On my 4-strokes, I spin them over with the throttle wide open for a second or two using an electric starter and no power to the glow plug. Then I pull the throttle back to just above idle, power up the glow pug and they usually fire right up. Colder weather can make it more difficult of course. For an extra shot of fuel on those days I put my finger over the muffler outlet while spinning the engine. This extra back pressure forces a little more fuel into the carb.

Once you get a good 4-stoke dialed in, they start easily and run very consistent. They're a pleasure to own.