2006 f150 voltage problems

[davindyson]

I have twin 150 hp 4 stroke that at idle are only producing 11.6 volts..I have checked voltage at batteries{2 months old} and starter on motor-no difference..a mechanic said batteries could be bad and motor charging system shuts down,that if I put new batteries in boat the motors would charge then.I am leaning towards bad alternators or regulators,because defective battery or not motor should make 13-14 volts even at idle.Any thoughts??

[boscoe99]

A defective battery can cause an excessive voltage drop. I would suspect the batteries and wiring connections before I suspected that two bad regulators failed at the same time. Easy enough to swap the rectifier regulators and see if there is any change.

Take your batteries and have them load tested. Or, take a good battery from your car and truck and use it to power the motor to see what happens.

An F115 only outputs 16 amps maximum to the battery. It does not take much of a bad battery to draw this amount, at which time the battery will bring the voltage down.

[davindyson]

F150 voltage problems

Both batteries are two months old..yes I will have load tested.I jumped boat off with cables hooked to truck and gauges read 12.6 with cable hooked up,disconnect cables and voltage slowly drops back to 11.6 within 30 seconds or so..I was thinking if alternators were putting out it should at least it would show some charging voltage.Would hooking battery charger up to battery and leaving leads and battery switches on all mess up alternators on motors..I have just always remove leads and isolated battery under charge from rest of electrical components..Thanks for the help.

[TownsendsFJR1300]

Both batteries are two months old..yes I will have load tested.I jumped boat off with cables hooked to truck and gauges read 12.6 with cable hooked up,disconnect cables and voltage slowly drops back to 11.6 within 30 seconds or so..I was thinking if alternators were putting out it should at least it would show some charging voltage.Would hooking battery charger up to battery and leaving leads and battery switches on all mess up alternators on motors..I have just always remove leads and isolated battery under charge from rest of electrical components..Thanks for the help.

You can leave the battery hooked up while charging. Its better for the battery to slow charge (say 2 amp) vs 10 or 50 amp over a longer period of time.

Static (non running, battery just sitting) fully charged should be between 12.8 volts to just over 13 volts FULLY charged.

With your jumper battery hooked up and the boat engine running, that charging system should be putting out close to, if not 14.0 volts.. Your strictly running off the battery, no charging (or very little) from the engine right now. Something is amiss...


BTW, BEFORE LOAD TESTING, the battery has to be fully charged...


Note: If BOTH engines are NOT charging, its very, very unusual for them to both go out at the same time.

I would be checking connections, by-pass any on/off "Perko" type switch, (known to fail over time/wear and tear), etc.

Checking voltage at the actual Yamaha postive and negative battery cables, (NOT AFTER any switches) may very well show the engine charging. If you have 13+ volts at those Yamaha cables, your issue is after that, "down the line"..

[TownsendsFJR1300]

BTW, its my understanding NOT to change settings (on/off/both) on the switch (Perko style-if equipped) while the engine is RUNNING.

If both engnes weren't acting up this thread is very similar to your issues:

http://www.yamahaoutboardparts.com/f...e-th23410.html

Might be worth a peek behind the VR.