Lighting Coil & Rectifier/Regulator - fundamentals

[IFish4Tuna]

Hello

I have a charging problem. It is not charging fully when I run for 40 mins at 3500RPM. It drops quickly (within 30 mins) to 11.6 volts w/ just the GPS, VHF, and live well. Batteries are new. That when battery selectors are on both. If I run port on 1 and starboard on 2, the house (2) is even less charged. You may have seen I commented in the other thread with similar subject with the image from my service manual. I am left very uncertain about next steps to diagnose. I have done all kinds of maintenance on this engine, but have not had to go deep into electrical. I am not following the method of test for lighting coil and don't want to blindly replace. I was under the impression the coil output AC voltage, yet the manual says 14V at 1500 and 3500 RPM. I'm a bit nervous about being electrocuted while testing under load.

So first question : Do I really need the test harness YB-06770 to perform this test? Maybe that's what prevents me from being electrocuted?

2nd question, do the above & below voltage specifications make sense in the tables, or is this page total garbage?

Any guidance welcome.

Service Manual image Charging.jpg

Ed

[Keithbaja]

Ummmm, 1st question ? You say it drops to 11.6 vdc in less than 30 mins. Holy s--t. Do U know how to test for current draw ? Is this after shutdown ? Remember a stator, alternator, charge coil, lightning, zapper, is NOT a battery charger !! They are to MAINTAIN state of charge around (hopefully) 12.7 to 13.3 vdc.. I would start with really checking your battery s and cables.... It takes 13.8 to charge a batt, 13.2 to float/maintain a charge. Next to Fish, Women, clouds, boats, gov, batteries and charging systems are the most understood units there are !

[IFish4Tuna]

Good morning. I hear you on women.

I had to move the boat into safer shelter this AM w/ the storm coming up and so I applied some test techniques read on historical threads on this board. I tested batteries before and after engine running (at idle).
BTW these are 1999 0x66 250HP twin enginenes. Group 31 batteries, 2 house 1 starter.

Battery	Battery Setting	Before Running	While Running
Starter	Both	12.8	13.2
House	Both	12.8	13.2
Starter	1	12.8	14.
House	2	12.8	12.8

I have been running the engines on Both for a while now. I guy has to fish ya know!

Anyway, now I'm on a mission to fix this. So back to my question. Do I need the test harness gizmo to test and maybe that gizmo converts the AC to DC?

I one of the historical message threads. This one : (https://www.yamahaoutboardparts.com/...coil-regulator)

boscoe99 said this :

I don't have a manual for your motor but for a 150 HPDI you measure the peak voltage from the lighting coil at cranking speed, 1500 RPM and 3500 RPM. Disconnect the connector and measure the two output wires from the lighting coil. 5.5 volts at idle, 37 volts at 1500 and 86 volts at 3500 RPM are the specified values.

and this :
The lighting coil is tested without being connected to the rectifier/regulator. It creates voltage whether it is connected or not. Actually, it being connected can affect its output voltage. Just like a battery will provide different voltages depending upon whether or not it is connected to a load or not. A battery is normally tested not connected to anything.

The rectifier/regulator on the other hand is tested while it is connected to the lighting coil, since it depends upon the lighting coil to do its job.

So I have not yet disconnected any wiring yet to examine the wiring harness connectors. But it looks like from the manual it says test the 2 green leads and look for 14 V while using the harness. So do I need the harness or can it be tested without safely? Also above Bosco is saying test for AC voltage, and manual is saying DC. Very confusing for me.....

Ed

[fairdeal]

you don't need the official test harness,
it just makes it easier to connect your meter.

but since you have twins and can easily swap the reg/rectifiers
thats the easiest, most obvious way to determine if an r/r is bad

What you have stated above is confusing,
you need to figure out/understand how the engine alternator power gets to the house load/battery

[99yam40]

you need the proper test equipment to read peak voltage to compare to the specs in manual

the voltage is not high enough to electrocute you unless you bypass the resistance of your skin by poking a hole thru it

I would think the 2 start batteries are tied together when set to both, if one goes bad both will be drained the house is not tied to the start batteries

and the house battery is tied to just one of the motor's axillary charging circuits.

the house battery runs your onboard equipment so it is the only thing being drained by them.

have you checked all of the battery voltages at the batteries when you get the 11v reading show up on the gauges?

[IFish4Tuna]

It's actually the 2 house are tied together (stargboard side) and the start single battery is (port side). According to my grady manual. I should have my battery switches set for port on #1 and starboard on #2 to charge respectively and to avoid inadvertent drain of all 3. If I chose both it means they are all linked together for charging and draining. I can no longer drive/fish with the battery switches set to 1 & 2 respectively because the house gets no charge. So I drive on both, then when at anchor fishing I change to 1 & 2 so I don't drain the starting, but the charge capacity of just 1 engine is not enough to get the batteries fully charged. I may just buy the new coil instead of F'ing around w/ testing. it's a 20 year old boat. I just figured someone had already done this test and could tell me how they did it without trying to find the test harness and killing them self

[boscoe99]

Out of the ordinary configuration. Usually there is one start battery for each motor. Then one or more house batteries.

Start batteries get charged by the battery cables. House batteries get charged by either a Yamaha isolator lead or a VSR/ACR/Combiner between the start battery and the house battery(s).

Without a wiring diagram as to how your batteries are wired to the motor it is difficult for me to understand what is going on.

[boscoe99]

Typical modus operandi it to check the R/R output to the battery. Should be nominally 14.5 DC volts. If voltage is low then test the lighting coil.

If lighting coil does not come up to specification, change the lighting coil. If the lighting coil is up to specification, change the R/R.

[boscoe99]

Ummmm, 1st question ? You say it drops to 11.6 vdc in less than 30 mins. Holy s--t. Do U know how to test for current draw ? Is this after shutdown ? Remember a stator, alternator, charge coil, lightning, zapper, is NOT a battery charger !! They are to MAINTAIN state of charge around (hopefully) 12.7 to 13.3 vdc.. I would start with really checking your battery s and cables.... It takes 13.8 to charge a batt, 13.2 to float/maintain a charge. Next to Fish, Women, clouds, boats, gov, batteries and charging systems are the most understood units there are !

From where did you come up with this logic?

If a battery is used to start a motor it gets charged by the electrical generation system.

If the battery is used to run a live well pump, operate a trim/tilt motor, run graphs, or run anything else in the boat it is the job of the electrical generation system to charge the battery.

To MAINTAIN a state of charge only a few amps are needed. Most Yams have much more current output capability than providing a few amps of current. More and more so as the motors and boats get bigger and bigger.

I certainly agree with your comment about electrical generation systems being most understood.

[IFish4Tuna]

BatteryLayout.JPG





Hi - attached is my battery configuration. I would like to test the stator and the R/R, but the steps of how to is what has me confused.
After disconnecting the Am I testing the green leads 1-2, 2-3, 1-3 coming from the stator at the different RPMs?

Am I looking for 14V like the book says, or am I looking for 150V like common sense says? I assume the later.

I assume I'm looking for 14V coming out of the R/R since that's what the properly charging battery reads when engine is running.

[99yam40]

why would you think 150V would be on that if the specs do not say that?

[IFish4Tuna]

BatterySelector.JPG

[IFish4Tuna]

ChargingCoil.JPG

why would you think 150V would be on that if the specs do not say that?

I had read in another section in the ignition section related to charge coil. But charge coil may not be same as lighting coil. As you can see I'm guessing here.

[99yam40]

yep charge coils have nothing to do with the lighting coil that furnishes the battery voltage

[boscoe99]

What model motors?