Model Engine Company of America
Which Way Does the Back Cover Go On?

First off the screw bosses should line up with the crankcase.

NOT LIKE THIS PICTURE.

Usually the top of the back cover will be flat to clear the piston skirt at the bottom of the stroke.

Sometimes there is an additional relief to allow an increased passage for the air/fuel mixture to pass up the bypass.

 
It is rare but I have seen back covers with no flat for the piston skirt, but a relief for the bypass flow. Check the screw bosses if you're not sure.

The above information is provided as a guide. Since MECOA/K&B has no way of determining the ability of the individual using and understanding this information, we assume absolutely NO RESPONSIBILITY for any damage to person or property from the use of this information.
 

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