I bought a stihl BR550 at a estate sale and it looks like it's hardly been used. It didnt come with the manual and ot says 4 mix on it. Nearest I can tell on the stihl website is it's a 4 stroke but there's no place that I can find for motor oil. Does it still require mixed gas? 50:1 mix ratio?

Thanks in advance.

Check this out

https://www.manualslib.com/manual/977167/Stihl-Br-500.html?page=17

Excellent answer,Ken.

Excellent. Thank you.

I've never met a chainsaw that doesn't use a 50:1 mix.

I have 2 that take 16-1! A Remington, and an a Monkey Wards, and another that uses 32 -1.

It's a leaf blower but the 4 stroke (4mix) kind of rattled me.

it;s 50 to 1. It has valves just like any 4 cycle, but it takes mixed gas.

BR 500, 600 700, 800 are all 4 mix
some of the bigger weed eater are also 4 mix.

Thank you for the explanation.

A 4 stroke that needs mixed gas....who knew.

I run 42.6666667 to 1 in everything 2 stroke.
May sound complicated but actually 3 oz oil to 1 gal gas
simplifies it for me. I buy oil by the gal.

You were smart to ask rather than smoke your engine.

Weird. Basically, a 4 stroke with no sump or oil/filter to change, uses the mixed fuel to lube and the other bearings must be sealed?
How does it sound, and power to weight ratio compared to a 2 stroke?

Seems quite. Can't really comment on its weight because I've never had one before

It's sounds fairly similar to other 2 strokes.

The best part about 4 mix is when the motor starts getting weak a simple valve adjustment and you're back to new.

i have a shindiawa,same concept,it works fine,non oxy gas only(mixed 50:1).starts an runs fine every year.weight wise about the same as 2 stroke(so long as your comparing apples to apples)plenty of power,mines a straight shaft that can be converted to a blade,so its a little heavier than a curved shaft flower bender