I said that I would take a photo of an Echo for you. Not an Echo chain saw, but a weed wacker. It has been probably the best piece of outdoor equipment I ever bought. Certainly the least trouble. I know I had it in 1989, but I don't know just how long before that. Maybe a year or two earlier. And it has been used hard.
A couple of years ago, it started cranking hard. I took out the plug (only the second one) and it was bad. No replacement. Let me look.... I found the OEM spark plug and decided to clean it up. Back in the tool. Cranked right up.
I have used Optimol for the pre-mix and it has been just magic. Not smoky. Motor has lasted longer than it should. Still cranks and runs well.
You know I think the thing gets better fuel mileage than before. When I first bought it I could fill the tank and by the time I got tired it would be out of fuel. Now I can fill the tank and by the time I get tired it still has lots of fuel left. Imagine that. Best wishes.
Gary (IMR)