Bought a new zenoah G-26 engine. Mounted it and tried to start it till was blue in face. All it would do is pop through the muffler. Took it back to where I bought it and they sent it in to Horizon. Turns out it was out of time. The timing disc is on a taper on the shaft, and it had slipped.For what this engine cost that seems like a pretty poor setup. They need to put a woodruff key in this so it can't slip. A hard nose down landing and you'll be sending it in again. Just my two cents worth.

The Zenoa G26 and the G23 before that have been around a long time.

There's a lot of people that have used them over the years with no problems.

There may have actually been some other problem?

A good taper will hold the hub in place. The taper has to be clean & the flywheel nut tight. Also it is better to be able to "slip" in a hard stop. That just may prevent a twisted crankshaft....saving some real $$$ Capt,n

I thought there are keys installed? At least the ones I worked on, G62 and GT80. The G26 uses the same mag, different magnet. If you do not prop through both magnets it will pop as stated, read the instruction manual.

All of the Zenoah engines I have worked on had a woodruff key.

The key is just for aliment, A hard prop strike or crash can shear the key.

Milton