All my tools smoke now

13 Nov 2008
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United Kingdom
I have a nice selection of petrol tools now so purchased a larger mixing bottle & bigger bottle of two stroke oil.
Oil is Stihl & red in colour, same as before just bigger quantity purchased.

Bottle is shown in attached photo.
All my tools require 40:1 mix
All my tools were running fine.

So I filled the bottle up to the line shown in red with fuel.
I then filled the bottle from that line to the 40:1 line shown by blue arrow.

Today I used 3 different tools and when I Rev the engine ALL show white visable smoke.

I mixed it correctly didnt I ?


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I’ve just called Stihl and asked the same question.
They told me that even though my tools show a required 40:1 mix I should actually be using a 50:1 mix with there red two stroke oil.

40:1 mix has more oil than 50:1 mix so that would explain why these all smoke.

But I’m trying to get my head around if these all show 40:1 on the cap why mix 50:1 ?

Doesn’t the oil actually help with cooling ?

Last thing I want to do is seize these tools up.
Genuine Stihl two stroke mixing oil is a first class product - as is Husqvarna, Oregon etc.
All of these are fine at 50:1 mix and is preferred to minimise pollution.
A 40:1 mix is just fine if you want to leave it that way and weakening of the fuel/air mixture can be ignored.
John :)
Some older & cheap Chinese machines ask for 25:1
Doesn't matter what it says on the machine or manual, 50:1 in everything, using a decent semi (or fully) synthetic two stroke oil.
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Dont want it smoking so i will use whats in the tank & make 50-1 next times.
For DIY use buy stihl motomix or equivalent. Ready mixed fuel that doesn't go stale over winter. Won't gum up your carb. OK, expensive but how much do you use? for my strimmer about 2-3 litres/year.
In your picture the blue line you have marked is actually on the 50:1 ratio
The 40:1 line is actually the lower one of the 2 on the left. So if you have topped it up to the lower line on the right you have actually made a 50:1 mix.
On your next mix fill it to the lower line on the left and see if it improves anything. If it makes it better then good. If it's worse then simply drain and re-mix to your original mark.

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