Small Engines (Lawn Mowers, etc.): homelite c5 fuel mixture

Question
I have an homelite c5 s/n1434276. The fuel cap reads 1 pint sae30 to 1 gallon of fuel. Can I use synthetic oil? What ratio do you suggest?

Answer
WOW!  That's one old saw.

Based on the age I would not use synthetic oil.  I would try to find some Homelite mix oil and mix it 20:1 or 32:1.  Those old saws actually called for 16:1 but there are lots of articles on how the oil has improved over the years (decades) so you can run a leaner oil/fuel mix.  

It can be a personal preference as some articles say today's 50:1 oils are suitable but based on all the conjecture I prefer a richer oil mix as this will better lube the engine and help with cooling.  However, a rich mix produces more smoke, more carbon deposits and spark plug foul more often.   It's a trade-off but the richer oil will reduce metal engine wear.

It's up to you if you want to run a richer or leaner mix but I would stick to regular, not synthetic, oil mix.

Eric