STIHL MS 250 manual Checking Chain Tension Fuel

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Checking Chain Tension Fuel

unit with incorrect idle adjustment. At correct idle speed, the cutting tool should not move.

143BA007 KN

NShut off the engine.

NWear work gloves to protect your hands.

NThe chain must fit snugly against the underside of the bar and it must still be possible to pull the chain along the bar by hand.

NIf necessary, retension the chain.

A new chain has to be retensioned more often than one that has been in use for some time.

NCheck chain tension frequently – see chapter on "Operating Instructions".

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This engine is certified to operate on unleaded gasoline and the STIHL two- stroke engine oil at a mix ratio of 50:1.

Your engine requires a mixture of high- quality gasoline and two-stroke air cooled engine oil.

Use mid-grade unleaded gasoline with a minimum octane rating of 89 ((R+M)/2) and no more than 10% ethanol content.

Fuel with a lower octane rating may increase engine temperatures. This, in turn, increases the risk of piston seizure and damage to the engine.

The chemical composition of the fuel is also important. Some fuel additives not only detrimentally affect elastomers (carburetor diaphragms, oil seals, fuel lines, etc.), but magnesium castings and catalytic converters as well. This could cause running problems or even damage the engine. For this reason STIHL recommends that you use only high-quality unleaded gasoline!

Gasoline with an ethanol content of more than 10% can cause running problems and major damage in engines and should not be used.

The ethanol content in gasoline affects engine running speed – it may be necessary to readjust the carburetor if you use fuels with various ethanol contents.

WARNING

To reduce the risk of personal injury from loss of control and/or contact with the running cutting tool, do not use your

If your power tool shows an incorrect idle adjustment, have your STIHL dealer check your power tool and make proper adjustments and repairs.

The idle speed and maximum speed of the engine change if you switch from a fuel with a certain ethanol content to another fuel with a much higher or lower ethanol content.

This problem can be avoided by always using fuel with the same ethanol content.

Use only STIHL two-stroke engine oil or equivalent high-quality two-stroke engine oils that are designed for use only in air cooled two-cycle engines.

We recommend STIHL HP Ultra 2-Cycle Engine Oil since it is specially formulated for use in STIHL engines.

Do not use BIA or TCW rated (two- stroke water cooled) mix oils or other mix oils that state they are for use in both water cooled and air cooled engines (e.g., outboard motors, snowmobiles, chain saws, mopeds, etc.).

WARNING

Take care when handling gasoline. Avoid direct contact with the skin and avoid inhaling fuel vapor. When filling at the pump, first remove the container from your vehicle and place the container on the ground before filling. To reduce the risk of sparks from static discharge and resulting fire and/or explosion, do not fill fuel containers that are sitting in or on a vehicle or trailer.

MS 250