning, all joints, hinges and operating levers can now be lubricated with a resin-free multifunctional oil. Please note that no lubricant, oil or wax should get on drive or V-belts, pulleys, brake linings or dry clutches.

For proper cleaning, mowers must be set up, folded over or tilted to the side. This is no problem with electric or battery-powered mowers, which can be placed on either side as they have no oil in the engine. For combustion engines, please proceed as follows: Close the fuel tap and the fuel tank vent. If the tank cap leaks, drain the fuel beforehand. After removing the air filter, the mower can be put on its side. Please note that on 4-stroke engines the air filter housing must always be on top when the mower is folded down, i.e. above the crankcase. Otherwise engine oil will run into the air filter housing and contaminate the intake duct and air filter.

Service stands can be used to safely tilt a ride-on mower. These are available from specialist dealers. Otherwise, the machine can be driven on ramps to make it accessible from below. Secure the ride-on mower so it does not roll away or fall over.

Now you can start cleaning the mower deck. Please pay attention to the sharp cutting tools. There is a risk of injury here. It is best to clean mowers and mowing bonnets immediately after the last use, as the grass residue adhering to them will still be damp. Use tools made of wood or plastic for scraping, so as not to unnecessarily damage coated surfaces.

Although the use of a high-pressure cleaner is not recommended, it can make work much easier when cleaning the mowing deck. However, in this case it is essential to observe the following instructions: Only use it to clean the metal or aluminium surfaces on the underside of the mower housing, and do not use any cleaning additives. Avoid the blade bearings, crankshaft and blade clutch when working with the pressure washer and maintain a nozzle distance of 20-30 cm. After a wet wash it is advantageous to run the machine for a short time. Water residues will fly off the moving parts or be displaced by the air stream.