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ignition switch change

Here is something that may help you diagnose the problem:

The Starting Circuit
  1. When the key is turned to Start, the “S” terminal of the key switch is energized and power flows via a yel/red wire to the neutral lockout switch in the throttle quadrant.

  1. If the shifter is not in neutral, no power will flow to the starter circuit. So if all else seems normal, and the starter will not crank, and there is no solenoid click, check the neutral lockout switch.

  1. From the neutral switch power flows aft via a yel/red wire to pin #7 of the 10 pin plug, then to the slave solenoid. When the slave solenoid closes, +12 volt conducts from a large red/pur wire (from the 50 amp breaker) to the starter solenoid S terminal via a yel/red wire. This closes the starter solenoid contacts and sends high current +12 volts from the B terminal to the starter windings.

  1. If there is no audible click when the key is turned to Start, the slave solenoid may be bad, or power is not getting to it’s yel/red wire terminal. The key switch could be bad also.

  1. If the slave solenoid clicks OK, but the starter won’t turn; check with a voltmeter to see if +12 volts is getting to the S terminal on the starter solenoid. If so, the starter or starter solenoid is at fault, otherwise it’s the slave solenoid.

  1. Before the engine starts the voltmeter should indicate about 11 or 12 volts with the key switch ON. While the starter is cranking this may drop to 8 or 9 volts. If it drops lower, suspect bad battery wiring or a weak battery.

  1. The solenoids switch the high current needed for the starter, and prevent the need for long runs of heavy wire up to the instrument panel. The slave solenoid is usually found close to the main breaker, sometimes on the same bracket.
Rod
 
No, I have a friend with some knowledge to help me test everything. What's the difference between a starter solenoid and a slave solenoid?
 
Thanks for the help! That's a perfect answer. I'll check it all out. It seems like a switch because it's silent when you turn to start then if you keep trying it will engage the starter like normal.
 
One way to confirm the key switch function is to jumper the B terminal to the S terminal on the back of the switch. If doing this turns it over everytime, its your switch for sure.
Make sure you replace it with a marine certified switch.

Rod
 
Went to the boat today, instructions in hand. So here's my dilemma. Where on a 1999 Merccruser 4.3 EFT is the slave solenoid? Looking at the parts online I can't seem to find anything resembling that on the motor. Can anyone point me in the right direction and possibly provide a picture? Many thanks, Jim
 
Looks like this
Usually on front of engine strb side. May also be on top of engine by one of the risers. Could be under a cover.
8996158T.jpg
 
Find the 50 amp breaker RED reset button next to the front of the starboard valve cover, it's right behind it.
 
On my 1996 4.3 it was located on the port side of the distributor, right in front of the 50 amp main breaker. Behind and to the port side of the carb.

Rod
 
That's too funny. I'll figure it out. The engine sure has a lot of stuff on it. My last was a 1985 5.7 bravo. This is my son's first boat. She gets up and goes though.
 
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