1988 Evinrude 48 SPL Charging Question

[papakevin]

Hello everyone, if you don't mind, I have a question regarding the charging system on my 1988 Evinrude 48 outboard. <br /><br />From the links I read here, I did a test of the battery with my multimeter with the motor off and got a strong 12.43 volts DC. When I put on the muffs, cranked up the outboard, and checked the voltage again, I got the same amount of voltage. It's my understanding the voltage should have jumped up if the charging system was working, right? I'm new to this outboard thing (my old boat had a trolling motor only) so I'm just looking for a little help. <br /><br />One last thing. This motor does not have a tach installed on it. What should I do to install a tach in this boat? Is it an easy process? Any recommendations on type, brand, etc?<br /><br />All help is greatly appreciated. Thank you.

 

[Joe Reeves]

Re: 1988 Evinrude 48 SPL Charging Question

Kevin... You would need a tchometer that operates off of a six (6) pulse alternating charging system (very common tach). If you have a regular OMC control box which has a rubber type electrical plug just under the ignition key, purchase a tachometer that has a plug that will simply plug into that socket.<br /><br />Otherwise, the tachometer will have self explanatory instructions.<br /><br />The charging system is a low ampere AC system on that engine with a (usually 4 wire) rectifier on the starboard (right) side of the engine what converts the AC to DC. Should the battery or a battery charger ever be hooked up backwards, that goof/procedure would destroy the rectifier. You can tests the rectifier as follows.<br /><br />(Small Rectifier Test)<br />(J. Reeves)<br /><br />Remove the rectifier wires from the terminal block. Using a ohm meter, connect the black lead of the ohm meter to the rectifier base (ground), then one by one, connect the red lead of the ohm meter to the yellow, yellow/gray, then the red wire (some rectifiers may also have a fourth yellow/blue wire. If so connect to that also). Now, reverse the ohm meter leads and check those same wires again. You should get a reading in one direction, and none at all in the other direction. <br /><br />Now, connect the black lead of the ohm meter to the red wire. One by one, connect the red lead of the ohm meter to the yellow, yellow/gray, and if present, the yellow/blue wire. Then reverse the leads, checking the wires again. Once more, you should get a reading in one direction and none in the other. <br /><br />Note that the reading obtained from the red rectifier wire will be lower then what is obtained from the other wires. <br /><br />Any deviation from the "Reading", "No Reading" as above indicates a faulty rectifier. Note that a rectifier will not tolerate reverse polarity. Simply touching the battery with the cables in the reverse order or hooking up a battery charger backwards will blow the diodes in the rectifier assy immediately.