Need help with slave/starter solenoid

[zang8027]

See picture. I am not getting spark and I found two solenoids on the boat in the starting circuit. I have a feeling the slave is not hooked up right. Why do I have 3 grounds? It ran last year though and nothing changed to my knowledge??

Left side runs to neg battery
Left front runs to mount/ground
Right front runs to ign coil
Right runs to neg battery ??

Key off (on) voltage
-----
Left side 0 (0)
Front left 0 (0)
Front right 0 (4.7)
Right side 0 (0)

I should be getting 12v, not 5 right? How should this slave sel be wired?

MCM170

 

[Don S]

Re: Need help with slave/starter solenoid

What engine we working on?

 

[zang8027]

Re: Need help with slave/starter solenoid

On the second solenoid, there is no "key" voltage coming to it. I am not sure how that one is getting power

 

[zang8027]

Re: Need help with slave/starter solenoid

MCM 170 Alpha One

 

[dubs283]

Re: Need help with slave/starter solenoid

by the looks of the picture the solenoid is quite corroded and possibly automotive - just replace it with a proper one

no way to tell from the photo if its wired correctly, only red and black wires, have no idea - not sure if its mounted in the correct place either

this may help:

http://forums.iboats.com/mercruiser...ting-your-engines-starting-system-167035.html

 

[glenn property of pam]

Re: Need help with slave/starter solenoid

we are only getting 5v when i should get 12.. taking a look to see why. I get 12 up at key..unhooked from coil i get 11.5. hooked up I get 4?

you are getting false readings as the volt meter puts no load on the electrical system. you are getting 12 at the key with no load but once a load is added that could be as low as 4v due to a poor connection. start at the battery and remove then clean all the connections then see if you get 12 at the slave solinoid. The dirty connection can be anywhere from the battery to the tabs on the key to the solinoid (may even be internal to the key but that you will spot on a test). The solinoid is acting as a load so that will help you track the problem as you are looking for the voltage drop.

 

[glenn property of pam]

Re: Need help with slave/starter solenoid

how many batteries do you have on the boat?
did this run last year or is this a new boat to you?

 

[Don S]

Re: Need help with slave/starter solenoid

Here is the wiring diagram, The makings in your newest picture are all wrong. You should have a solenoid that grounds through the base not the terminals.

View attachment 170 wiring.pdf

 

[zang8027]

Re: Need help with slave/starter solenoid

Ran last year for the 3 times I put it out. I have 2 batteries. 12v Size 27. So I see a purple wire running from key to ignition coil. Then from ignition coil it runs to the front right. Does not make sense, as all of the other cables are running to ground. What is the point of running power to the slave if it has no where to go. That is why I think this is wrong.. but it worked last year!

The engine is cranking but not getting spark. The cap and rotor seem to be ok, no corrosion.

 

[Don S]

Re: Need help with slave/starter solenoid

This might be a little clearer.

 

[zang8027]

Re: Need help with slave/starter solenoid

Hmm I don't have it anything like that. Can you confirm that the ignition coil should be getting 12v from the slave? That is my thought but its not looking like that

 

[zang8027]

Re: Need help with slave/starter solenoid

This almost seems to look like the other solenoid that is located right next to the starter on the port side.

 

[Don S]

Re: Need help with slave/starter solenoid

Hmm I don't have it anything like that. Can you confirm that the ignition coil should be getting 12v from the slave? That is my thought but its not looking like that

It will only get battery voltage while the starter is engaged. When the engine is cranking, the voltage is not 12 Volts, it will be less, but the solenoid bypasses the resistor wire to put battery voltage to the coil that is higher than what the coil normally gets from the resistor wire.

 

[zang8027]

Re: Need help with slave/starter solenoid

Should there be 2 sol's or just one? All these diagrams show one.

Here is my engine.

Solenoid issue - YouTube

 

[Don S]

Re: Need help with slave/starter solenoid

Should there be 2 sol's or just one? All these diagrams show one.

Yes, your engine should have two. The thing is, it's not located or wired like yours is. Post a picture of the starter side of your engine (below the manifold, above the heat exchanger).

 

[stonyloam]

Re: Need help with slave/starter solenoid

I think he has two slave solenoids, correct? From what I know about 470 engines that solenoid does not belong there. Your two solenoids, do you have one bolted to the side of the engine, just above the heat exchanger? That is your slave solenoid. Should have (small terminals) a r/y wire from ignition, a p/y wire to the coil +, (large terminals) r/p wire from large terminal on starter, r/y wire to starter solenoid. That is your starter slave setup. I have NO IDEA what the heck that other solenoid does.

 

[glenn property of pam]

Re: Need help with slave/starter solenoid

i dont think the one you have a problem with is a slave solinoid. sounds more like a solinoid between the 2 batteries linking the ground. you have said that one of the thick cables goes to a battery negative and the other goes to a battery negative is that the same battery or a diffrent one. Sounds more like some one wired the batteries so they link when the motor is running.
from what you have said the engine is cranking but you are not getting a spark is that correct?

 

[stonyloam]

Re: Need help with slave/starter solenoid

Yeah I would have to agree with glen, that solenoid would close when the ignition is on connecting something, who knows what. I would disconnect the whole thing, who knows what a fire/explosion hazard you have there. As for your spark, check to see that you have voltage on the coil + when you are cranking the engine. If you do, look to your points, most of the time that is the problem.

 

[Don S]

Re: Need help with slave/starter solenoid

I think he has two slave solenoids, correct?

Very well may be, kind of why I asked about a picture of his engine between the manifold and heat exchanger.
It's tough to troubleshoot a home engineered electrical system when you only see one part of it. (a really corroded one at that).

 

[stonyloam]

Re: Need help with slave/starter solenoid

Very well may be, kind of why I asked about a picture of his engine between the manifold and heat exchanger.
It's tough to troubleshoot a home engineered electrical system when you only see one part of it. (a really corroded one at that).

Don: Take a look at his you tube video (post #14) clearly someone has added a solenoid that does not belong there, the things people do :facepalm: