If a lawnmower stutters, runs unevenly and smokes, the carburettor setting is usually no longer correct. Fortunately, common petrol mowers are designed in such a way that you can regulate the carburettor yourself. These instructions explain step by step how to set up your lawnmower perfectly.
How can you optimally adjust a lawnmower?
To tune a lawnmower, you should adjust the carburetor by adjusting the speed and fuel quantity adjustment screws until the engine runs smoothly. Additionally, the cutting height can be adjusted and the air filter cleaned to ensure optimal performance.
Adjusting the carburettor – this is how it works in 4 steps
Commercial gasoline-powered lawnmowers are equipped with 2 adjustment screws. A screw with a spring regulates the speed of the engine when idling. Use a second screw to adjust the amount of fuel or the desired mixture. The manufacturer's manual will tell you where the screws are located on your lawnmower model. How to do it right:
- Start the lawnmower and let it run for a few minutes
- Turn in the adjusting screw with spring to increase the engine speed
- Then adjust the fuel adjustment screw so that the engine runs smoothly
- Finally, reverse the increase in engine speed by slightly unscrewing the spring screw
On many lawnmowers, you can only access the carburettor adjustment screws once you have removed the air filter. You should use this opportunity to clean the filter. If deposits get stuck here, the engine will stutter, even though the carburettor is adjusted correctly.
It's not always the carburettor's fault - tips for adjusting the cutting height
Incorrect settings on the carburettor are not always the cause of engine problems on petrol lawnmowers. When you mow a wet lawn, clumps of grass get stuck in the blade bar. The more grass accumulates, the less smoothly the engine runs. Ultimately the engine stops completely because the blades jam. It doesn't have to come to that.
If it is unavoidable to mow the lawn when it is wet, set the cutting height to maximum. There is usually an adjustment lever on each of the four wheels. At the highest possible cutting height, the risk of the knife bar becoming blocked by wet cuttings is demonstrably reduced.
Tip
If you don't achieve the desired result with a new setting on the carburettor, dirt, grease and deposits will cause the engine problem. Remove the carburetor as recommended in the manufacturer's operating instructions. Clean the component with benzine (€9.00 at Amazon) or in an ultrasonic bath, insert it and make the settings explained here.