Re: Gas to oil ratio?
It should be 1 pint of Quicksilver, 2-cycle oil per 6 gallons of gas (or 50:1 ratio). Of course, there are alternate oils/labels to choose as long as it's TCW-3 rated. However, you mentioned Mercury, so I mentioned Quicksilver. That's what I run in my Force 40 hp (by Mercury) and previously in my 40 Mercury (circa. 1980).
Check your Mercury 402 manual to be sure. Everyone should have a service manual for their outboard. Also, search this forum. You'll find things like:
http://forums.iboats.com/showthread.php?t=247602
