Model Engine Company of America

A typical model engine crankshaft acts as a rotating valve. It has a window or port cut into it and it is timed with the travel of the piston. It also determines the direction the engine will run.

Reverse rotation crankshafts may be available but if they are not or you don't want to spend the money this may solve the problem.

If your engine has a bolt on front housing the running direction of the engine can be reversed without changing the crankshaft.

Reverse rotation crankshafts are usually made in small quantifies with the production of regular crankshafts. Depending on the demand forecast we may have them in stock but if we run out it would be cost prohibitive to set up to make a few.

The technique below allows engines with bolt on front housings to run in reverse by simply rotation the front housing 90 degrees.



Check your crankshaft carefully.

If your crankshaft has a spiral oil groove, do not use the above mentioned method.

The spiral oil groove keeps the fuel/oil from leaking out the front bearing. By reversing the rotation you will be pushing the mixture out the front.

Most later K&B engines use this method to retain the mixture.

Also check the inside of the front housing just behind the front bearing. Sometime there is a spiral groove cut into the housing rather than the crankshaft. This is not very common but you should check.

Also See Crank Rotation


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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