Wiring switch to starter solenoid etc.

[whitejd12]

Hey all,

I got everything I need to convert my 72 Evinrude 18 hp (18202r) to electric start. The switch is Sierra and MP 51090. I have no idea what the switch colors mean. I'm sure I don't need all the wires, but need to know which ones to use and where to run them. Also, advice on wiring starter, solenoid, wire gauge size to use, etc. The switch has me baffled.

Thanks. Jeff

 

[HighTrim]

Re: Wiring switch to starter solenoid etc.

This should help. Only need 4 wires off key switch.

 

[HighTrim]

Re: Wiring switch to starter solenoid etc.

This should help. Only need 4 wires off key switch. I use 16ga for the small wires, except for the choke solenoid, for that I use 10 gauge green wire. The battery to solenoid and solenoid to starter cables I use 4 gauge wire.

View attachment 223416

 

[whitejd12]

Re: Wiring switch to starter solenoid etc.

OK Great. It's manuel choke, so no choke solenoid. What do I hook negative battery cable to? The starter only gets one wire hooked to it? I wish I could post a picture of this key, but can't. You can look up a pic of it though, Sierra MP 51090. It came with no instructions. I have a black wire, a red wire, a yellow w/red stripe, a yellow w/black stripe, and a longer black w/yellow stripe with connector on end and a pigtail wire of same color coming back towards key, and a purple/lavender color wire also w/a pigtail coming back. Which one do I use and what color goes to what? I think the longer black w/yellow is for the two kill switch wires coming off armature plate, but how do I hook those two wires to this pigtail setup?

 

[HighTrim]

Re: Wiring switch to starter solenoid etc.

Return that key switch and get one for magneto ignition. It will have w "M" posts on it. That is where the 2 black wires from the points go to.

The black heavy gauge from the battery negative goes to a good ground on the powerhead, usually a mounting bolt for the starter. The pos from the battery goes to the solenoid, then to the starter post as pictured.

 

[HighTrim]

Re: Wiring switch to starter solenoid etc.

Here is a more simple diagram to use. Instead of the stop button, those 2 black wires will go to the M posts on the keyswitch.

 

[whitejd12]

Re: Wiring switch to starter solenoid etc.

That sucks! I wish this switch would work. I can't really return it, they're an hour away and it was $42.00. UGH! Any idea of what switch to order or can I buy one local, hardware store, NAPA etc.

Jeff

 

[whitejd12]

Re: Wiring switch to starter solenoid etc.

Here's a link to a picture of the switch. I'd really like to be able to use this one if possible.

Amazon.com: Sierra MP51090 3-Position Ignition Switch: Automotive

 

[racerone]

Re: Wiring switch to starter solenoid etc.

Why not simply use a pushbutton for the " I want you to stop " function.-----Or call the seller to find out EXACTLY what you bought as far as using this switch for a magneto.---Use an ohmeter on the black wires to see what you get in the run and the off position.

 

[whitejd12]

Re: Wiring switch to starter solenoid etc.

OK can the negative battery cable go to any mounting bolt on the starter motor bracket or does it have to be the big long starter mounting bolt? Just trying to avoid removing the whole motor bracket and removing the big long screw.

Thanks Jeff

Return that key switch and get one for magneto ignition. It will have w "M" posts on it. That is where the 2 black wires from the points go to.

The black heavy gauge from the battery negative goes to a good ground on the powerhead, usually a mounting bolt for the starter. The pos from the battery goes to the solenoid, then to the starter post as pictured.

 

[racerone]

Re: Wiring switch to starter solenoid etc.

Battery negative can go to any suitable bolt on the block.--No need for it to be on the starter.

 

[whitejd12]

Re: Wiring switch to starter solenoid etc.

It already has a push button kill switch, but I have to remove that to bring cables in. I guess I can get another switch, just wanted get working on it this weekend.

Why not simply use a pushbutton for the " I want you to stop " function.-----Or call the seller to find out EXACTLY what you bought as far as using this switch for a magneto.---Use an ohmeter on the black wires to see what you get in the run and the off position.

