Yamaha 115 f intermediate charging

[richardgp]

I can start the motor and take cruise for 45 min during which it shows charging @ 14.8... Then it will go to 12 volts.sometimes it moves up to 12.2 or as high as 13 for a second. Then back to 12.
Then I return home and restart it after a hour or over night and it will then start to charge at normal voltage up to 14.8...
All battery cables seem to be tight at the batteries.
The first time it did that it went to a flashing 12 volts. Tightened battery cables and no more flashing.
What is the most likely problem.

2004 115 hp 4 stroke outboard with 130 hrs

 

[jeffersondodson561]

Re: Yamaha 115 f intermediate charging

I think what you are seeing is the normal operation of the regulator, right after you use the starter it is going to replenish the lost energy of the battery. Use of power trim or other heavy load bearing devices will do this as well. What kind of battery are you using? Yamaha charging systems don't like the glass mat (optima) batteries, should not be a deep cycle battery, should be a cranking/starting battery.

 

[Silvertip]

Re: Yamaha 115 f intermediate charging

If all you did was tighten the cables but did not clean them, then that is likely part of the problem. Remove them, clean them thoroughly and tighten securely -- on both ends. Loose or corroded at the engine end is no different than loose or corroded at the battery end. The charging system should not drop to less than 12.6 at any time, except during the initial start and during the initial charging process. You will see a gradual rise in voltage up to the regulated 14.6 or so. Then you may see a drop off but it should not drop back below 12.6. Like speedometers, console volt meters are not as accurate has a hand held mutli-tester. Make voltage checks using a quality voltmeter.

 

[richardgp]

Re: Yamaha 115 f intermediate charging

So you say it is normal to be running along with yamaha volt meter reading in the 14's and then instantly it drops to 12. and may not go higher until it is shut down and wait an hour or more then restart, at which it is going to level off at 14.8 at fast idle.????

 

[Silvertip]

Re: Yamaha 115 f intermediate charging

I did not say that. I said it is common to have the starting battery slightly discharged from running lights or a radio, or a locator for a couple hours. When you start the engine the voltmeter does not INSTANTLY go to 14.6 volts. It builds slowly to that level. How quickly that happens depends on the alternator output capacity. Once under way it should NOT drop below 12.6 volts unless you suddenly switched on a high current draw accessory and even then it would be only a quick bounce. It would appear that the regulator is getting hot and failing only to begin working again until it heats up again. If all connections are clean and tight then more thorough diagnosis is required. You might even try a different battery as the one you have may have an internal short that "loads" the alternator when the short happens. A fuse would not blow under that condition because there are none between the battery and the engine and besides, the problem would be inside the battery, not outside.

 

[richardgp]

Re: Yamaha 115 f intermediate charging

This is an outboard, stator/rectifier system.
Same outcome if on battery 1 or 2 or both..
Both batteries individually show 12.4 when key is on,motor not running.
My experance with outboards would be a new rectifier. Was hoping for some reassurance before I drop two c-notes....

 

[Silvertip]

Re: Yamaha 115 f intermediate charging

12.4 is not unusual for a static battery test with no load after sitting for a bit. As I said, use a hand-held meter that is known accurate. I certainly would not pop for a new rectifier -- besides, there are tests that can be done. Rectifiers don't usually become intermittent -- they either work or they don't. Regulators may indeed become intermittent. If the regulator and rectifier and a combined unit, then there are tests for that component as well but you need a service manual for those tests. I still contend you have some intermittent connections somewhere in the system. Check the plugs and sockets on the harness running to and from the the rectifier/regulator. Disconnect and reconnect them. Check inside the plugs/sockets for evidence of corrosion.

 

[mrb503]

Re: Yamaha 115 f intermediate charging

I have the exact same problem on my 2005 F115. I replaced the regulator with a new one and the problem still exists. I then removed the plug into the regulator and saw that one of the pins looked like it had been hot and melted some of the plastic away. It almost appears the connection was a bit loose which would explain the intermittent problem and the heat. Been trying to find a replacement wiring harness but cant seem to find the right one. Any help???

 

[richardgp]

Re: Yamaha 115 f intermediate charging

I replaced the rectifier last week and so far it is working great. Yesterday I did 28 miles on Atlantic Gulf stream fishing trip for Dolphin at Key Largo.
It charged from 14.6 to 14.8 all day except for one moment it went up to 15 volts which I think is too high. Never dropped below 13. volts even at 5 mph while trolling with all electronics operating.

mrb503 -- I wish I could help you. I thought that plug may have been my problem. I had unpluged and repluged it several times. No change.

 

[richardgp]

I start it at my dock, it runs perfectly, then I go about a mile at fast idle to go fast zone.
I then trottle up to try to plane off and the engine just sputters an falls on it face..
It will not go any faster, just sputters untill I trottle back then it runs great at about 1100 rpms or so.
Then I turn off key and it a couple fo secomds restart the engine , put it in gear , hit the trottle very hard and the boat jumps up and runs up to 30 mph ao so like it should . I then run between 20 and 30 mph it runs fine.
If I the pbring it to an itle and hammer it again it usually runs up to top end with very little surge.
I have a 2004 yamaha 115 four stroke o/b. on a 19 ft center console Key West.
Whats the problem ?

 

[99yam40]

you will probably get better responses if you start an new thread with all info,
as this has nothing to do with charging problems and is a very old thread