Check to see if the drain tube on the pony is plugged. If they sit for years or are poorly maintained it will sludge/plug up. I usually poke a long wire up there to free it all up.
Pony takes 1 quart and should be serviced often as they don't have a filter and since it only holds a quart it's cheap insurance.
Jordan
Here is a post that has other capacities http://www.acmoc.org/bb/showthread.php?8316-D2-Oil-capacity