with the first set of new style jonsered in the mid 80's, which were the 625 an 670 champ I ran 1 quart of the green bottle to 5 gallons of gas for a ratio of 20:1 ..... fouled a few plugs with out any major internal malfunctions. still use the 625 yet today after a single rering job for repairs internal! the 670 needed a new top end so not worth the $$$$$$. sold it to steve nw for parts at the local GTG last weekend. 20:1 makes for a great bug repellant......