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Blackmax 1995 Random overvolatge

G

geoffers

New member
"Hello, has anybody come acros

"Hello, has anybody come across the following over Voltage problem?

Engine 1995 135HP Black Max

Voltage will regulate to 14.1 Volts at any rev range. But occasional will increase to 16V and sometimes 21V, then will go back down to 14.1V. This can happen anytime and disappointingly there is no obvious correlation to time or engine temperature.

I’m thinking the problem has been there for years. I first became suspicious that something was not right about 5 years ago after fitting a Garmin Fish Finder. This shows system Voltage and occasionally would shutdown complaining about over Voltage!

I lived with this problem until last year when I had a problem with Oil Injection alarm randomly sounding. After a detailed investigation the problem was a damaged Alarm Warning module.

The engine is working fine but I still have the random over Voltage. I am now concerned this high Voltage is stressing other engine components too.

Some points –

I have verified with a meter that the voltage is real and have recently fitted a Volt meter to the dashboard to monitor in real time.

The regulator is the obvious choice but do semiconductors fail intermittently?

Another point - I have not necessarily been running the engine with the correct battery. I fitted a very good quality BOSCH about 6 years ago that is only 55APH. The battery itself has never been a problem and has plenty of capacity to crank the motor. The battery has no other function and it dedicated to the engine.
Interesting the battery is already quite old and does not seem to have been damaged by the constant over Volting?

Any ideas. your help would be appreciated before I starting changing Stator, Regulator Battery etc.

Many Thanks Geoff"
 
That is very old for a marine

That is very old for a marine battery. The first thing I would do is replace is with a MARINE starting battery.
 
"Geoffrey, semi conductors usu

"Geoffrey, semi conductors usually work or they dont sometimes they can fail when hot and reset when cold had a simular problem with a motorcycle not long ago turned out to be the stator.you can take you battery to a auto electrician who can put a shunt across the battery to check, my guess would be the stator."
 
"Regulators are trouble in the

"Regulators are trouble in these years, a lot of failures and fires. They usually go high when they go out. There are 2 silver boxes behind the coils? THe wiring looks all heated to hell?"
 
"Hi Bandit, I had chance to ge

"Hi Bandit, I had chance to get over to the boat and lift the cowl this weekend. You are right. Two yellow wires are showing signs of heating. The bullet connectors look like they can’t carry the current and have melted the rubber insulator. The metal contacts in the bullet connector are black and look like they might not be conducting well.

I will try and clean or even replace them and improve the electrical resistance…could this be the problem; these two wires making intermittent contact? Or is this wishful thinking and the ‘Regulator’ is goosed."
 
they all look like that. *

they all look like that. *** The module grounds are solid? *** Deep cycle batteries never worked well with these regs. either. Seems to make them get hot. Don't use the DC batt all by itself.
 
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