Re: 1964 johnson electric shift voltage
Gary & Dustin... The following should be of interest to you.<br /><br />(Electramatic Shift)<br /> <br />NOTE: This type lower unit must be filled with OMC "Premium Blend" lube, also known as "Type C". You cannot use "HiVis" lube that the mechanical shift units require.<br /> <br />The main shifting components of the straight Electramatic (Johnson) or Selectric (Evinrude) shift lower unit consists of Electromagnetic Coils, Hubs, and Tension Springs (no solenoids). Note that the forward and reverse hubs and coils are of different designs and will not interchange. Voltage (12 volts) is applied to one of the coils via a cable extending from the powerhead to the lower unit. The energized coil draws the spring, which is attached to one of the gears towards it, causing the spring to tighten around and grabbing one of the hubs which is splinded to the prop shaft, causing the propeller to turn.<br /> <br />Obviously a perfect 12v battery is required to provide the needed voltage, and a operating charging system is required to keep the battery in that condition. However, even if a generator does not exist, the lower unit would shift properly as long as the battery voltage is normal (full 12v) and the shift components are not damaged.<br /> <br />Voltage Check: Check the voltage being applied to the lower unit (engine not running). At the powerhead area, find the cable that leads to the lower unit and slide the insulating sleeves back at the knife connectors. DO NOT disconnect the knife connectors. Connect a volt meter red lead between one of the exposed wire knife connections and the meter black lead to a ground. Turn on the key and move the shift lever/button to whichever wire you're checking. If the voltage is considerably less than 12 volts, the unit will not shift properly and the usual cause of the voltage drop is a faulty shift toggle switch (Johnson) or shift button assy (Evinrude).<br /> <br />Ohm Resistance Check: To check the electomagnetic coils, at the powerhead area, disconnect the knife connectors of the shift wires. Connect the red lead of the ohm meter to one of the wires leading to the lower unit with the black lead going to ground. Do the same with the other shift wire.<br /> <br />The ohm reading of the coils should be identical. The exact ohm reading escapes me at the moment but I believe it should be eight (8) ohms. (Someone jump in here with that information please).<br /> <br />If all the above is as it should be, the usual cause of having the lower unit jump out of gear at the higher rpms is that the hub and/or spring is scored. The cure would be to replace both the hub and spring. My experience has been that simply replacing either the hub or spring is a waste of time and results in a repeat of the problem in a very (VERY) short time span.<br /><br />The hub and spring are expensive items unfortunately. I believe that I do have one each left in my remaining stock and would discount them should you find that this is your problem.
ReevesJ32@aol.com
