Thread: which 50-60cc Stihl chainsaw

Originally Posted by woods223

This thread has gotten off track drop OP but getting fuelil mix right isn’t difficult. Have used this formula since 1976. Same formula as taught at trade school in ‘79.
Take number of litres of fuel, multiply by 1000, divide this figure by your mix ratio and this gives you the amount in mls ( millilitres ) to add. eg. 50:1 mix.
5 litres fuel x 1000 = 5000, divide this by 50 = 100 mls oil to add.
Works for any ratio, has done all these years and never had an engine issue due to fuel mix.
I work in the trade and in the case of suspected engine seizure the first thing we do is carry out a fuel burn comparison test: straight fuel: known fuel mix: fuel mix from engine in question. Quickly shows potential fuel mixing cockup. Move on to other engine checks after that if necessary.
We have forest crews using Stihl oil no problems, two operating 30 saws each plus others using up to 10 or more. Opposition has similar numbers running Husqvarna saws/oil. Haven’t heard of any problems from them. We both get customers who have dipshit moments and straight fuel their gear.

Ha, I've been using that formula for a while having sort of worked it out myself using the phone calculator when I'm out away from mixing charts or have to mix a weird amount for some reason.
Thought I was clever too, didn't realise they used to teach it haha.

Have you noticed the die breakdown in older mixed fuel? By that I mean fuel mixed with either red or blue oil that's left for a long period of time turning a golden shade with a smell of old fuel? I've struck that a couple of times recently with old fuel that's been stored in the back of sheds and then found in the can - what's this then? It leaves an oily stain on a evap test, flames like two stroke but has somewhere along the line dumped it's colour. Odd...

One thing with the burn test I've found is some of the newer synthetic oil types are quite a bit lower in density than the older mineral oils. The burn test can make it look like the mix is quite skinny but is actually mixed to spec. Will still tell you straight off if it's a dipshit moment and straight-gassed but not accurate to tell you the actual mix ratio. I've been sort of looking for a repeatable way to get an accurate volume of oil in a mix, but even in a lab it's not straightforward to get an actual ratio and they need to know what the actual brand and type of oil is for comparison checks (the oil density issue again).