MP41080 Ignition switch

[hardwater fisherman]

Someone gave me a box full of boat and outboard parts.There is a 4 position push to choke Sierra ignition switch and I would like to use it on my 1972 25hp Johnson. There are 7 posts on the switch.The part I am not sure about is the one labeled I/ ignition and the one labeled S/ solenoid. I assume that the one labeled ignition goes to the small terminal on the solenoid. And the one labeled solenoid goes to the small grounded post on the solenoid. Also if the A/accessory post is left unused will the switch work?

 

[racerone]

Are there 2 posts marked M on this switch.-------Do not hook anything up untill you are 100% sure of what is going to happen when you turn the key !!

 

[hardwater fisherman]

Yes two M posts, so I would attach one kill wire to each? B to the battery and C to the choke?

 

[racerone]

Find a typical wiring diagram for your motor at----mastertechmarine---------

 

[hardwater fisherman]

I have seen the diagrams but I liked the fact that the choke,stop and start were all in one. Instead of three separate circuits.So if you are saying it wont work then okay.

 

[Joe Reeves]

Someone gave me a box full of boat and outboard parts.There is a 4 position push to choke Sierra ignition switch and I would like to use it on my 1972 25hp Johnson. There are 7 posts on the switch.The part I am not sure about is the one labeled I/ ignition and the one labeled S/ solenoid. I assume that the one labeled ignition goes to the small terminal on the solenoid. And the one labeled solenoid goes to the small grounded post on the solenoid. Also if the A/accessory post is left unused will the switch work?

Terminal "I" (Ignition" of the switch will have 12v applied to it when the key is in the ON or START position. Normally used with automotive ignition models.

The starter solenoid has 2 small 3/8" nut terminals... one nut terminal leads to a ground.... the other remaining 3/8" nut terminal of the solenoid would lead to that "S" terminal of the ignition switch.... 12v supplied to the starter solenoid to energize it when in the START position.

Four positions in that ignition switch... are you sure? (Off, ON, START, and what?) Are you counting the push in choke as one of them?

Seven terminals... are you sure again?... If so, what are they marked?

 

[racerone]

Hardwater----Only one wire from switch goes to the solenoid !-------See if there is a connection from B to C with switch " ON " and pushed in !-----Check it all out with your ohmeter before hooking up the battery and turning the key !

 

[hardwater fisherman]

No Title

It says on the package accessory-off-on-start so I called it 4 position. I saw that if was a three position then the model would be MP3XXXX instead of MP41080. If you count the two M terminals then yes 7 terminals.

 

[hardwater fisherman]

Hardwater----Only one wire from switch goes to the solenoid !-------See if there is a connection from B to C with switch " ON " and pushed in !-----Check it all out with your ohmeter before hooking up the battery and turning the key !

Thanks for your advice. I have not and wont hook anything up until I know for sure.

 

[F_R]

No Title

Like this, except the choke wire goes to the key switch "C" terminal instead of the separate choke switch. Easy!!

EDIT: The "I" terminal is not used with your motor, unless you want to connect it to a fuel gauge or tachometer, etc.

 

[hardwater fisherman]

Thanks I was just going to ask what the I terminal was for. EDIT And the A and the I terminal can be left unused?

 

[F_R]

Thanks I was just going to ask what the I terminal was for. EDIT And the A and the I terminal can be left unused?

Correct. The "A" terminal is hot when the key is turned to accessory position and also when it it turned to ON position. The "I" terminal is hot only when turned to on position. For instance suppose you have a radio that you want to work only when the key is turned to ACC or ON position. You would connect it to A terminal. The "I" terminal is for engines with battery ignition---which your motor does not have.

 

[hardwater fisherman]

Thanks.

 

[hardwater fisherman]

No Title

I have another question that I think involves the starting circuit.There is a safety switch behind the shift lock and the there are no wires running to it. And the ground wire from the solenoid is grounded to the bracket of the safety switch. On my 40hp the solenoid is grounded through the safety switch. This seems not right to me. Did someone bypass the switch?

 

[racerone]

Only one wire goes to that safety switch.----It looks as though there should be 2 wires, but it is only one.-----Looks like the function is bypassed.-Those safety switches are easy to take apart for cleaning.--------Do we need to say that 12 volts and wires can be very confusing to some

 

[hardwater fisherman]

Okay thanks. I am not confused.And it did not seem like any wires where ever attached to the switch. I can check it or replace it if needed.

 

[racerone]

?----They are easy to clean.

 

[hardwater fisherman]

Yes if it needs cleaning then I will do that. I have a couple to replace it with if needed

 

[F_R]

I have another question that I think involves the starting circuit.There is a safety switch behind the shift lock and the there are no wires running to it. And the ground wire from the solenoid is grounded to the bracket of the safety switch. On my 40hp the solenoid is grounded through the safety switch. This seems not right to me. Did someone bypass the switch?

Yes. They defeated the purpose of the safety switch. Probably because it is blown.

It is there to prevent starting in gear.

 

[hardwater fisherman]

Okay thanks I will check to see if it is blown. I think maybe because the shift lever was broken off , someone bypassed the switch because the shift lock could not make contact with the switch.