Subtopic	Posts		Updated
	Archive through February 28, 2001	5
	Archive through January 12, 2002	4

By Richard L. Johnson on Unrecorded Date: Edit

what is the gasoline/oil mixture for a
50 horse Johnson boat motor?

By Glen H. on Unrecorded Date: Edit

If the motor is from the 70's on up its 50-1. Older than that I don't really know buts probably 30-1.

By George on Unrecorded Date: Edit

Can brutal cold (0-15 degrees) effect the performance of a 2 stroke engine? My Chief seems to be bogging down slightly and I'm wondering if it's just because it's been cold lately.

By Attex Bob on Unrecorded Date: Edit

You bet it will. Screws the air/fuel ratio all up. Cold air is very dense.

By David Keeso (Argomag) on Unrecorded Date: Edit

What about on an old ARGO MAGNUM engine (Kohler Magnum 18 hp.) That might explain why I couldn't seem to get to full throttle the other day when it was -20 celcius, but the day before, I was able to really heat up the engine and I was running wide opened as if the tracks weren't even there.

By Kevin Percy on Unrecorded Date: Edit

My understanding (and I may be wrong) was that cold dry dense air contained more oxygen and would actually give an engine a little more HP if the fuel was there to mix with it. The other extreme is hot moist air.
I found out the hard way that a two stroke has to be warmed up in the cold. If you start it and put it to work witout warming it up the (aluminum) pistons heat up and expand faster than the (cast iron) cylinders and will sieze. I experienced bogging in a JLO twin that was a sign it was getting tight.
Something to watch for too would be carburetor icing. If the air is humid (more likely just below freezing) the moisture in the air can freeze in around the venturi in the carb, and that will mess up the air flow, acting as if you were running with the choke part way closed. If the engine is enclosed it may get some warm air from the engine compartment after the engine has run for a while and the bogging will disappear as the ice melts in the carb.
The Argo Magnum I might suspect was cold enough that all the oil and grease in the engine and drivetrain was so cold and thick that it was making the engine work that much harder. I would think even the tracks would be stiff at that temperature and be that much harder to turn.