 

[oldboat1]

Re: Wiring switch to starter solenoid etc.

I did a conversion using a push button starter switch, rather than a key. It's a two wire momentary button. Your '72 has a ring gear on the flywheel I think, so you must have found a starter and bracket. In place of the solenoid transom box, you can buy a plastic outdoor electrical box at Lowes.

Just looked at your #4 post -- must have a wiring harness. Rather than using the old harness, I did a simple new starter hookup -- advantage is that you use all new wiring (gauges indicated in a post above.) I would include a pic of the solenoid and starter button hookup at the transom, but the boat has a couple feet of snow on it yet.

 

[whitejd12]

Re: Wiring switch to starter solenoid etc.

No I don't have a wiring harness, those are the wires coming directly out of the brand-new key which I bought today. Apparently that keyswitch won't work, I'm going to have to buy a new one. I've already got the starter motor mounted in the bracket mounted to the motor I got the solenoid mounted and got the cables and everything I just got to figure out the key. ��

I did a conversion using a push button starter switch, rather than a key. It's a two wire momentary button. Your '72 has a ring gear on the flywheel I think, so you must have found a starter and bracket. In place of the solenoid transom box, you can buy a plastic outdoor electrical box at Lowes.

Just looked at your #4 post -- must have a wiring harness. Rather than using the old harness, I did a simple new starter hookup -- advantage is that you use all new wiring (gauges indicated in a post above.) I would include a pic of the solenoid and starter button hookup at the transom, but the boat has a couple feet of snow on it yet.

 

[HighTrim]

Re: Wiring switch to starter solenoid etc.

Im not 100% sure if you can get that to work on a magneto ignition. Maybe, using 2 wires, and simply use the kill button to stop. It is a much more expensive switch than you need though. All you need is a simple, cheap magneto switch.

Another option would be to just drill another hole in the cowl, and mount another momentary button beside the kill button, then use that as a start button. I just did this on a 25hp. I drilled a hole in the side of the cowl, added a grommet for my battery cables coming in, with some heat shrink for protection. Then drilled the hole and added the start button beside the kill button on the front plate. Just a quick job for someone that needed it that day, but it works.

 

[oldboat1]

Re: Wiring switch to starter solenoid etc.

sounds like you are close. saw the discussion about the key switch. BTW, the cables coming in to the motor (starter, in any case) should be the heavy 4 gauge stuff (mention that because the kill switch wiring is lighter than that. I drilled under the pan/lower cover to get the larger wires in.) Negative connection can go to starting bracket bolt (on factory electric, goes to a bolt on the other side of the powerhead, opposite starter.) As Racerone says, location isn't critical for the ground. Starter wiring shouldn't compete with kill switch wiring or assembly, though.

 

[oldboat1]

Re: Wiring switch to starter solenoid etc.

good pics from HighTrim. I installed the starter button on the transom box, but a number of options. If you fit the solenoid somewhere under the cover, it would be nice and tidy to put the starter button (or switch) at the motor.

 

[whitejd12]

Re: Wiring switch to starter solenoid etc.

Thanks for everyone's help. I think I understand everything now. I just need to buy a different switch. I don't wanna drill a hole in side of motor. I think I'm gonna mount switch actually in the boat back near the motor. It's a tiller steer. I got a rear seat back there and think I can make that work pretty good. I'll use the hole where the kill switch is now to bring wires in and out of. Will also install connector plugs in wires outside of motor for easy removal of motor from boat.

 

[F_R]

Re: Wiring switch to starter solenoid etc.

Why do you think the key switch won't work? I believe it will. It just has the new color coding.
Red on the switch is battery (same as green on the diagram posted by High Trim)
Yellow with red stripe goes to solenoid (same as white on diagram)
Black is stop (same as either black on diagram)
Black with yellow stripe is other stop (same as remaining black on diagram)

You probably won't be using the other wires. They are for choke and accessory feed, and battery ignition coil (you don't have any of that stuff).

 

[oldboat1]

Re: Wiring switch to starter solenoid etc.

just struck me, should get a fuse link in there somewhere (inline fuse).