1972 Eating Batteries

My 1972 Correct Craft 302 ford has gone through three starting batteries this season. Any and all help would be appreciated.

Stats:

* I use only starting not deep cycle batteries
* battery reads 12.4V engine off
* battery reads 12.1V engine at 1500rpm
* battery reads lower volts after every trip to the lake until boat will not start.

Alternator test w/ multi-tester at 1500rpm

* with + on battery terminal and - on field terminal reading is 11.71V

* with + on battery terminal and - on stator
terminal reading is 11.67V

I have had the alternator tested and the testing machine gave it the ok. I do have a newer voltage regulator from an auto parts store. My initial thought was bad alternator, but it checked out. Could it be the wrong voltage regulator for my engine? Any other ideas? Thanks!

    Definately a charging issue. You should use a marine approved regulator anyways to be safe.

                                  Jeff....

i had a problem once where the voltmeter was at around 15 to 16 volts and kept cooking the batteries, it ended up being the volt. reg.

double post

The marine vs. automotive won't make the difference for you by itself, the marine spec parts are just better shielded from producing sparks and so are safer running in an enclosed engine compartment. Either way you need the correct regulator, Jeff was just saying while you are at it get the safer marine parts.

I think you should install a new regulator and measure the voltage while running. If it is around 13.5-14.5 volts you probably have solved the problem. If not you'll have to replace the alternator. I hate advising you to do the "swap a part and check it" routine, it gets expensive, but at this point I have no other ideas.

screw all that

your just going to chase your self.

Up-grade to a new internal regulated alternator from skidim and get the new wiring harness and fix the problem otherwise you are going to keep spending money and not fix it and still have to get a new alternator and wiring harness to fix it.

    Replacing everything is OK, but can lead into other issues, such as eliminating the ammeter. If the existing wiring hasnt been played and is in good shape, take the alternator and regulator to a repair shop and let them test it. My old 76 302 had a issue, it had a bad diode, and cost me $87 to have it totally rebuilt and tested, including the regulator.
    If you have some time and extra money to spend (or trying to run a large amp), go with the new one, or if you dont have a local repair shop.   My .02...

                                    Jeff...

Answers to questions:

* Multimeter test: with the + on the alternator battery terminal and the - on the engine block my reading is 11.75 volts at idle and at 1500rpm

* The regulator is not built into the alternator.

* I replaced the voltage regulator soon after I purchased the boat because the old one had oil on the terminal ends and would heat up and smoke until the oil would burn off. Also, the previous owner went through batteries and I thought a new regulator would fix the problem.

* I had the alternator rebuilt last summer.


I am going to pull the alternator today and have it tested again just to make sure it has not gone bad.

Thanks for all the input. Any more comments or suggestions?

Do what I suggested and be done with it.

I had the exact same problem did the exact same things other than charging the batteries instead of replacing them and as soon as I upgraded to the new alternator and harness from skidim it was fixed and never had the problem again.

Thanks for all the help!

The mystery has been solved. The voltage regulator has 4 terminals F,S,A,I. All the terminals had a wire connected to them but the A terminal. The A terminal needed to go to the hot side of the starter solenoid.

The original wiring diagram does not show this wire......... my other correct craft does not have this wire.........but that one wire did the trick..... I now show 14.2V across the battery while at 1500rmp.

The previous owner may have taken the wire off and not replace it, or it may have never been there. Has anyone else experienced this little glitch? How about a three wire only system?

My alternator rebuild shop said he has never seen a system where the A wire was missing and he has been at this for 20+ years. Anyway I had better hurry up and get her into lake again this weekend before winterizing.

Thanks again everyone. I am always inspired by the friendly advise and helpful exchange of information on this site!