Old Mariner 5Hp questions

[M1Tommy]

I have an old Mariner outboard. It runs OK.... 'won't expect anything incredible from a 5Hp.

OK, what gas/oil ratio do y'all think this critter should be running? I've been mixing 32:1, just on my own notions, but have never found anything more certain. If I'm running too rich, I figure I'm losing power and fouling my plug (it runs pretty sooty)... but I don't want to run w/out enough oil. I've no paperwork on the motor and can't find out anything about it on the 'net.

Now, here's a doozey.... is this critter water or air cooled? OK, after y'all get back in your chairs..... I see nothing comeing out of the motor when it's operating, like water leaving it as I've always seen from outboards that I know are water-cooled. There is what appears to me to be a water inlet tube or ... what???... just behind the prop... facing forwards... sort of bell/funnel shaped. It leads to a small tube that goes up into the lower unit's teeny shroud, then to parts unknown. All that said, while the cylinder has a shroud, it has a lot of what sure look to me to be cooling fins under it and around it... even the shrouded part. I've run the motor for 15-20 min. at a stretch in the lake. It's a pretty noisy motor, typ. to other air-cooled ones I've been around. But before I take off for a day...way down a creek or across a lake, I want to solve this mystery to my satisfaction.

I know, I could start tearing it.. I mean disassembling it, but would rather not unless need be, as in replacing a water pump-impeller.

How think y'all?

Advice/opinions are appreciated.

Tommy

P.S. Below is a link to a photo of the motor. It's a large photo, my apologies to the dial-up folks! The "intake" or whatever it is doesn't show up well. It's located just behind the tip of the uppermost prop blade. Those openings covered by a little square grating is the motor exhaust, and are very useful for blowing water out of a barrel all over the garage, motorcycle, van and work bench.

http://img.photobucket.com/albums/v2...g?t=1183738422