Starter Relay help

[nameless in nashville]

I have been told that it would be wise to run a starter relay on my mercruiser 350. I am in need of some help as to how it works and what it's actually doing. My relay has 4 posts, two fat ones, one on the left and one on the right. On the front of it there are 2 smaller terminals The one on the left is a ground. What I would like to know is, The 2 main posts connect my battery to the starter. And from what I can gather there is a magnet on the inside of the relay and it gets powered up by the two terminals on the front of it. Which once activated pull the 2 fat terminals together. Which line am I supposed to run to the front of the relay? Is it supposed to be a powered line going from the starter to the key switch? Any clarification will help.<br />-Gerry

 

[12Footer]

Re: Starter Relay help

This is a standard solenoid relay. The two small ones ARE to enregise an internal coil,(electromagnet)that pulls a big copper bar across the two bigger posts. If you were to take a fat screwdriver, and jump the 2 big terminals, sparks would fly, and your motor would crank.<br />The one small goes to ground, the other small goes to the "START" terminal of the ignition switch.

 

[nameless in nashville]

Re: Starter Relay help

Hmmmm, If I trip the two small terminals, should I hear anything going on in the inside? Or is it something that you wouldn't hear?<br />-Gerry

 

[nameless in nashville]

Re: Starter Relay help

Here's another stupid question, Do I need the relay if I have a solonoid attached to my starter? I just can't make sense of why I need this stupid thing!<br />-Gerry

 

[hondon]

Re: Starter Relay help

You are absolutely correct. You don't need an additional solenoid and would only be adding another point of failure.

 

[Walter]

Re: Starter Relay help

My V-8 MerCruiser came equipped with what I refer to the starter "slave" solenoid. This is in addition to the starter motor solenoid. I'm not sure why Merc engineered the slave solenoid into the starter circuit, but you'd think it's there for a good reason. Any of you MerCruiser experts (Fone_Man) know why?<br /><br />Walt

 

[fone_man]

Re: Starter Relay help

That is one thing I do not know... My question would be how to research that??? But I know they are there because people keep asking about them...<br /><br />Due to moisture/corrosion I have seen many solenoids stick & even mine but a V8 is harder to get to to disconnect the starter should this happen... is this the reason for for extra relay???... killing power to stuck solenoid/starter package or because they used a variety of power plants some that required this relay/solenoid and used a standard/generic harness... who knows but it was probably some engineer that gave a great presentation at a non-functional meeting & they had to show something for it??? Who knows but it seems to me a waste of time & energy!!! <br /><br />Disclaimer: This is NOT an answer but an opinion & you know what opinions are like!!!<br /><br />

 

[12Footer]

Re: Starter Relay help

Gerry, to answer your first question, yes, you should hear a "click" when the key is turned to "start".<br />To test it, the small lead not going to the engine's chasis can be jumped to the large terminal comming from the battery.<br />Even if it is bad, it may still "click".<br />To finish testing, use a battery jumper cable,and jump the large battery terminal to the large starter terminal. <br />As far as why there would be a redundant solenoid, I have no clue. It may be seperate starter motor and bendix engaging solenoids.<br />Just guessin tho.

 

[ODDD1]

Re: Starter Relay help

starter 'slave' solenoids are used because of the high current demand of the solenoid mounted on the starter...we are talkin upwards of 30 amps on a hot start here...run 30 amps up a little wire to the key switch, an all the way back to the starter, an you dont have enough left to energize the solenoid....so the need for a smaller slave solenoid to activate the big one....mercruiser doesnt put stuff on their engines for no reason....it needs to be there...

 

[fone_man]

Re: Starter Relay help

ODDD1:<br /><br />There has to be another reason... because GM has been using the same starter & solenoid application for years without a slave solenoid & uses same "small" wire from ignition switch located on steering column. What gives... if this is so important why do I not have one on my Mercruiser...???<br /><br />

 

[hondon]

Re: Starter Relay help

Think back ODD. I' ve yet to see a GM/MERCRU. with a slave solenoid.OMC stringers used them.

 

[12Footer]

Re: Starter Relay help

Some Dodges had them,didn't they? Slant-six?<br />But ODDD1 said it all. They wouldn't waste the greenage on redundant parts ifn it didn't need it.

 

[ODDD1]

Re: Starter Relay help

Thanx for the backup, 12 footer... these 2 guys [foneman an hondon] actually made me go look today.....every GM product mercruiser sold had a slave solenoid on it...good lord, I have changed enough of them over the years....only motors that had only one solenoid were the ford product [1970's], or the 3.7 liter motors with the prestolite starter...

 

[hondon]

Re: Starter Relay help

I think we have some miscommunication here.ODD are you telling me that all GM MERCRUS.had two starter solenoids?My experiance has been quite different.I beleive that was the ?posted.