P47flyer,

On all O.S. Max 4-stroke engines, the rocker arm should be set so that a 0.04mm feeler gauge will fit between it and the valve, and a 0.10 mm feeler gauge will not.

We usually set the valves by rotating the engine until one of the valves is fully open, and set the other one. We turn the engine and repeat the process on the other valve.

You can order the O.S. gauges and tool set from your favorite hobby retailer. Here's the stock number and suggested retail price:

OSMG6334 72200060 GAUGES TOOLS 4-CYCLE US$10.99