Stihl TS 700 Straight Gas Damage (Field Guide)
If a STIHL TS 700 has been run on straight gasoline, stop it and do not restart it to test the engine. Drainage alone cannot undo damage from missing two-cycle oil. Have the fuel system and engine inspected before use. For prevention, confirm the correct 50:1 mix, inspect the approved cutting wheel, and follow the saw’s manual.
A reliable cut starts before you squeeze the throttle. The TS 700 is a powerful cut-off saw, but a wrong fuel mix can turn a routine job into a costly repair. If you manage several gas tools, keep this saw’s premix clearly labeled and separate from straight gasoline. That simple habit helps prevent a mix-up when work is waiting.
I treat suspected straight-gas use as a stop-work issue, not a carburetor adjustment problem. The safe next step depends on whether the saw was merely filled, started briefly, or run under load. In every case, do not start it again until you have confirmed the situation and, if it ran, arranged an inspection.
What straight-gas damage means on a TS 700
Straight-gas damage is harm caused when a two-stroke engine runs on gasoline without the oil needed for lubrication. The TS 700 is a 98.5 cm³, 5.0 kW two-stroke cut-off saw. Without the specified oil mixed into its fuel, internal parts may wear, score, overheat, or seize.
Gasoline alone does not provide the lubrication this engine needs. The moving piston, cylinder, bearings, and crankshaft depend on oil carried in the fuel mixture. Damage is not guaranteed every time the wrong fuel is added, but running the engine on straight gasoline can cause severe damage.
The machine is designed for compatible abrasive or resin-bonded cutting wheels, not a guide bar and chain. It is not a chainsaw or a wood-felling saw. Before operating, check the operator’s manual and the wheel label for the allowed wheel type, diameter, arbor fit, and speed rating.
What to do if straight gasoline went into the tank
The right response is to keep the saw off and prevent further operation. Do not restart it to hear how it sounds, burn through the fuel, or see whether fresh premix clears the problem. If it was only filled and never started, the engine has not run on that fuel, but the tank still needs to be drained safely.
If it was started or run, stop it as soon as you can do so safely. Let it cool in a safe place, away from flames and other ignition sources. Keep the fuel away from hot parts, and do not drain it near a drain, flame, or other ignition source.
| What happened | What to do next | What not to do |
|---|---|---|
| Straight gasoline added, engine not started | Keep it off; arrange safe tank draining and correct refueling | Do not start it to “mix in” oil |
| Engine started briefly | Stop it; do not restart; contact a qualified STIHL service provider | Do not test it with fresh fuel |
| Engine ran under load or lost power | Stop, let it cool, and request engine inspection | Do not keep cutting or adjust the carburetor |
| Engine will not turn or seems seized | Leave it off and have it assessed | Do not force the starter |
Draining the tank removes contaminated fuel; it does not repair internal wear. A technician may need to check the piston and cylinder for scoring or seizure, inspect fuel delivery and carburetion, and assess compression or cylinder condition. Do not tune the carburetor to hide symptoms that may come from engine damage.
Correct fuel and pre-start checks
Correct fuel means fresh gasoline mixed with the specified two-cycle oil at the ratio required by the manual. For the TS 700, the specified ratio is 50:1 when using STIHL two-cycle engine oil. Confirm the instructions for your specific saw and oil before mixing; do not rely on memory or the label on another tool.
At 50:1, the ratio is 50 parts gasoline to one part oil. For example, that equals 100 mL of oil for 5 L of gasoline. Measure carefully with a suitable container, mix in an approved fuel container, and label it clearly as two-cycle premix.
| Gasoline amount | Two-cycle oil at 50:1 |
|---|---|
| 1 L | 20 mL |
| 5 L | 100 mL |
| 10 L | 200 mL |
Use fresh fuel and follow the manual and fuel-maker directions for storage. Keep premix separate from straight gasoline used in other equipment. A dedicated, clearly marked container reduces confusion when you move between a mower, trimmer, blower, and cut-off saw.
Inspect the machine and wheel
Before starting, check the guard, wheel, flange and arbor fit, fasteners, fuel lines, air filter, and controls. Look for damage or leaks. Use only a wheel approved for the TS 700 and the material being cut. The maximum wheel diameter is 350 mm (14 in), but the manual and wheel label govern what is suitable for your saw and task.
Check that the wheel’s maximum rated speed is not below the saw’s specified spindle speed. Do not use a cracked, damaged, contaminated, or worn-out wheel. A wheel is not sharpened like a chain; replace it if defective or beyond its limits.
The saw’s approximate idle speed is 2,500 rpm. At idle, the wheel should remain stopped. If it spins, fuel leaks, or the engine sounds abnormal, stop and arrange service instead of cutting.
