Solenoid function???

[saumon]

Hi,<br /><br />first of all please excuse my english (i'm french speaking). <br /><br />I recently went throught the process of replacing the starter solenoid on my 1993 Merc. 60hp 3 cyl, cause the starter sometimes stay engaged and i had for you guys a question.<br /><br />i understand that a solenoid act as an electromagnetic switch i.e when the ignition switch is turned past the "on" position, current is sent to the solenoid that close too and then the circuit is compltely closed so current goes throuht the starter motor. What i want to know is: why is there a second swith (the selenoid) instead of wiring the ignition switch directly to the starter motor? Did it act as a safety feature?<br /><br />Thanks for your input!

 

[JasonJ]

Re: Solenoid function???

Because the ignition switch would need to be built to withstand the amperage involved in turning the starter (standard ignition switch would melt). You would also have to have large, bulky wires running up to this huge, bulky switch. It is much more desirable to have the starter wires as short as possible to prevent amperage loss. This is why you have the solenoid. You are getting a lighter more compact ignition switch, smaller wiring leading from the ignition switch to the solenoid, and less amperage loss over the shorter starter wires. I hope this sort of helps.

 

[saumon]

Re: Solenoid function???

Thanks a lot for taking time to explain it, i really understand well now. It make sense.

 

[Perfidiajoe]

Re: Solenoid function???

Think of a solenoid as a device using small amounts of electricity, to control large amounts of electricity. Keeping that in mind will help you diagnose many starter/solenoid problems. Good Luck, Joe

 

[steelespike]

Re: Solenoid function???

Keep in mind the starter switch can also cause the starter to hang up,"stay ingaged"

 

[saumon]

Re: Solenoid function???

Originally posted by steelespike:<br /> Keep in mind the starter switch can also cause the starter to hang up,"stay ingaged"

Yeah, I know. It coud be caused by the ignition switch OR the solenoid. As this condition never happened again, i couldn't tell for sure wich one failed, so i replaced the one that I think is more prone to fail. I think i'll play safe and replace the switch too, a lot less expensive than a fried starter motor.<br /><br />Thanks guys!

 

[TOHATSU GURU]

Re: Solenoid function???

Keep in mind that the bendix assy on top of the starter, will also hang up and or disengage if it has a problem.

 

[saumon]

Re: Solenoid function???

Thanks, but I don't think it's the bendix cause when it happenned, i heard an intermittent grinding noise and when i look at the starter, i see the gear going up and down, touching the flywheel than going back, so i assume the bendix assembly is working properly and not stuck (but i could be wrong). Like i've allready told you, it just happenned once, so it's hard to diagnose.

 

[JasonJ]

Re: Solenoid function???

It might not be a bad idea to put just a bit of lube in the bendix assembly. I had to on mine because when the outside temps are cold, it wouldn't go all the way up and engage the flywheel. It would hang up just short, and drop once I released the ignition switch. Now it engages every time.