Yamaha 15 HP electric start not starting!

[smocosailing]

Is there an electrical schematic you can post? In my yamaha service manual it is a fold out in tha back.

 

[smocosailing]

Does this outboard have an ignition switch?

Would need to see a wiring diagram to be sure, those start systems are pretty simple. Power usually comes from the main fuse, to the ignition switch, to the start switch, neutral safety switch, and finally to the starter solenoid. Since you have eliminated the solenoid and the neutral switch, my guess is that you're losing power somewhere between the fuse and ignition switch, perhaps between the ignition and the neutral switch.

You can quickly test the integrity of the starter motor, solenoid, and battery by just jumpering the solenoid. Rig up a test lead from battery positive (where the battery positive cable attaches to the solenoid is just fine), unhook the positive coil wire on the solenoid and apply power to it, the starter should engage. If not, you have a poor connection somewhere or bad solenoid.

If it does crank, get a test light or voltmeter and follow that positive solenoid coil wire backwards until you find power again. This is best done with a wiring diagram to "light your way," so to speak.

I'm going to start this right now. Stay tuned!

 

[FuzzyGrub]

Hopefully you can soon in on it...View attachment 124381View attachment 124382

Any chance that the bottom page call out went to a different diagram? Some of them are not lining up with the diagram above it. Example, item #11 says battery, but it is a push-button switch. Item #8 says 20A fuse, but it is a ground.

 

[thill]

Just to be sure, swap out the fuse with a fresh one, and make sure the socket is clean. This will fix these issues occasionally. A partially burned fuse or poor connection may show 12V on a multimeter, but cannot carry enough power to do trip the solenoid.

How did you jump the solenoid? Did you jump across the main lugs, or did you jump 12V directly to the trigger wire or stud? This matters. Here is the sequence I usually follow:

1. Use a wire connected directly to 12v and touch it to the small start wire or stud of the solenoid. It should turn over if the solenoid is good and connected properly.
2. If it DOES turn over, the issue is somewhere in the start button circuit, and easy to find. Fuse, frayed wire, bad connector, etc. It's there somewhere.
3. If it DOES NOT turn over, then check the ground wire of the solenoid.
4. Sometimes, a solenoid will be replaced with the ground connected to the wrong stud, and the solenoid won't work. Double-check the wiring

I hope this is helpful. You WILL find it, probably soon if not already.

 

[smocosailing]

Just to be sure, swap out the fuse with a fresh one, and make sure the socket is clean. This will fix these issues occasionally. A partially burned fuse or poor connection may show 12V on a multimeter, but cannot carry enough power to do trip the solenoid.

How did you jump the solenoid? Did you jump across the main lugs, or did you jump 12V directly to the trigger wire or stud? This matters. Here is the sequence I usually follow:

1. Use a wire connected directly to 12v and touch it to the small start wire or stud of the solenoid. It should turn over if the solenoid is good and connected properly.
2. If it DOES turn over, the issue is somewhere in the start button circuit, and easy to find. Fuse, frayed wire, bad connector, etc. It's there somewhere.
3. If it DOES NOT turn over, then check the ground wire of the solenoid.
4. Sometimes, a solenoid will be replaced with the ground connected to the wrong stud, and the solenoid won't work. Double-check the wiring

I hope this is helpful. You WILL find it, probably soon if not already.

I jumped the solenoid by connecting the battery directly to the starter motor ground and the positive wire leaving the solenoid.

Can I ask what you mean by 'wrong stud?' I broke the head off the original stud when I was reassembling it earlier so I've been using a different one. In another forum chat I was advised that this was ok to use so I thought this wasn't the issue. NOTE: These problems happened before I relocated the solenoid ground to this new stud location

 

[smocosailing]

Just to be sure, swap out the fuse with a fresh one, and make sure the socket is clean. This will fix these issues occasionally. A partially burned fuse or poor connection may show 12V on a multimeter, but cannot carry enough power to do trip the solenoid.

How did you jump the solenoid? Did you jump across the main lugs, or did you jump 12V directly to the trigger wire or stud? This matters. Here is the sequence I usually follow:

1. Use a wire connected directly to 12v and touch it to the small start wire or stud of the solenoid. It should turn over if the solenoid is good and connected properly.
2. If it DOES turn over, the issue is somewhere in the start button circuit, and easy to find. Fuse, frayed wire, bad connector, etc. It's there somewhere.
3. If it DOES NOT turn over, then check the ground wire of the solenoid.
4. Sometimes, a solenoid will be replaced with the ground connected to the wrong stud, and the solenoid won't work. Double-check the wiring

I hope this is helpful. You WILL find it, probably soon if not already.

What do you think about moving the ground to this location (since the stud original stud location is broken)

 

[smocosailing]

I'm going to start this right now. Stay tuned!

Ok something definitely with the solenoid, since I'm able to jump it with your instructions. I replaced the solenoid already but maybe the grounds are not in the right spot (I had to relocate due to a broken bolt)

 

[FuzzyGrub]

I would think any spot on the block should be good for ground. Test with ohm meter and remove contact paint and use a star washer to "bite" in.

 

[MrGiggles]

I jumped the solenoid by connecting the battery directly to the starter motor ground and the positive wire leaving the solenoid.

That sounds more like you just jumpered the starter motor. You need to unplug the small trigger wire on the solenoid (likely has a bullet connector) and apply +12v to it. The other small wire will need to be grounded to the engine block, the pictured bolt would be fine as it seems there are several other grounds already terminated there.

The posted diagram does not appear to be correct, pictures of the starter relay would help us give you some direction.

 

[thill]

That missing ground for the solenoid would certainly cause the no-start condition.
If you can't extract the broken bolt threads, moving the ground wire to a good ground bolt is the right move.

I jumped the solenoid by connecting the battery directly to the starter motor ground and the positive wire leaving the solenoid.

You didn't jump the solenoid, you bypassed it completely. At least you are getting closer to solving the mystery.