Just drained the lower unit on a 4.5HP I got last weekend. Oil was blue green, but no evidence of water and roughly 100ml came out. The refill with Quicksilver gear lube was normal brown gear fluid. 5queries - Is the old green colour normal in some gear fluids? Was the small amount drained out and replaced normal for this size of engine? What year is it; serial no is 9097258? Am mixing at 50:1, like an old '68 650 we had, is this right? Thanks!