voltage problem

[jvalhenson]

while running my 1998 225 ocean pro is only making 11.7 volts. should be 14+ and it has been getting weaker it seems as last week it was making 12.2. I have checked all the connections, grounds, batteries, etc and all seem fine. I replaced the rectifier/regulator the year before last but it went out before I was making around 20 volts instead of less. Also the tach is not working which is a sign of the rectifier but cannot find where it can make the voltage less rather than more? Anyone seen a rectifier reduce voltage rather than increase it or any other causes that could also result in tach failure?

 

[ONERCBOATER]

Re: voltage problem

the rectifiers only job is to turn AC electricity from the alternator (stator) into DC.... by its self it does a messy job of it, then the regulators job is to turn that into useful voltage.... a regulator can fail high or low, in my line of work (not outboards) I have seen regulator/rectifiers for PLC systems fail high and fail low, with low to just dead being more common.
you should be able to run the rectifier through a list of checks to determin if it is working properly, then at least you know part of it. if not in your manual, try a search on here, i know i just saw such a test described in detail.
if someone else chimes in with different or better advice take theirs over mine, as I am lil more than a shade tree mechanic.

Sean

 

[jvalhenson]

Re: voltage problem

thanks for the reply. Yea I know how to check the rectifier/regulator(per the manual of course which I seem to be referring to more and more very year I had just not been able to find anything indicating that it could fail low but i suspected that was it. Stator looks ok but I havent pulled the flywheel yet to really look at it and will be doing that tomorrow afternoon) and the failure of the Tach would also indicate a bad rectifier/regulator. Hopefully thats all it is(if not a loose wire or something I havent been able to put my hands on yet) and not both it and the stator. Both of them were bad year before last when I changed them both. At that time the rectifier/regulator had fail "up" as I said before and was making around 20V and when I pulled the flywheel 3 coils on the stator were burnt up. Not sure if the high voltage caused that or if that caused the regulator to go out or if they just both happened close together randomly but since they are part of the same system I figure one caused the other so hopefully thats not the case this time since they are both fairly high priced parts.

 

[ONERCBOATER]

Re: voltage problem

my stator went mildly south on my 1978 merc....I wound up replacing the wires right up to the coils and got away with out replacing it. I was actually prepared to rewind the lil bugger should it have failed as well... sigh having so lil money is annoying... not much time either but my time costs me much less than money. I hope it is a loose connection and all is well for you after tightening it.

Sean

 

[Lion hunter]

Re: voltage problem

This is just a guess as I have never had a motor with a regulator/rectifier unit. It may be one unit but it performs 2 functions. Rectifier turns AC to DC and the regulator..well regulates it. It is possible that just one of the functions go bad. You lose the regulator part and you could see high voltage. You lose the rectifier part you could see no voltage and no tach. On units with no regulator there is a very low voltage output. Anything above 12 (or above the standing voltage) is probably good. The units that have regulators tend to charge higher.

My guess is the rectifier function is bad and is not producing any voltage. If 11.7 volts is the standing voltage and it does not increase when running I would say your not charging and the rectifier is bad.

 

[Chris1956]

Re: voltage problem

You might check to see what you have. My '98 Johnny 150HPV6 has a water cooled regulator. I would be surprized if you have a rectifier in that motor.

Check for bad wiring from purple wire at ign switch to V/R as well as grey wire from V/R to tach.

The V/R test in the service manual involves putting a 35Amp load between the V/R and the battery to see what it will charge. You should be content to see 13+ Volts at the battery at fast idle.

 

[jvalhenson]

Re: voltage problem

yes it has a rectifier/regulator combo unit that is also water cooled....but it is 100% both rectifier and regulator...as stated before I just changed this about 2 years ago but at that time it had failed and was creating to much voltage(20) so I am thinking at that point it was the regulator componant that failed and this time it is the rectifier part that failed.....still have not had a chance to pull the fly wheel and get under there to check everything out so it very well could still be a loose or unplugged connection or a bad wire(hopefully anyways but as I sated earlier I have checked all the ones I can see without removing the flywheel and all but most are hidden.) Gonna be doing all that this week one evening so hopefully I can get it worked out pretty quick. One thing I did forget to mention is that twice the motor did seem to be affected by this(or something else) with weak spark or maybe a totally unrelated fuel issue. While running about 45 mph I felt and heard a slight change in the motor and dropped down to 40 mph and the motor just didnt sound quit right(could not tell exactly what the RPMs were doing since the tach is not working right now) but didnt sound or feel terrible so continued on another 3 miles or so to where we were going. Several hours later while running back in it did the same thing...just dropped about 5 mph off the speed and didnt sound quit right. Wasnt running rough or missing bad or anything like that....just dropped some MPH and didnt sound like her usual self. Still idled fine and cranked fine and all that. Fuel/water seperator was totally clear no water at all as was the inline filter. Ethanol gas is in the tank with startron fuel treatment added. Both times is did this I checked my voltage through my GPS and both times still had 12.2 volts showing. Yall think this could have been caused by a weak spark due to the "probably" failed rectifier/regulator or would showing 12.2 from the battery have kept that from happening or is it more likely that I have a fuel issue even though the filters are clear? Seems to me like just running on battery power could easily create a weak spark and drop the MPH slightly even though it was still showing 12 but as I have said in other threads pops is by far the better mechanic in the family and he is off in Tupelo working so on my own for the time being on this one

 

[jvalhenson]

Re: voltage problem

one thing after another........pulled the cowling off yesterday evening to check out a couple things and the dern thing that is glued onto the back of the cowling that has the post for the latch on it(dont know what its called but its the big hollow plastic piece) just fell off. Epoxy just let go....not a big deal.....just gotta clean it off, scuff it up and re-epoxy it back on but as if I didnt have enough to do on it already just one more thing to have to do before she can get back in the water.