Thread: Husqvarna 266xp price check?

Originally Posted by McNotty

Up to and including 75cc Husky recommend 50:1, and now recommend 33:1 on saws above 75cc.

It's an environmental recommendation not for any benefit to the saw - although the newest spec synthetic modern oils are very capable of running at 50:1 mixes or even leaner in lightly loaded engines. The bigger issue for me is when you are buying small quantities of oils and using different suppliers (the good old whatever you can get at the time). You won't burn a piston/cylinder or damage a bearing on a 40:1 mix even swapping out the brands of 2-stroke oil you are using randomly. I've even had to use marine two-stroke oil designed for water cooled boat engines at 75:1, in small two-stroke engines when in the back of the wops and we ran out of the normal stuff (much bigger job than lead to believe as per normal). Not ideal, but no damage to the little pumps and they are still in use today a couple of years later.

I have a lot of Chinese gear here, blower/mister units etc and they all advise 25:1 in the user manuals that come with them. I've been told that is due to often they do not have oil designed to be used as part of a 2stroke mixed fuel so are effectively using 4-stroke oil in fuel - I just use my normal 2-stroke oil at 40:1 in them and haven't had any issues yet.

The bigger engines revving slower can produce more load on contact points with lower airflow through the engine, so it kind of makes sense to me on the 33:1 on larger engines although Stihl recommend 50:1 on everything.