I use Mercury Quickare and Quickleen in every tank, and nothing but non-ethanol 87 octane gas. 1 oz Quickleen per 5 gallons, 1 oz Quickare per 10 gallons. My 07 Opti runs like new. Bought a case of 1/2 (3 quarts) of each from European Marine (Don), a BBC sponsor. Much, much cheaper bought in bulk.Last edited by RazorCat on April 22nd, 2014, 10:49 am, edited 1 time in total.