In carburetors of garden tools, such as lawnmowers, oily grimes build up in the grooves and nozzles of the carburetor system after a long period of operation. If the machine remains untouched in the Winter season, the volatile fuel would result in the build-up of the less volatile substances in the gasoline. In 2-stroke internal combustion engines, components of the oil mixture are deposited in the carburetor and result in starting problems or insufficient combustion in the engine. Therefore, regular cleaning and maintenance on engine carburetors are required to keep your lawnmower in working order.
How to Clean Lawn Mower Carburetor?
The carburetor must be removed from the engine by a thorough cleaning. To do this, remove the air duct or air filter and the fuel line first. The carburetor can then be detached from the engine block by removing the flange screws.
If the lawnmower does not start, stutter or smoke, a dirty carburetor might be a problem. As a gross motorist, you can solve the problem yourself. This guide explains how to properly clean the carburetor on the petrol lawnmower.
Material requirements and tools
Although the specific structure of a carburetor depends on the lawn mower model, the cleaning operations are usually identical. Lawn mower manufacturers offer repair kits for DIY with all important spare parts, such as seals and O-rings. Please provide the following materials and tools:
- Repair kit for lawn mower carburetors;
- Carburetor cleaner or benzine;
- Compressed air source;
- Vat or large bucket;
- Screwdriver, torque wrench
If the manufacturer of your lawnmower does not offer a repair kit, you can purchase the necessary spare parts, such as sealing rings, from the nearest hardware store.
Step by step Cleaning Guide
Disconnect the spark plug cable in advance. For safety purposes, please keep the cable a safe distance from the spark plug. Then remove the air filter and close the fuel tap. On engines without a fuel valve, the fuel line is ideally clamped with a clamp.
How to proceed
- Loosen the fastening screws while the carburetor is still connected to the speed controller;
- Check the positions of the mounting screws in the manual if you have any problems;
- Do not remove the speed control springs until their position has been marked;
- Pour white spirit into a tub;
- Soak the carburetor together with all plastic and metal parts;
- Alternatively, rub or spray the components with a carburetor cleaning agent
While the lawn mower carburetor is soaking, treat the nozzles and lines with compressed air to remove dirty particles. Air filters and spark plugs should also be cleaned on this occasion. Wipe the carburetor and all intact components dry with a clean rag. Please replace damaged or worn parts.
How to Install and adjust the carburetor
Install the clean carburetor and cleaned air filter, reconnect the spark plug cable and spark plug and open the fuel tap. Use the manufacturer’s operating instructions to understand the exact positions of the components. In the last step of the cleaning process, readjust the carburetor. That is how it goes:
- Start the lawn mower;
- Let it run for a few minutes so that the engine warms up;
- Screw-in adjusting screw for regulating the engine speed 1 to 1 1/2 turns;
- Engine speed increases;
- Adjust the setting screw for the idle mixture so that the engine runs smoothly and evenly;
Finally, the engine speed is fine-tuned for the perfect idle speed. Ideally, a tachometer for measuring engine speeds is available for this purpose. The optimal values range from 1200 min-1 for an engine with a cast steel cylinder liner to 1750 min-1 for an engine with an aluminum cylinder.
A carburetor stays clean longer if you start the lawnmower correctly. As soon as the engine has warmed up, the fuel supply should be throttled using the choke. Otherwise, harmful deposits form in the carburetor and other components because not all of the gasoline is burned.
Ultrasonic Cleaning for Lawn Mower Carbs
The normal cleaning methods, such as brushing with brake cleaner or placing them in a gasoline/brake cleaner mixture, might not be able to clean the dirt in the inaccessible places on the carburetor mechanism and in the gasoline lines.
With the ultrasonic cleaning, dirty and oily grimes on the carburetor nozzles can be gently removed. The finest cavitation bubbles clean the carburetor even in hard-to-reach places. It is important for ultrasonic cleaning that the float housing is disassembled. The bath liquid reaches all areas of the carburetor to be cleaned. After ultrasonic cleaning, the carburetor regains its original performance. This is particularly noticeable through the better starting behavior of the corresponding engines.
After cleaning in the ultrasonic bath, the carburetor is rinsed under running tap water and carefully dried with compressed air or a soft cloth. The cleaned carburetor can then be put back together and mounted on the engine.
With this gentle cleaning method, the operating behavior of the engine is significantly improved, time and costs are saved. For a high cleaning volume, ultrasonic cleaning with a big water tank can deal with various sizes and extensive accessories in the single circle.
In addition to cleaning carburetors, the ultrasound cleaner can also be used in the workshop for many other cleaning applications. This includes cleaning spark plugs, injectors, filters, fittings, screws, and many more. The ultrasonic carburetor cleaner is particularly effective because it works in the smallest corner, but the carburetor must first be removed first. If you have no idea about this, you better leave the cleaning to a professional.