Kad300 tacho/low voltage thoughts please

[zt260]

Started starboard engine no problems and went for a total all systems okay.I went to restart the engine switched ignition on an tacho needle shot all the way round bounced about and went zero prior to starting.i then started engine as normal and tacho settled but the voltage is showing just below 12v on the gauge and won't engage forward till about 1000rpm when the voltage gauge comes up to 12v.I am thinking I may have a dry joint in the main control box as when I increase revs the voltage meter is not going above 12v.the alternator was new 2 years ago and have had no problems and no alarms also no diagnostics flashes.
I would be gratefull for your thoughts.I have the wiring workshop manuals but am no electrician


Regds ash

 

[spannerman]

First thing is check the connections on the alternator, and voltage on the B+ terminal on the alternator with the engine running, if the voltage is below 13.8 then you have an alternator or voltage regulator problem. If its above then work your way along the charging circuit, you should have the same voltage at the batteries and the ignition switch.If it drops off you have a bad connection somewhere, you should have virtually the same voltage all the way up to the voltmeter, if you have the right voltage at the meter then check its earth and if thats ok then the meter is defective. You are on the right track its just a process of elimination starting at where the power comes from.

 

[zt260]

Thanks will check alternator voltage next week
Regs ash

 

[zt260]

Checked alternator only getting 12v so changed for new one now getting 14v at 1500rpm.tacho still playing up on ignition but settles once engine is running
On to the next job


Ash