The manual recommended 16:1 but that saw was built before modern 2 stroke oil was available.IMHO, 40:1 would be a good place to start with quality brand name oil such as Stihl, Husqvarna, Echo, etc.More will likely foul the plug.

I wouldn't go less than about 32:1 ...........you are much Better to foul a plug than to seize the piston............

40:1 will work perfectly fine in that saw. My frieind has a 10-10 Mac and has been running 40:1 Optimol or Stihl 40:1 oil in it for a few years now in this hot deep south temps and the saw does just fine.

my mac 3200 says to use 40:1

guess im real late on this comment but i have a mcCulloch 10-10 when i took off the air filter cover underneath it says 40:1 its an old saw

Info : I agree with Canguy , 40:1 with premium grade synthetic oil will suffice. I personally use Amsoil Sabre up to 70:1 on 60,s vintage saws without any concerns. But any quality Syn oil will given you great performance and protection for any of these older saws. P.S. If any require a manual check out the Chainsawr Site for a download .aka Ewalk !

I have been using AMSOIL Saber Professional 100% Synthetic 2 Stroke oil for years, mixing it at 100:1, it works awesome, I'm using it in all my 2-cycle garden tool and chain saw--Haven't had a problem yet--burns clean and don't plug the spark arrestor screen.

I highly recommend it---