How to tell 2 stroke from petrol

[Sinjun]

I recently bought a little used Stihl MS 250 chainsaw on Ebay. I was surprised to find that the seller despatched it with some fuel left in the tank. More worryingly, it doesn't look like the red 2 stroke mixture I am used to - fairly colourless though possibly a little darker than petrol. I emptied it an replaced it with 2 stroke but cannot get the chainsaw to start - so I am worried now that the engine had been damaged by being used with straight petrol. I've saved the fuel I found in the tank. Does anyone know how to ascertain whether this is indeed petrol or the proper 2 stroke mixture?

[treequip]

What was in the tank is pretty irrelevant, take the exhaust off and inspect the piston OR if it was sold as working put the fuel it came with back in and send it back

[Tyz05]

What was in the tank is pretty irrelevant, take the exhaust off and inspect the piston OR if it was sold as working put the fuel it came with back in and send it back

 

Ditto.

[swinny]

You need to remove the exhaust to check that the piston is not damaged etc as this would happen if no 2 stroke was in the fuel as no lubrication.

 

Some chainsaw owners out there will not use stihl 2 stroke oil, so colour may vary if other oil is used.

 

I hope the saw is ok for you and you have just possibly flooded it etc

[Ironbark]

Agree that testing may be pointless now, but you could try putting a few drops of the mix on blotting paper. As the fuel evaporates it should leave the lubricating oil on the paper.

[GardenKit]

What was in the tank is pretty irrelevant, take the exhaust off and inspect the piston OR if it was sold as working put the fuel it came with back in and send it back

I agree.

Sold as working.... Not working. Dont try to get it working, it will cost money. Send it back.

[spudulike]

The darker fuel is usually where the petrol has destroyed the properties of the two stroke oil. Red mix will go the colour of whiskey when it is old.

 

As others have said, pull the exhaust off and look at the front of the piston, it should be a nice smooth and wet fuel covered grey colour with the rings nice and shiney, any vertical scores and the ring having similar scores and you have purchased a dud:thumbdown:

[predator]

The darker fuel is usually where the petrol has destroyed the properties of the two stroke oil. Red mix will go the colour of whiskey when it is old.

 

As others have said, pull the exhaust off and look at the front of the piston, it should be a nice smooth and wet fuel covered grey colour with the rings nice and shiney, any vertical scores and the ring having similar scores and you have purchased a dud:thumbdown:

 

GOOD POINT I NEVER KNEW THAT THANKS

[Sinjun]

Thanks all for your replies - much appreciated. I'm going to send the chainsaw back because it just won't start. But I've taken a couple of photos of the piston and cylinder. There are some longitudinal marks in the cylinder and I'd be interested in your opinions as to whether there is damage.

[swinny]

time to send it back i'm afraid