[Yosemite Sam]

Depending on how much you intend to use the "test stand"... Set 2 4x4s on your work bench, then set the engine on the 4x4s, with each side of the engine on each 4x4. Space the 4x4s so that the lower part of the shroud just fits between them. Then screw 1x2/3s to them, one in the front of the shroud and one on the pto end of the engine, this creates a "box" that the engine can not escape from. The 1x2/3s hold the 4x4s in place AND keep the engine from moving front to back, the bottom of the shroud hangs down between the 4x4s preventing the engine from shifting side to side.

Bolt a Narrow Frame gas tank to the engine, use your boost box, spare battery or jumper cables to spin the S/G and attach a jumper wire to the pos. (from the power source) to the pos. side of the coil. When the engine starts remove the pos. from the S/G.

This works best with 10 and 12 hp engines, the 14 hp engines won't set level because the shroud is bigger, but you can put another piece of 1 by lumber under the pto end of the "test stand" and it levels up nicely. 7 hp engines require a couple of drywall screws driven down through the mounting holes to keep the engine from vibrating from side to side.

Easy peasy, the "test stand" stores in a very small space when not in use and costs practically nothing to make.

DISCLAIMER: I do not run my engines on the "bench" in my shop, as the bench is in an area without adequate ventilation. I normally set the "test stand" on the concrete, just outside the door.