The following is a description of a typical electric starter circuit. While the circuit<br />shown is generic by nature, the basic concepts can be used as a starting point in<br />the troubleshooting process for your application. Additional steps needed to<br />troubleshoot and maintain the system are included.<br /><br />SAFETY CONSIDERATIONS BEFORE YOU START TROUBLESHOOTING:<br /><br />Replacement parts should be carefully selected for marine use only, never retrofit an<br />automotive type solenoid for marine use, they are not tested under the same<br />guidelines as their marine counterparts to be explosion proof. Fumes from a leaking<br />fuel line under the motor hood can be ignited by an arcing automotive solenoid.<br />Be extremely careful about causing sparks that may ignite battery gasses. Work only<br />in a well ventilated area. Battery gasses are highly explosive. Inspect the fuel<br />delivery system of the motor carefully BEFORE you start working on the starter<br />circuit. Be sure that there are no fuel leaks anywhere in or around the engine<br />compartment. Keep a fire extinguisher handy just in case.<br /><br />Never 'jump out' or bypass the Neutral Safety Switch...period. Having a motor , even<br />smaller motors, start while in gear can be life threatening. Losing your balance,<br />going overboard and watching a run-away boat can be very scarry, not to mention,<br />it's very dangerous.<br /><br />Additional points to remember. Starter motors draw huge amounts of current. All<br />wiring connections must be clean and tight. Corroded or rusty connections act as<br />points of high resistance to the current flow that the starter needs to function. If you<br />feel a connection and it feels overly hot, that's probably a point of poor connection.<br />Make sure the starter itself is properly grounded through it's mounting bolts. Check<br />that both battery connections are tight ,clean and bright as well, including the<br />battery ground connection. Long cranking times put a lot of strain on the battery,<br />solenoid, starter and wiring. If things start to get overly hot, stop for a bit, let things<br />cool down, grab a cool drink (non-alcoholic !!) and give it a rest, it'll still be there for<br />round two. If you really get into a jamb, post in the appropriate forum for some<br />additional help and ideas.<br /><br /><br />I figure a picture is worth a thousand words with an explanation of how this circuit<br />works. The circuit may look confusing at first, but it's really a simple concept if<br />broken down into it's parts.<br /><br /><br />
<br /><br /><br />The main parts are:<br /><br />12VDC Battery<br />Ignition Fuse<br />Ignition Switch<br />Neutral Safety Switch<br />Starter Solenoid<br />Starter<br /><br />Circuit theory of operation:<br />-----------------------------------------<br />Lets start at the battery and trace the path of the voltage through the starter system<br />with tips along the way.<br /><br />Since this is a negative ground system, the negative side of the battery is ground.<br /><br />The positive side of the battery supplies 12VDC voltage to one side (large post) of<br />the solenoid at Terminal #6.<br /><br />The ignition supply wire is also connected to this large post of the solenoid.<br />The ignition supply wire may be connected directly to the positive battery post in<br />some applications instead of the solenoid terminal #6.<br /><br />Voltage travels through the ignition supply wire, through a fuse and into the ignition<br />switch at terminal #5. The voltage stops at this point since the key is in the OFF<br />position.<br /><br />When the ignition key is turned to the Start position, the voltage leaves the ignition<br />switch on terminal #4 and travels to one side of the Neutral safety switch (red A).<br /><br />The function of the Neutral Safety switch is to insure that the motor is shifted in<br />Neutral before the motor can start. The neutral safety switch is normally an Open<br />Circuit (no voltage can pass through it) until the motor is in neutral gear.<br /><br />When the motor is shifted into Neutral gear, the switch closes allowing voltage to<br />pass through the switch to ( red B) , and then on to terminal #3 of the solenoid. The<br />voltage enters the solenoid at terminal #3 and then out terminal #2 to ground<br />(terminal #1), completing the circuit. When the solenoid gets voltage and ground<br />(terminals #3 and 2 respectively) the solenoid closes. Usually a click can be heard<br />when the solenoid energizes and it's internal contacts close.<br /><br />When the solenoid closes ( is energized), voltage from terminal #6 is passed through<br />the solenoid to terminal #7 and on to terminal #8, the starter. The voltage continues<br />through the starter windings and finally to ground through the starter case itself<br />which is bolted to ground. This completes the circuit and the starter should spin.