Merc. 470 Starter Solenoid Wiring Question for gear reduction starter

[67Bertram]

I started another thread about this but I was not clear in what I am trying to do. So let me lay it out as clearly as possible. My 190 HP Merc. 470 starter had a slave solenoid and none on the starter. I am now replacing that with a smaller and lighter gear reduction starter that does have a solenoid attached to it. After reading through many posts on the subject I am still not clear on exactly how to wire these two solenoids together. IF it makes a difference the boat is running an alternator not the original charging system. Any help would be appreciated.

 

[Bt Doctur]

The latest diagram shows the solenoid wire going to the starters solenoid post. Yellow/ Red. Use it in place of the slave solenoid.

 

[67Bertram]

Bt Doctur, I assume this diagram is from a later model engine that had the original configuration of two solenoids. Mine came from the factory with only the one slave and none on the starter. not sure if the wiring would be same or not. Thanks for puling it up. I will take good look

 

[kenny nunez]

Obtain another large cable that has eyelets on both ends known as a "switch to switch " that will reach from the large post on the original solenoid's main battery connection and secure them on the post. Attach the other end of the added heavy cable to the main large stud on the new starter solenoid. On the other side of the primary solenoid remove the large cable and make up a #10 wire that will go on the post and attach it to the "S" terminal on the starter solenoid.

 

[67Bertram]

Thanks for all the help. Went down to the boat after work and swapped out the starter (no fun BTW) got it wired up with the help of you guys and all is well. Thanks again!

 

[stonyloam]

It is better to use a heavy battery cable directly from the battery pos terminal to the heavy stud on the starter solenoid, just like in the diagram.

 

[67Bertram]

It is better to use a heavy battery cable directly from the battery pos terminal to the heavy stud on the starter solenoid, just like in the diagram.

That is what I did and it works fine. The only thing that I don't understand about this configuration is why I should leave the original battery cable on the slave cylinder. I would think that a 12 gauge wire would work fine too. Am I wrong? No reason to change it now, just saying....

 

[kenny nunez]

Leaving the battery cable is just an option , either way works. Sometimes the cable will not reach the starter, no 2 boats are the same.

 

[stonyloam]

That is what I did and it works fine. The only thing that I don't understand about this configuration is why I should leave the original battery cable on the slave cylinder. I would think that a 12 gauge wire would work fine too. Am I wrong? No reason to change it now, just saying....

You are correct, you are now just powering the starter solenoid AND the ignition coil during starting ( purple/yellow wire). the 470 slave is different from one on a 3.0 in that it provides voltage to the coil during starting, where on a 3.0 the voltage comes from the starter solenoid.