zenoah walbro instructions

PMB RACING ZEN8/ZEN9 SETTINGS

With the Walbro 1048 carb start at 1 1/8 H 1 3/4L
With the Mod 257 carb start at 1 1/8 H and 2 L.

Use good quality oil and mix at approximately 13:1 which will be 300ml of oil to 4 litres of petrol. We recommend in UK to use Shell Advance Racing M oil which is a castor/synthetic oil and will give good engine performance, corrosion resistance and good engine life.
Set the tuned pipe at NO LESS than 350mm from exhaust flange to widest part of cone at first and gradually shorten the length to get best performance after 30 minutes of running the engine. Run the motor on the lake using short bursts of full throttle for one or 2 tanks of fuel. You can then run the motor flat out for a few minutes and then bring it in to the shore at full speed, chopping the throttle at the last minute. Remove the spark plug and check the colour of the plug parts inside the combustion chamber, they should be medium brown. If they are black then the H setting is too much. If they are very light brown to grey then immediately make the H more open.