The oil for my new string trimmer & chain saw are both .50, but my old one were .23? can I use the sam oil just in different quantities?
FWIW, I run 32:1 in all of my 2 cycle equipment.
This is what older equipment usually called for. I'm not quite sure what you mean by ".50" and .23". I'm assuming 50:1 and 32:1
I also have some 40+ year old 2 cycle equipment that requires 20:1 because they use bushings instead of needle bearings on the rod. These oldies get their 20:1 so they don't burn up.
Also make sure your oil is rated for two cycle air cooled equipment.
Running 20:1 or 16:1 is no longer required with todays new Premium Oils . Even 32:1 is potentially asking for long term harm with economy 2-stroke oil due to carbon deposits and potential engine overheating issues . Normally 50:1 is more than adequate for even high performance applications. I have small engine units over 50 yrs old that are running very well with original rings and pistons with oil ratio usage of 50 :1 with syntetic amsoil . If you were to choise cheaper economy mineral based 2-stroke oil then purhaps 40:1 may give you added piece of mind .