<br /><br /><br />Troubleshooting and testing the circuit:<br />------------------------------------------------------------<br /><br />Troubleshooting this circuit is really a piece of cake. All you need is a quality DVM<br />Digital Volt-ohm Meter.<br /><br />Lets first start by checking the battery connections:<br />Positive Battery cable connection<br />Negative Battery cable connection<br />Primary battery ground to powerhead- block<br />Starter mounting bolts- ground.<br />These tests are very important. Small amounts of resistance can have a very large<br />impact on the amount of current that the battery can deliver to the starter. If the<br />resistances are too high, the battery won't be able to supply enough current to spin<br />the starter to full RPM.<br /><br />Drop volt testing of the circuit is perhaps an easier and faster way to test for circuit<br />resistances too.<br />The idea here is to identify the points of unwanted resistance and correct them so<br />battery current can flow.<br /><br />Set your DVM to read DC volts.<br />Remove the wire at terminal #2<br /><br />Connect the voltmeter Black test lead to a good ground. The battery Negative post<br />is ideal.<br /><br />Using the Red test lead:<br />Probe terminal #6, you should see 12VDC . If you read zero volts, check for a broken<br />wire between the positive battery clamp and term #6 or a poor<br />connection at positive battery terminal or terminal END at #6.<br /><br />Probe terminal #5, you should see 12VDC . If you have zero volts, check for blown<br />fuse, or broken ignition supply wire between terminals #6 and #5.<br /><br />Probe terminal #4 , turn ignition key to start position. You should see 12VDC. If you<br />have zero volts, replace ignition switch.<br /><br />Probe the ignition switch side of the Neutral Safety Switch (red A) and turn ignition<br />key to start position. You should see 12VDC . If you have zero volts, check for a<br />broken wire between terminal #4 and the red A.<br />Return ignition key to OFF position.<br /><br />Probe the red B terminal. Place motor in Neutral gear and turn ignition key to start<br />position. You should see 12VDC at the red B terminal. If you have zero volts, replace<br />Neutral Safety Switch. Return ignition key to OFF position.<br /><br />Probe terminal #3 . Place motor in Neutral gear and turn ignition key to start position.<br />You should see 12VDC at terminal #3. If you have zero volts, check for broken wire<br />between the red B and terminal #3.<br />Return ignition key to OFF position.<br /><br />To test terminal #2.<br />Probe terminal #2 (post of solenoid), Place motor in Neutral gear and turn ignition<br />key to start position.<br />You should read 12VDC. If you show zero volts, you have an open coil in the<br />solenoid, replace solenoid.<br /><br />The last connection to test is the jumper wire from terminal #2 and #1 (ground<br />connection). To test this jumper wire (it's still disconnected from the solenoid), place<br />Black test probe on the terminal END of #2 and place the RED test probe on battery<br />positive. You should read 12VDC. If you show zero volts, you have either a broken<br />wire between terminal END #2 and terminal #1 OR terminal #1 is corroded and not<br />making good ground contact.<br /><br />Replace the terminal END #2 back on solenoid.<br /><br />Turn ignition key to start position, you should hear solenoid click.<br />If you don't hear the solenoid 'click' after doing the above tests, the coil of the<br />solenoid is probably open, replace solenoid.<br /><br /><br />Starter Test:<br /><br />Place the Black test lead on negative battery POST<br />Place RED test lead on the starter case<br />Turn key to start position<br />Meter should read zero volts<br />If you read a voltage much over .250, you have a ground problem.<br />Check the following:<br />Negative battery cable to powerhead-block ground connection<br />Negative battery terminal connection<br />Starter mounting bolts.<br /><br /><br />Place the RED test lead on the positive battery POST<br />Place the Back test lead on the starters battery connection STUD<br />Turn the key to the start position<br />Meter should read zero volts<br />If you read much over .250 volts you have a bad connection.<br />Check the following:<br />Bad connection at terminal #8<br />Bad connection at terminal #7<br />Bad internal contact points of solenoid<br />Bad connection at terminal #6<br />Bad contact at positive battery cable<br /><br /><br />Please feel free to post your comments and suggestions , as this is a work in<br />progress.<br /><br /><br />Cheers,<br /><br />Xcusme
