Engines of the Golden Era – Perky

Your “PERKY” motor has been fabricated, assembled and tested by trained factory experts with all‘ parts held to exceedingly close tolerances. It is a precision made product and should be handled and operated as such. The successful performance and satisfaction “PERKY” is capable of giving depends entirely upon strict adherence to the following instructions.


A complete wiring diagram is included with these instructions. Its application to “PERKY” is as follows. The Ground applies to any metal part of the motor, such as either mounting bracket. Connection to the timer is made by connecting a light, flexible wire. to the small screw on the timer arm. Make all connections as short as possible and solder same wherever possible. Keep the high-tension lead that runs from the top connector on the coil to the spark plug, as far away from all other wires and metal parts of the motor as possible. Check all connections thoroughly, making sure that all wires are properly secured, and will not work loose from vibration. Remember, 90% of all motor failures are due to faulty electrical wiring.

After all connections have been made and checked you can test the electrical circuit by the following method. Unscrew the spark plug from the motor and hold the metal part of the plug against the cylinder, being careful not to let your hand touch the high tension end of the plug. Now turn the motor over by hand and if a spark occurs regularly at the plug, your connections are correct.


During the run-in period, we suggest that you use a gas and oil mixture of about three to one. That is three parts gas to one part oil. After the motor is thoroughly broken in you may increase this mixture to four to one. IMPORTANT. Use only regular white gas and #70 S.A.E. oil. The mixture should be thoroughly shaken up before applying to the motor.

The gas mixture on “PERKY” is controlled by varying the amount of air that is mixed with the gas. By moving the throttle lever on the carbureter towards the front of the motor, the gas mixture is leaned out. By moving the throttle lever as far back as it will go all air is shut off from the carburetor, and this position is used to choke the motor in starting. The maximum operating position of the throttle lever is practically all the way forward. This adjustment is not critical. However, you will find one position that operates most satisfactorily, giving maximum R.P.M.

The gas is fed to the carburetor through a small jet. The jet can be taken out to be cleaned by unscrewing it from the carburetor after the tank has been unscrewed. The hole in this jet is only .011″ in dia. and care should be taken not to enlarge it as this will destroy the proper mixture.

There is a small clapper valve in the carburetor, which admits the gas to the crankcase at the proper time. The action of this valve is entirely automatic. It is operated by the alternate compression and suction in the crankcase as the piston moves up and down. The thickness of this valve is only .005” and it has been lapped to the carburetor seat. The valve face is cleaned automatically by the rapid entrance of the gas and except in extreme cases the valve should not be tampered with.


The spark lever is situated at the front of the motor and is used to advance or retard the spark. Moving the lever down as far as it will go puts it in the fully retarded position. Moving it upward advances the spark. When starting the motor, it is advised that you start it in an almost fully retarded position. That is, almost all the way down. After you have made your final gas adjustment, you can move the spark lever up to an advanced position, which will give you the maximum R.P.M.

The timing cam, which opens and closes the points at the proper time. is located on the front of the crankshaft and also acts as the propeller huh. This cam can be taken off to inspect or clean the points. Care should be taken, however, to locate the cam properly on the shaft.

There is a square section on the front of the shaft which registers with the square hole in the timing cam. One corner of the hole in the cam is rounded and one corner of.the square section on the shaft is rounded. These two should be located in the same spot, otherwise, the cam will not slide onto the shaft properly.

Should the points become dirty or fouled, they can be cleaned very easily.

The timing disc should then he thoroughly washed in clear gasoline. The points themselves have been properly adjusted at the factory and should not be tampered with.


The propeller nut is loosened or tightened by inserting the 3/32″ wire furnished with the motor, in the hole of the propeller nut. The propeller should he put on as firmly as possible, otherwise it will loosen up after the motor has run a few minutes. The propeller turns in an anti-clockwise direction when you are facing the motor. If you are left-handed, mount the propeller so that the compression will fall about 45 deg. to the left of the motor. If you are right-handed have the compression fall at top dead center.

Before mounting “PERKY” in your plane, we suggest that you bench run it for at least two hours. This will enable you to become acquainted with its operation and will also give the motor a thorough run in.

If you have a workbench, you can mount the motor to the end of it by four small wood screws. Another method is to mount the motor on a small piece of wood and hold the wood in a bench Vise.


First, make sure that the motor is firmly anchored. Fill the gas tank with the proper mixture and connect the batteries. Retard the spark lever and move the throttle lever forward until the air hole is closed in the carburetor. Now swing the prop over smartly in an anti-
clockwise direction until the motor pops three or four times. Open the throttle about half way and continue turning motor over until it starts. Let it run for a few seconds to get thoroughly warmed up, then slowly move throttle arm forward until the motor runs smoothly. Now move the timer arm upwards until motor attains maximum R.P.M. CAUTION. Do not run the motor at full speed until it has run at least one hour.

If the motor dies out after making all adjustments, you probably have the mixture a bit too lean. If the motor fires heavily, then the mixture is too rich. After starting it a few times you will become acquainted with the proper position for both the throttle and spark controls.


Don’t tighten the spark plug any more than is necessary. You might break the cylinder seal and make it difficult to get the plug out for cleaning.

Don’t use over three volts on the coil. This can be accomplished by using two dry cells or two flashlight cells.

Don’t take the motor apart immediately to see what makes it go. It has been assembled at the factory to stay together. Taking it apart voids the guarantee.

Don’t use anything but flexible insulated wire for making electrical connections.

Don’t fail to check mounting bolts periodically. They have a habit of loosening.