Safe starting and cutting
Safe operation starts with a stable machine, a clear work area, and protective equipment. Wear eye and face protection, hearing protection, gloves, protective clothing, and suitable footwear. Secure the workpiece, move bystanders away, and check for combustibles, dust, ventilation, and fire risks before starting.
Start outdoors on stable ground with the wheel clear of the material. Follow the starting steps in the operator’s manual. Keep a firm two-handed grip and position the guard as directed. Keep the wheel’s plane away from your body and other people.
Use the correct wheel for the material. Make a controlled cut without twisting, forcing, or side-loading the wheel. If cutting concrete or masonry, apply the required silica-dust controls. Where applicable, follow OSHA’s construction silica standard, 29 CFR 1926.1153, along with site rules and the manual.
When finished, use the stop control and wait until the wheel comes to a complete stop. Let the machine cool before refueling, inspection, or cleaning. Keep hot parts away from fuel and dry vegetation.
Field scenarios: choosing the safe response
These examples are practical decision guides, not claims about a particular repair outcome. The key difference is whether the engine ran on straight gasoline. If it did, avoid further starting and get an inspection before returning the saw to service.
The tank was filled, but the saw was not started
Keep the saw off. Have the straight gasoline removed safely, then use fresh premix at the specified ratio. Since the engine did not run on the wrong fuel, it was not operated without lubrication; still, do not start until the fuel mix-up is resolved.
The saw ran, then stopped or lost power
Stop using it and do not restart it with fresh fuel. A loss of power can have more than one cause, so it does not prove straight-gas damage. But if straight gasoline was used, tell the service provider what happened and request checks for piston or cylinder scoring, seizure, fuel delivery, carburetion, and compression or cylinder condition.
The engine turns, but sounds or behaves abnormally
Do not use the starter as a diagnostic tool after suspected straight-gas operation. Unusual sound, hard starting, power loss, or a locked engine warrants service. Draining and refilling may correct the fuel in the tank, but it cannot establish that the engine is undamaged.
Maintenance and seasonal storage
Routine care helps keep the TS 700 ready, but it cannot reverse damage from running without oil. Follow the operator’s manual for air-filter care, cooling-air passages, guard cleaning, service intervals, and repair procedures. Do not invent torque values or change engine settings without the correct service data.
For seasonal storage, use correctly mixed fuel and follow the manual and fuel-maker directions for storage or fuel-system preparation. Store the cooled saw upright in a dry, secure, well-ventilated place, away from ignition sources and unauthorized users. Remove or protect the wheel as the manual directs, and store fuel and spare wheels safely.
Before the next job, check the fuel label and wheel condition again. If you suspect straight-gas operation, do not return the saw to service until a qualified STIHL service provider has inspected it. A clean fuel container and a clear stop-use rule are cheaper than guessing at internal damage.
Frequently asked questions
These answers cover the most common decisions after a fuel mix-up or before using the saw. The manual for the specific machine and the wheel label remain the final references for operation and compatibility.
Can straight gasoline damage a STIHL TS 700?
Yes. The TS 700 is a two-stroke engine that needs oil in its fuel for lubrication. Running it on straight gasoline can damage internal parts, including the piston and cylinder.
What should I do if I added straight gas but did not start the saw?
Keep it off and have the tank drained safely. Do not start it to mix oil into the gasoline. Refill only with fresh fuel mixed at the specified ratio.
Can I restart the saw after draining the straight gasoline?
Not if the engine ran on that fuel. Draining does not show whether internal damage occurred. Arrange an inspection before restarting it.
Will fresh premix repair straight-gas damage?
No. Correct premix provides the required fuel and oil for future operation, but it cannot undo scoring, wear, or seizure that may already have occurred.
What is the TS 700 fuel mix ratio?
The specified ratio is 50:1 when using STIHL two-cycle engine oil. Confirm the manual and oil directions for your exact machine and product.
How much oil goes into 5 liters of gasoline at 50:1?
Use 100 mL of oil for 5 L of gasoline. Measure accurately and mix in an approved, clearly labeled fuel container.
What signs can indicate damage after straight-gas use?
Power loss, abnormal sound, difficult starting, or an engine that will not turn can be warning signs, but they do not identify the cause on their own. Stop and request a qualified inspection.
Can I sharpen the TS 700 cutting wheel?
No. Do not sharpen a cut-off wheel like a chain. Inspect it for damage, wear, contamination, and the correct speed rating; replace it if defective or outside its limits.
Can I fit a guide bar and chain to the TS 700?
No. The TS 700 is a cut-off saw for compatible wheels, not a chainsaw for wood cutting or felling.
What is the maximum wheel diameter?
The listed maximum is 350 mm (14 in). Check the specific saw manual and wheel label for approved type, fit, and speed rating before use.
(This article was written by one of our staff writers, Harrison Croft. Visit our Meet the Team page.)
