Voltage Regulator

I have a 77 Nautique with the PCM 351. I replaced the voltage regulator last year and corrected my charging issues. Worked great the rest of the year.
I took the boat out of storage this year and put it on the water. I am not charging again. I am assuming that the voltage regulator has gone out again. Is this common or is there something that I should look at that may be taking out the voltage reg?

If you find out that you have to replace the alternator, I suggest you get an internally-regulated alt, do a bit of re-wiring, and get rid of the voltage reg completely. BTW, NAPA has an exact replacement for the (expensive) regulator from PCM sources for 1/3 the price. Only thing is, it does'nt have the plug for the engine harness. Splice on the old plug.

hughes26 wrote: I have had the alternator checked and it was good. I was not getting and charge to the battery so I replaced the voltage regulator and it fixed my charging problem. I got it out to use it for the 1st time this year and I was not charging again.

8122pbrainard wrote: How did you determine the problem?

Can't say that I have fully diagnosed it this time around. The 1st time I was not getting a charge to the battery so I had the alternator checked. When it tested good the only other thing I knew it could be was the regulator. I replaced it and it started charging. So this time I am assuming that it is the same problem.

Belt tight? Sometimes you overlook the obvious. Mine wasn't charging, turns out belt was a bit loose, tightened and now charging fine.

All of the above are good suggestions. Another test you can perform is to apply 12 volts from any convenient source to the "Field" terminal of the alternator. If you immediately see a high charge rate, you can look to the voltage reg as a possible/probable cause of the lack of charging. Also could be wiring, battery, etc. One good place to look for trouble is at the plug where the engine harness plugs into the boat harness. It is near the rear starboard engine mount, just behind the starter. It is an 8-prong plug. It is common to find corrosion on the pins and in the holes that they fit into. This is a case of water + electricity = electrolysis = corrosion.

I have forgotten ....Does a '77 have an ammeter, or a voltmeter? In the case of an ammeter, the charging current has to flow from the alternator all the way to the dashboard and back to the engine, then to the battery. Lots of chances for a bad connection and lots of resistance even in a perfect situation. That is why most boat manufacturere changed over to voltmeters.    
Art

Thanks, Pete! In that case, the charging current has to make its way to the dash and back, lots of opportunities for loose/corroded connections, etc. Also we mustn't forget the main ground where the battery ground cable lands on the block. A popular place for rust/corrosion/looseness.

Since you don't have any charging issues, that leaves two possibilities: Either the ammeter itself has failed, or someone has put both the alternator wire and the battery wire on the same terminal of the ammeter, thereby taking it out of the circuit.

The most common fault with an ammeter would be simply a stuck pointer needle. If the meter had "burned out" meaning that the connector between the two wires inside had open-circuited, you wouldn't have any charging and none of your accessories would work.

The easiest troubleshooting would be to swap out the ammeter.

Art

I didn't find them all. Got amp/oil/temp/fuel. Got whole set for 25 bucks as I recall. PO had replaced tach,speedo and fuel guage(also new tank & line), so it doesn't all match. Hourmeter does not function, need to check that out too.

Thank you both, will check the back and/or swap.

I was checking the charge at the battery with a voltmeter. I noticed the problem by watching my gauge. Checked the connection at the volt regulator and then the charge at the battery. I will be checking some of the other connections that have been mentioned this weekend when I get back to the lake.

If I change the alternator to a single wire with an internal reg, what alternator should I use?

Discount Inboard Marine was very helpful.

www.skidim.com part numbers:

1206 - Aletrnator
1208 - Wiring Harness