04 Yamaha 150 4 Stroke Wierd Electrical Problem

[kriscowan]

I have an 04 Yamaha 150 4 stroke. It was cranking fine this morning on a fishing trip, but then all of the sudden wouldn't start. There was a sound of faint alarm when the key was in the on position. When I turn the key to start the sounds stops and the engine appears to lose all power. I first thought it was a battery problem, so I swapped out the battery. When I connected the ground wires (1. main motor, 2. gauges and 3. accessories) to the battery it sounded like it arced. The engine continued to do the same thing it did when it was on the original battery. Make the faint alarm sound and then lose power upon turning of the key. I thought the arcing sound was odd, so I disconnected the gauge power wires and accessories power wires leaving only the main motor wires connected to the battery. It started right up and continued to do so. Once I got home I put the gauge wires back on and I would lose power when trying to start, but the faint alarm sound was no longer present. When I take the gauge wires back off the battery, the motor starts perfectly fine. Any ideas????

Kris

 

[Roncomania]

Re: 04 Yamaha 150 4 Stroke Wierd Electrical Problem

"When I connected the ground wires (1. main motor, 2. gauges and 3. accessories) to the battery it sounded like it arced"

Take note: arcing leads to sparks & heat and that usually can result in some type of FIRE! Keep your extinguisher handy! It definitely sounds like a short on the accessory cables. We had a similar problem on our 2004, 115 Yamaha, which ended up being inside the gray flex-tube that connects straight into the motor. Apparently, water had puddled inside the tube and started corroding the cables INCLUDING THE FUEL LINE!! We were lucky to get back safely that day because the fuel line was severely damaged by all the arcing and corrosion.

I would start with an ohm meter and check for resistance on the accessory lines. A quick easy test if you have the same gray flex tube- reposition the tube, (like raising it up), and check for any changes to resistance readings. That's how we found our corroded cable problem.

Electrical trouble shooting is just a process of elimination but you need the right tools like an ohm meter. Good luck!

 

[Capt Ken]

Re: 04 Yamaha 150 4 Stroke Wierd Electrical Problem

First your gauges are powered by the engine harness and are not connected to the battery. So that leaves the problem in the accessories. Try removing the fuses from everything and touch the wires back to the battery to see if it still arc'ed. It's going to be a process of elimination.