1988 J150tx getting 12.89 v

[71Windsor]

Hello again. I keep coming back and seeking your knowledge. (which is not unappreciated). But once again I need some pointers.

Engine: 1988 J150TXCCM

Ive never had a battery die while out running but just for maintance on the battery I will frequently put it on the trickle charger before I know I'm heading out. Just because I know a sitting battery can cause problems if it drains down. I know with auto alternators if you run on a low or weak battery it will burn the alternator up since its design is to maintain not charge. I'm sure marine charging systems are similar.

Now. At idle I'm showing 12.60 and when I bump it up I have 12.89 at the battery and that's the peak I get even while running around 80% throttle. I do not have a tach which I know is foolish but I've got a plug in test tach I use from time to time to check rpm at wot. It's just a simple clip on the plug wire type. Any way. I feel like while 12.89 is better then a drop in voltage it's still much lower then desired to maintain the battery and running accessories which I'd imagine to be 14.1.

Can I continue running only getting just under 13v? I did buy another r/r just because it was the right price. I already placed my order for the gasket just to be safe. Should I change the r/r or wouldnt that help my situation? I'm assuming the stator is ok since I do get a increase of voltage and guessing the regulator side of the r/r is bad not allowing correct volts to pass through.

I checked the two yellow wires and it looks like they are both 6.## volts. Your advice and guidance would be great. Thank you in advance.

Oh lastly. 3 years ago I told my buddy to just put the new battery in the boat he decided to go one step farther and hook it up. And of coarse not paying attention hooked it up backwards. Dont know if that's relavent but it couldn't have been good

Again thank you

Frank
Pennsville Nj

 

[Will Bark]

Re: 1988 J150tx getting 12.89 v

What voltage are you showing on the battery before you start the engine? My 1987 150 shows 12 volts and then when I start the engine it slowly builds up to 13-14 volts after running it around the lake for awhile; mine is a 9 amp charger so it's not going anywhere real fast on the charging. Sounds like you were lucky on the misconnection of battery since most times that would fry theR/R.

 

[emdsapmgr]

Re: 1988 J150tx getting 12.89 v

12.5 or 12.6 is considered "normal" battery voltage on a charged battery. The older V6 engines which are unregulated (rectifier only) would constantly charge the battery. When the battery would charge up, the voltage could creep up to as much as 16+ volts after running the engine for 20 minutes on plane. Your newer model has a water cooled combination rectifier/regulator. It won't let the engine charge as high. 13.5 volts might be more typical on this type engine. At this point, the voltage differences between 13.5 and 12.89 are relatively small. Variances in your voltmeter might even explain the difference. If the battery was hooked up backwards on this boat a some point, that could explain your problem. The rectifier/regulator bears the brunt of this hookup mistake. Since you've got a new one on it's way, I'd be inclined to put the new one in. FYI, when the engine is running it does not use battery voltage for the ignition-it makes it's own ignition power in the stator. The only time the engine would use battery voltage when running is when the trim is used.

 

[71Windsor]

Re: 1988 J150tx getting 12.89 v

Before I ran the engine the battery had 11.89 volts. I turned on the accessories and used the trim and tilt a bit until it showed under 12 and held steady. Then I fired it up and at the battery with the volt meter I have 12.89 holding steady. If I use the t/t it will dip to 12.05 ish and bounce right back. The r/r and gaskets are both here so I'm going to just swap it out and see what happens. Thanks again.