150 EFI charging problems

1996 Mariner 150 EFI,problem is, when running down the lake the volt meter is pegged over 16 volts.Any suggestions appreciated

Re: 150 EFI charging problems

Can you give us the serial number of this motor? Is it a 2 stroke or 4stroke ?

Re: 150 EFI charging problems

I have a similar problem only mine is intermittent.

Mercury 135 Blackmax Built 1994

Engine has been running like well over the years with little trouble. Recently I had a problem with the Oil Injection horn sounding?long story short it was the Warning module. I mention this because I reckon this might have been damaged by Over Charging.

For the last 7 years the Volt Meter (verified by the Voltmeter in the Fish Finder) Has been randomly swinging between 14.1V, !6.0 and 21Volts? There seems to be correlation between engine temperature, vibration and time.
The Battery is still good so didn?t worry too much about this?till I paid a fortune for a new the warning module that is.

Any ideas would be appreciated?

Re: 150 EFI charging problems

First, clean all battery terminals/cables, BOTH ends.

Second, check battery acid level. With a hydrometer.

Third, charge, load test battery. How old is it?

Generally even on an UN-regulated outbard charging system, the battery serves as the voltage limiter, to a great extent. Battery voltage will not rise very much over 14.2 until the battery is well aged and plate deterioration actually requires higher voltage to fully saturate the plates.

Re: 150 EFI charging problems

serial # is og325657 1996 150 Mag efi 2 stroke.I think I have found the problem.one of the voltage regulators has some soft plastic gunk running out of it and also found what looks like solder spray on the back side of the aluminum plate that holds the coils.Any idea what could have caused this?Boat has been running fine,with no battery problems.I just noticed the volt gauge was running high and did some investigating.

Re: 150 EFI charging problems

CHARGING & STARTING SYSTEM

Battery Charging System Troubleshooting
General Troubleshooting
A fault in the battery charging system will usually cause the battery to become UNDERCHARGED.
A defective voltage regulator or a stator winding shorted to ground may also
allow the system to OVERCHARGE the battery.
If a problem exists in the charging system, visually check the following:
1. Check for correct battery polarity [RED cable to (+) POSITIVE battery terminal].
*NOTE: 40 AMP CHARGING SYSTEM voltage regulator/rectifier is protected internally
against incorrectly installed battery cables.
2. Check for loose or corroded battery terminals.
3. Check condition of the battery.
4. Visually inspect all wiring between stator and battery for cuts, chafing and disconnected,
loose or corroded connections.
5. Excessive electrical load (from too many accessories) will cause battery to run down,
even if the system is operating correctly.
If the system is still OVERCHARGING the battery, disconnect the YELLOW wire connector
from the regulator(s). Check for continuity between either YELLOW wire and ground
which would indicate a shorted stator winding. A short to ground in the stator bypasses
the regulation circuit of the voltage regulator resulting in overcharging of the battery. If the
YELLOW wires are not shorted to ground, the voltage regulator is most likely defective
and should be replaced.
If the battery is undercharged, proceed with regulator, stator, and rectifier tests, following.
40 Ampere Alternator System
40 AMP STATOR TEST (ALTERNATOR COILS ONLY)
*NOTE: Stator can be tested without removing from engine.
1. Disconnect YELLOW stator leads from voltage regulator connectors on starboard
side of engine.
2. Use an ohmmeter and perform the following test:
Test Leads To- Resistance
(Ohms)
Scale
Reading
Connect test leads between 2
YELLOW stator leads at each voltage
regulator connector.
0.18-.45* R x 1
RED test lead to 1 YELLOW stator
lead (voltage regulator connector),
and BLACK test lead to engine
ground if stator is mounted or to
steel frame of stator (if off engine)
No
Continuity
R x 1000
*NOTE: Resistance of these windings is less than one ohm. Copper wire is an excellent
conductor but will have noticeable differences from cold to hot. Reasonable variation from
specified reading is acceptable.
3. If meter readings are other than specified, replace stator assembly.


I hope this help you Post back what you find