Electrical Problems and Stereo Help?

[FTAC03]

I have recently acquired an 87 Centurion with the falcon hull. It is a good looking boat and most everything seems to be right except for the electronics. I show about 11 volts on the gauge when I turn the key on. If I turn the radio on it goes to about 10 and the radio will cut out at any volume. When running if you turn the bilge and radio on it pulls the volts down enough that the motor starts missing. I don't know what to do I have replaced the battery twice and had the alternator checked. The radio is stock except for the head unit. No amps until I get this electrical problem fixed. I also replaced the terminal connections at the battery and cleaned the ground at the motor. THe only thing I can think of at this point is that back on the motor there is a circuit breaker and that may be corroded. Will testing the resistance across the circuit breaker show me if there is enough corrosion on the breaker to pull the voltage down? I am desperate to figure this out and would like any and all suggestions. Thanks - JLW

[wesgardner]

I loose about a half of a volt from my battery up to my gauge cluster...I associate it with just being an old boat that could use a re-wiring (I'll never do it until it gets really bad) but I assume the main wiring harness's "hot" wire from back aft might need to be re-pulled.

I had starting issues and one of the fixes was t opull in a new wire from the "S" terminal on the keyswitch back to the solenoid - made ALL the difference...this was on a tip from my good friends at Mammock's Motor Electric here in town - they said that wire HAS to be in top notch condition...well my old one "looked" OK, no corrosion visible, but....

I have since SOLDERED all of my battery terminal connections - no crimps for me...

Maybe the main hot lead was slightly undersized from the factory (very, very possible as everyone bulds things on a budget) and has since corroded down to the point where it's just not able to cope...

Remember, the marine environment ain't exactly the most friendly place for electronics in general

Good luck, post-up your progress/solutions...

[tmbrown]

i noticed some irritating issues with my cables, and just replaced the battery leads... and also replaced my main power lead to my accessory panel - fixed all my issues. the more I went through the factory harness, the more corrosion I saw and had to replace many wires around the engine. I'd think you're on the right track checking for resistance - there should be none in most cases... but that won't tell you if the wires can handle the necessary amp load. In many cases though checking voltage will help, since you're showing low voltage...

Check the battery + against the block - to see if it's getting a lower reading than the battery negative - if not, ground block looks good, so use ground block and test positive at the alternator and at the starter - see if it's dropping there... continue tests like that... test the positive at the stereo with a known good ground, then vise versa... that should let you confirm/eliminate problem wire runs.