1995 40hp tracker/merc over charging problem

[JonNovak]

have a 1995 tracker with 1995 mercury 40hp. boat was charging cranking battery over 16 volts on and off last 2 times i had it out (december 2018). Those were the first 2 times ive had it out since buying it last summer. i put a new rectifier on it and this time it charged fine for first run. second run it over charges. third time, and all the following runs it seemed to not charge cranking battery at all or very little. 12.7 was all i got on final run.
I have an almost entire spare motor minus bottom end and compression in one cylinder i can rape. rectifier in that motor didnt look all that great either so i sprung for a new one. Im not sure what i should check first so im open to hearing from you. Honestly rather have it not charging or low charging than keep over charging.

[Avanti]

I have a 1997 Mercury 40 hp, it started charging the battery at 17 v. Removed the regulator and I could see it was burned.
Replaced it and got good charging voltages.
Since, I had an instance where the charging voltage was in the 12 - 13 volt range which was too low.
I removed the regulator, which looked ok, and re-installed it.
I charged my battery with an external charger.
After that, the charging voltage was in the 13 - 14 volt range.
So, I would try charging your battery and see what happens after that.
I have an external CPS module with a console power switch. Burns 800 ma.
If I forget to turn that switch off for week, my battery can get pretty low.

[JOE54]

was oem regulator used as replacement ,need ser num to look at charging system

[JonNovak]

I have an onboard charger to charge all three batteries and battery is 3 trips old. tests and works great, but not for long if i run 16-17 volts charging while running.

anyways, tested all 3 rectifiers and all are dead. 2 are oem, one is off 95 motor and one is off 96 motor, both 40hp. new rectifier was probably from china. shipped from cali and ive learned they sell china crap from there and new york. ill be getting a price for new one at west marine and compare to cdi, and compare warrenties.
will also be replacing one end of my 2 yellow wires since one looks a little burnt compared to the other bullet connector.

[JOE54]

correct batt/non deep cycle troller

[JonNovak]

cranking battery is from batteries plus bulbs. biggest heaviest heavy duty battery i could get
trolling motor has its own batteries not connected to anything else.
i got a refund already from ebay rectifier
any suggestions on what/where i should buy new rectifier with any kind of warranty. Going to try west marine this afternoon find out details

[CatFan]

cranking battery is from batteries plus bulbs. biggest heaviest heavy duty battery i could get
trolling motor has its own batteries not connected to anything else.
i got a refund already from ebay rectifier
any suggestions on what/where i should buy new rectifier with any kind of warranty. Going to try west marine this afternoon find out details

Best place to buy it is from somebody who sells Quicksilver products.

One thing to keep in mind is that when seeing low voltages is that it may not be because of a regulator issue. Particularly with a small outboard and a large battery, a discharged battery may present enough load to the charging system that it simply can't raise the voltage to a normal charging voltage.

Another thing is that using a large battery may open you up to problems with your charging system. The charging system wasn't designed to handle the load of the equipment in a modern boat. It's essentially there to recharge the outboard battery after cranking and not much else. When using a large battery, you'll need to closely watch charging system status and regularly inspect your regulator for signs of overheating that could warn you of an upcoming failure.

[JonNovak]

Ive had the same cranking battery on my other boat last 2 years. its just a heavy duty 29 or 31 size battery. ill have to post back with what it actually is.

[JonNovak]

cranking battery is duracell ultra SLI31sa

My butt hurts. Just got the premium geniune sierra 18-5743 regulator from west marine and paid the premium price.
it doesnt say anything about being a rectifier. it says "For: Mercury engines with 16 amp or 40 amp charging system model/years 1992 to present"

i assume its a rectifier since it connects to the 2 yellow wires and accepts the input from stator. does it sound like they gave me the correct part? How do i know if my motor is 16 or 40amp charging system?

both old parts have numbers in ink on them 815279-3 (2395) and 815279-4 (1296)
they also come up as regulators and seems the (2395) and (1296) may indicate years produced

[JonNovak]

serial numbers are
original motor 1995 0G237930
1996 parts motor 0G313277

when i got the boat the 1996 was on it and used but had no compression in bottom cylinder. the original motor was half taken apart. i didnt get a real reason why. i was planning to sell them both and go maxed out but that got side tracked. i put the original motor back together and compression checked out good. so i took bottom end off the parts motor that was on the boat and put it on the original motor. supposedly the bottom end was out getting rebuilt. supposedly the original motor had head gasket done or something. all the info was a little confusing.
3 times ive had it out and its run great (granted its a little slow). few hiccups though. 12p prop way WAY wrong. BPS looked up and it was supposed to be 14p. all i could find locally was 15p and runs around 6000 rpm with 2 guys and hardly any fishing equipment. only been in the river and striper fishing so dont carry much.
also, the buzzer problems. disconnect oil tank and temp sensor and buzzer still is not normal. sometimes didnt turn off. so i took the buzzer out. now im switching the oil level module from the parts motor. the buzzer was in the boat, and i suspect he didnt have buzzer problems or else he probably would have cut the buzzer out, i suspect.
so im gonna try switching the module and put the buzzer on bullet connects so i can troubleshoot it as i go. I tested the oil tank sensor back when i put it all together and both tanks sensors are good. I rebuilt the entire boat last summer/fall. everything was removed, replaced and refurbished rebuilt. the only thing i didnt remove was the livewell.
was planning to speed it up and have some toying around days in the summer with the kids and grand kids

[JonNovak]

20180901_095444.jpg

20181215_083355.jpg

[CatFan]

cranking battery is duracell ultra SLI31sa

My butt hurts. Just got the premium geniune sierra 18-5743 regulator from west marine and paid the premium price.
it doesnt say anything about being a rectifier. it says "For: Mercury engines with 16 amp or 40 amp charging system model/years 1992 to present"

i assume its a rectifier since it connects to the 2 yellow wires and accepts the input from stator. does it sound like they gave me the correct part? How do i know if my motor is 16 or 40amp charging system?

both old parts have numbers in ink on them 815279-3 (2395) and 815279-4 (1296)
they also come up as regulators and seems the (2395) and (1296) may indicate years produced

Sierra isn’t genuine anything.

[JonNovak]

its a genuine sierra brand, no?
its not mass imported no name junk all over ebay. you saying i should toss it in the trash and start all over?

[JOE54]

oem newest number is 8m0084173

[JonNovak]

So second trip with new rectifier and same result as previous trip.
fully charged batteries when firing up for first run, charges at 14.2 volt. second run same, third run charges at 13 something volt. then all following runs seems to charge really hardly at all. im at 12.6 volts and it will creep up a few volts before shutting off motor.

I pulled stator off parts motor and will test. then possibly off motor on boat and test. maybe something wrong.

any ideas?

Good that buzzer is fixed. Fixed over temp sensor with solder and swapped low oil level module. buzzer works normally now

[JonNovak]

stator resistance all out of wack. stator on parts motor was all good. hopefully fixed charging and probably run better.

[JOE54]

good deal glad you found the problem

[JonNovak]

had boat out yesterday. seemed to charge much better. 14.2 volts most of the runs early until graphs and starting drained battery down to low 12 volts after about 8 hours on the water. then it seemed to show mid 13 volts during later runs on graphs and console gauge. does that sound more normal?

[CatFan]

had boat out yesterday. seemed to charge much better. 14.2 volts most of the runs early until graphs and starting drained battery down to low 12 volts after about 8 hours on the water. then it seemed to show mid 13 volts during later runs on graphs and console gauge. does that sound more normal?

That sounds fairly reasonable, but it’s telling you that you are really discharging the battery during the day.

[JOE54]

agree