Trimmers FAQ

Always refer to your instruction manual under “Replacing Nylon Line”. The three most popular STIHL trimmer heads are the AutoCut®, AutoCut® EasySpool™, and TrimCut™. We also offer a video on winding your trimmer head.

All STIHL gasoline-powered engines can be used with up to a 10% (E10) blend of ethanol in the gasoline/engine oil mix. We also recommend that if a unit will be left unused for more than 30 days that it be stored “dry.” This means emptying the fuel tank and then restarting and letting the unit run until all the fuel is consumed and the engine stops. For maximum performance and engine life expectancy, we also recommend using STIHL Ultra HP 2-cycle engine oil.

Note: STIHL recommends use of fuel with no more than 10% ethanol content. Using fuel with greater than 10% ethanol content may cause damage to your equipment and may void your STIHL warranty.

Only if you plan to “mothball” your lawn trimmer, brushcutter or chainsaw for a longer period—say during the winter months—should you pay a little more attention to the topic of “care.” This will ensure that your equipment, when required, will be ready for action. To get the equipment ready for winter, clean it first. The air filter, the cylinder fins, the spark plug, and the dismantled cutting tool should be checked and cleaned (also see instruction manual). Metal parts should be lightly coated with oil to protect them from rust and corrosion. The spark arresting screen in the muffler should be cleaned or replaced with a new one. The fuel tank should be emptied. Run the engine until the fuel system is dry (WARNING; Do not operate the throttle. Run the equipment only at idle speed until the engine stops). STIHL recommends the use of STIHL MotoMix® fuel which is pre-mixed with STIHL HP Ultra synthetic oil. STIHL MotoMix contains no ethanol and has a storage life of up to two years. STIHL MotoMix can be left in the machine during seasonal storage. For winter storage, a dry and, if possible, dust-free and frost-free place would be ideal. You can save space if you hang the equipment. And remember: standard pump gasoline deteriorates. To avoid problems, only purchase enough fuel that can be used within sixty days unless it is STIHL MotoMix. Please refer to the maintenance schedule which can be found in the instruction manual.

Read more about storing your outdoor power equipment

STIHL does not authorize the use of any interchangeable gearbox attachments on these units.

There are several things you can check. First, make sure that you are using fresh fuel mix (never store or use fuel mix older than 60 days in can or fuel tank). Second, clean spark arrester screen in the muffler. Third, replace fuel filter in fuel tank. Fourth, clean or replace air filter. If none of these work please take the machine to your local authorized servicing STIHL Dealer for evaluation.

Read more about storing your outdoor power equipment

This can occur when the trimmer head is not bumped often enough and it becomes too short for centrifugal force to advance the line. When advancing trimmer line, be sure to do so at wide open throttle.

The model number on the fan housing or starter will only have a C after the model number. The C indicates a comfort feature. On trimmers, that comfort feature is the Easy2Start™. You can also confirm it by looking for the bar code label on the trimmer housing. This label will provide the model number, serial number and model name. The name will have a letter E following the C (e.g. FS 56 C-E).

Always read your product instruction manual. When starting your STIHL trimmer make sure that you have fresh fuel mix of 89 octane or higher and never pull the starter more than 3 times in the choke position. If you have pulled more than that, more than likely it is flooded. Indications of flooding are the strong smell of gasoline or gasoline coming from the muffler. The best thing to do at this point is allow the trimmer to rest for 20 to 30 minutes then attempt starting again. Do not choke the unit, but leave the throttle lock on. If it still will not start, we recommend taking it to your local STIHL Dealer for evaluation.

Read more about storing your outdoor power equipment

Curved shaft trimmers are not authorized for any attachments.

STIHL does not produce a straight shaft trimmer that turns clockwise. Only our curved shaft trimmers do.

Curved shaft trimmers are designed for light duty trimming while straight shaft trimmers are designed for more aggressive trimming and brushcutting. Most models are available in loop handle or bike handle versions.

Please contact your authorized STIHL Dealer for special accessories that may be available for your trimmer.

On homeowner trimmers, it is located on the bar code label on the fan casing. On professional units and brushcutters it is on the bar code label and stamped in the top of the cylinder or main crank case. All current serial numbers will be nine digits long and begin with the numbers 1, 2, 5, 8, or 9.

The carburetor comes from the factory with a standard setting. This setting provides an optimum fuel-air mixture under most operating conditions. With most carburetors, it is only possible to adjust the engine idle speed within fine limits. Quite often adjusting the carburetor will not solve acceleration issues. To find the correct setting for your machine, please refer to your instruction manual. If you do not have a copy of your instruction manual, please go to our product manual webpage where you can download a PDF version.

STIHL Inc. maintains a Stolen Unit Database. If your STIHL product was stolen, first please report it stolen to your local law enforcement agency. Then contact us with your name, address, model number, and serial number. If the unit was registered at the time of purchase, we can have it added to the Stolen Unit Database.

STIHL Inc. does not accept product for repair or refurbishment. Please see your local authorized full-line servicing STIHL Dealer.

Please refer to your instruction manual under the maintenance and repairs heading.

STIHL does not incorporate production dates into our serial numbers.

Generally the minimum is 110 lbs. of compression. However, this will vary by model. Compression readings alone are not enough to determine the condition of the engine. Compression gauges are not always accurate and different engines will provide different results.

The correct gap setting is 0.020".

The most common reason is due to too many attempts trying to start the machine in the choke position. When starting a STIHL trimmer unit, make sure to follow the starting instructions in your instruction manual. The manual provides the proper instruction for starting procedures, but there are many conditions that may affect how the unit starts. A good rule of thumb to follow is to remember that when placing the switch control to the full choke setting, more liquid fuel and less air flow into the combustion chamber in order to create a higher chance for ignition. Pulling the rope more than two to three times in this setting may flood the engine. The operator should move the Master Control Lever™ or choke lever from the full choke setting after three to four pulls even if the engine does not fire. Moving the lever to the next setting, the half choke or part throttle position, will allow more air into the combustion chamber and help resolve the flooding condition.