Montague

Glad you got it sorted out. And yes, I'd expect a lot of fuel to shoot out of the carb when the engine is running backwards.

Fwiw, most (if not all) 2-strokes can run backwards, they just don't do it very well (because of the port timeings). However, as you discovered, some do it quite well, espeically when new. If you are hand starting, and it keeps running backwards, try flipping the engine backwards, and it will kick and run forwards.

Spaceclam

because the timing is off when running your engine backwards but the carb intake timing needs to be a certain amount of degrees before the piston hits bdc, in theory, you could make a mirror opposite of your crankshaft's timing (have someone mackine it out for you) and your engine would be just as efficient, just as powerful, but running the opposite direction, am i correct?

Montague

Yep, you are exactly right. In fact, many engine companies used to make "reverse timed" crankshafts for use in twin engine planes and so on. For all I know, they are still available. If you do a reverse timed crank, you'd use a pusher prop as well.

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jettstarblue,the props i have been running are a trainer props,three bladed,except the 12X6 wooden prop however the one i cut down to 11X4,still three bladed, is at the bottom of the scale but would work but if were talking about two pladed props the 12X6 is pretty near the top.One reason for the 12X4 props that come with the plane is to keep the speed down so the flyer will get used to the plane,it's slow flying,then i will try others.Thanks again for the chart.

jettstarblue

O.K., just checking, I know I've changed to a smaller pro after breaking one, and without changing the NV, it ran real rich, and was prone to starting backwards.

Jetts

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I'll try it again but if it insists in running backwards i'll try something else.

They make a diesel engine in a 18 wheeler that will also run backwards,not the best but it will run,then you have 13 reverse and one forward gear,LoL ,but there is a downfall to it,the oil pump also turns backwards sucking the oil out of engine parts like crankshaft so you have a "dry" running engine until either you shut it off or it shuts itself off from lack of lubrication.