Solenoid and starter issues

[Sebbieboy]

I'll try to be as quick as possible and clear:
Got a 78 20HP - the starter rope broke so I have been trying to build starter. I had a solenoid and a starter on it - but the starter had no gear. The solenoid only got the starter (without gear) to go when I banged on it so i knew it was busted. Got a new starter with gear and a new solenoid.
The new solenoid is a 3 pole one instead of the old 4 pole one I had and I was only able to attach to body on one end cause it doesnt fit perfectly.
I tested the voltage everywhere and this is what's going on:
- I get 12 V to the big pole solenoid from battery on big red cable
- I get 12 V to the little yellow cable (key switch) when I crank the key and 0 V when i don't
- I don't get the 12 V on little pole solenoid with the little yellow cable on it when I crank the key (THAT i really don't understand)
- of course I don't get the 12 V on the other big solenoid pole with big yellow cable when I crank key

So of course my starter doesnt go. Can anyone help me?? I am really confused - could a new solenoid be already busted?? Or could it be that am not grounding my solenoid well enough?? It seems pretty well grounded to me...
Any help will be greatly appreciated. Thanks

 

[kungpaoshizi]

Re: Solenoid and starter issues

I would look at the old one again or check in the manual which one you need. There could be current requirements etc..

 

[Sebbieboy]

Re: Solenoid and starter issues

So you don't think that any solenoid would work? I thought they all did the same thing? I got a automotive one I think I guess that wasnt a good idea right? Can you confirm? Thanks

 

[oldman570]

Re: Solenoid and starter issues

Saves a lot of time and troubles when you use parts that are made for the motor being worked on. You never want to bang on the starter with anything as it can and will knock the field magnets lose from the case and then you get to buy a new starter. 3 post and 4 post solenoids all need a good ground and to have the battery cable on the correct post to make them work as intended. JMO
Oldman570

 

[MH Hawker]

Re: Solenoid and starter issues

No do not use a automotive one unless of course you want to blow your self up. Now take apart ever connection no matter how good it looks and polish it that will solve 95 % or stating problems.

 

[Sebbieboy]

Re: Solenoid and starter issues

Alright so I got a second hand mercury solenoid from the dealership to make sure I have the right thing. Still doesnt work...I still get 12V to solenoid and 12V on switch key cable when i crank key. But i get a 0V reading when I put the key cable on solenoid when cranking key.
What do you guys think is the problem? Am I not getting enough power through solenoid to work?
MH Hawker - you said take every connection apart and polish it? How do I do that? At the end of the cables? Should I use grease like dialetic grease?

Thanks for the help everyone i really appreciate it.

 

[GA_Boater]

Re: Solenoid and starter issues

Is the solenoid clicking when cranking? Is the new to you/used solenoid 3 or 4 wire? 4 wire solenoid - On the two small poles, one is from the key switch and the other is to ground.

What is your serial number?

 

[MH Hawker]

Re: Solenoid and starter issues

A piece of 300 or so grit sand paper and a bit of polishing till its has a nice and shine and personally i use a bit of dielectric grease.

The pos and neg at the battery, and the pos and neg where they attach on the motor and the solenoid control wires and the wire from the solenoid to the starter.

 

[Sebbieboy]

Re: Solenoid and starter issues

Is the solenoid clicking when cranking? Is the new to you/used solenoid 3 or 4 wire? 4 wire solenoid - On the two small poles, one is from the key switch and the other is to ground.

What is your serial number?

No there is no clicking when cranking - the new used solenoid is a four pole - I tried switching the wires of the two small poles (guy at merc dealership said it didnt matter which one on which) and the serial number (# on back of the solenoid) is 89-68258.
Thanks for your help

 

[Sebbieboy]

Re: Solenoid and starter issues

A piece of 300 or so grit sand paper and a bit of polishing till its has a nice and shine and personally i use a bit of dielectric grease.

The pos and neg at the battery, and the pos and neg where they attach on the motor and the solenoid control wires and the wire from the solenoid to the starter.

Am going to try that - thanks

 

[Sebbieboy]

Re: Solenoid and starter issues

Alright so I cleaned the battery out - I used a metal brush for now - I need to get some dialetic grease. I tried just to see and now I get a click from solenoid when I crank (yeah!!). Still not enough to get starter going.
Am re-charging the battery as we speak just to be sure and am going to clean the cables later that go in and out of solenoid.

Any other suggestions?? Does it matter which small pole receives key switch and which goes to ground? I got no way to figure out which should be ground or key switch.

Thanks.

 

[MH Hawker]

Re: Solenoid and starter issues

For that you will need a print, if you will say the motor year and serial number they may be able to find you one.

 

[Sebbieboy]

Re: Solenoid and starter issues

So I have cleaned my battery and cables and put grease on them. I charged my battery and now am getting better readings. I hear the click when I crank the key, and I also get 12 V on the small pole when I crank which I wasn't getting before. So all of this is positive but I don't know where to go from there.
Any more suggestions?

 

[MH Hawker]

Re: Solenoid and starter issues

That click should be from the solenoid closing and applying voltage and amperage to the starter its self. Have you polished the connection points on the wire from the solenoid to the starter its self. If you have then I would have the starter tested.

 

[Sebbieboy]

Re: Solenoid and starter issues

Thank you MH Hawker you have helped me greatly.
Yes I cleaned the cables going to the starter and I tested the starter and it works great (it's new - custom made cause merc doesn't make it no more - and not on after market).

But here is the thing - while the starter was off the motor I tested the solenoid. And it works fine when the starter is not mounted; I get the 12 V out of the solenoid when I crank the key all the way to the end of the cable.
The PROBLEM is that for some reason when the starter is mounted the solenoid doesn't transfer no more.
What could cause this problem?
Can they get short circuited for some reason?
Thanks everyone.

 

[Sebbieboy]

What could be the problem?? Merc 78

What could be the problem?? Merc 78

Mistake didn't mean to post this

 

[MH Hawker]

Re: Solenoid and starter issues

That sounds like the polarity is reversed or the starter is losing the ground.

 

[Sebbieboy]

Re: Solenoid and starter issues

That sounds like the polarity is reversed or the starter is losing the ground.

What does having the polarity reversed mean? Thanks

 

[kungpaoshizi]

Re: Solenoid and starter issues

Polarity, for every circuit, the electricity needs somewhere to GO. So there's positive and negative. If you have the polarity switched, it's negative positive.

Pics might be nice if you have a camera of some sort?
Remember that a metal plate on a component that comes in contact with the engine mounts etc, can be the ground(negative) connection.

 

[Sebbieboy]

Re: Solenoid and starter issues

Polarity, for every circuit, the electricity needs somewhere to GO. So there's positive and negative. If you have the polarity switched, it's negative positive.

Pics might be nice if you have a camera of some sort?
Remember that a metal plate on a component that comes in contact with the engine mounts etc, can be the ground(negative) connection.

How do you fix having the polarity switch and how do I test that's the problem? I can post pics - solenoid and starter? Would that be helpful?