Starting problems with the 200hp Yamaha

[shaneburris74]

So I went to start the motor (1994 Yamaha 200hp carbed) this week in preps for the weekend. I got nothing but a humming sound from the motor. Opened the cover and the humming sound was the starter bendix spinning but never jumping up and engaging. I've been troubleshooting it all afternoon. My indications are kinda funky to me. I've went in circles a bit I think. I wanted to see what you guys thought. Here's what I have so far.

1. First off, If I take jumper cables and run them from the batt. directly to the starter, with the key switch on the boat in the on position, the bendix will engage and the boat will start and run......that would make you think the solenoid is the problem.

2. When you turn the key switch on and test the resistance across the solenoid you can see that the solenoid opens and routes power as it should.
..at least I think as it should.

3. There is 12v at the power terminal on the solenoid...WHEN CRANKING that power drops to around 7v......so I'm pretty sure 12v never gets to the starter. (or the starter pulls more than it should?...but why would it start connected directly to the battery).. I took the starter to an autoparts store and it's pulling 27 amps. I think that is within range. Also if the power wire is removed from the solenoid you don't get the power drop when turning the key switch..which leads me to believe the drop is do to the starter or solenoid.

4. Batteries are charged and tested with a voltmeter, when you turn the key you get 12v at the key switch (red) wire on the motor.

I'm kinda scratching my head now. Try to find a used solenoid and slap it on? What do yall think?

[shaneburris74]

Ok..call off the dogs. After posting I continued to read up on the problem. I took the battery cables and ran one from the battery ground post to the ground post on the starter...cranked right up...I gotta bad ground somewhere. I'm sure most of you smart guys were gonna tell me that. Looking back at my indications it makes sense. Now I gotta go find it.

[awthacker]

Shane, what boat did you end up getting? I saw your posts awhile back inquiring about the various engines on the boats you were scouting.

[spareparts]

Replace both battery cables, the Yamaha cables are made out of fine wire, they work real good for a while, but over the years of use, the wire breaks internally. You may find a place in it that was compromised and allowed water to enter the cables, they turn green and corrode up pretty quick. I see this all the time on older Yamaha engines. Run some new #4 cable(#2 if its a long run) with good cable ends and you'll be ahead of the game

[shaneburris74]

It was a bad ground running from the #1 battery. It was running to a terminal board that sends power out to bilge pumps and some other various stuff. The connection had gotten corroded at the terminal. While searching for it I just removed cables of the negative posts. As soon as I removed that cable all was well. Cleaned it up and its good to go.

I got a 94 21' Proline Cuddy.

Thanks for the help guys.