Topic: Stihl fuel mixture

[hairyhippy]

I am about to get a second hand Stihl strimmer from my neighbour.

Can anyone tell me how much two stroke oil I need to use with the petrol?

[euronerd]

Hi.

The posts here

http://www.arboristsite.com/archive/index.php/t-1426.html

seem to recommend 40:1. This seems awfully stingy to me. My own 2-stroke (Ryobi) handbook says 20:1 which is about the same proportions I grew up with. It doesn't smoke so I'm sticking with it but it might be worth your digging a bit to make sure 40:1 is OK for your model. And if you find that you can use a non-Stihl oil, get the best you can. I use Shell synthetic scooter oil, which is not to say it's the best, but is vastly over specified for my old Ryobi.

Geoff.

[jennym]

In my college notes it says 50:1 and says one little bottle of Stihl oil for every 5 litres petrol.

[dtw]

Newer engines are designed to use less oil than older ones.
I used to have a very old outboard that worked fine on 50:1
I suppose outboards may use less oil as they are watercooled
and thus run at a lower temperature anyway.

If there is too much oil in the mixture, you may have trouble starting.

[boldielocks]

I tend to put in a bit extra. It doesnt hurt, just as long as you dont under do it.

[ACE]

It was common knowledge in the garden implement trade that some makers led you to believe you needed a weaker mix.


The machines then wore out quicker! Experiment if it smokes it is too much, but will not hurt it, just lessen the oil on the next mix.

[ipt8]

Usually use a 40:1 or 50:1 mix, but you must buy the proper high performance oil sold for chainsaws. It is possible to use 20:1 with lower grade oils but people can usually see where you are working from the clouds of smoke.

You wil know if you have the mix wrong, after running a while the spark plug will be a sort of browny colour. If its white you do not have enough oil, if its black you have too much oil and it is unburnt, which will gunge up the machine. A white spark plug meaning too lean a mixture will seize the engine.

It is important to check the spark plug to see if the machine is tuned correctly.....

[flytrapman]

On some 2 stroke stihl machines the petrol filler cap when removed & upturned holds the amount of oil for a full tank of petrol. Check though as I am not familiar with your model