I only have one voltage regulator, should there be two?

[eh2000]

Engine Serial number 0G981368
2000 Mercury Promax 225
Not sure on exact make or pitch of prop, it is a stainless 4 blade with no markings on the barrel, it does have four holes and EOT-14326-R4 marked inside the barrel.
Maximum RPM is unknown at the time because I haven't learned how to drive the boat at WOT and I'm still setting up engine height. At 60 MPH the chine walk starts and I'm still learning to correct it. The RPM is around 5000 at this point.
Idle water pressure is 4-5 PSI and at 5000 RPM it is around 18, unknown what it will be at when at full WOT as mentioned above.
Analog instrumentation installed in the dash.
No engine mods that I'm aware of, but some things aren't adding up.
The boat is a 1993 Bullet 20XD that I bought used a few months ago.

My engine quits while running. It does not surge, just stops. I can immediately restart the engine and continue running. Interestingly, I can also start my engine in gear. No warning beeps or horns, but there also isn't a beep when I turn the key.

After searching BBC and the internet at large I have concluded I need to inspect the fuel delivery system and the voltage regulators to correct the dying problem and possibly have the ECU tested. Tomorrow I will do some more troubleshooting for a more complete understanding of the condition of this engine, but for now I have discovered that I have burned wires on my voltage regulator (singular). I have read multiple posts that indicate voltage regulators (plural). After using the link to search for parts at European Marine Parts I am not sure if I should have one or two voltage regulators. One would seem to indicate a 16 amp charging systems and two would seem to indicate a 40 amp charging system (2x20 amps systems together)? The stator does not look burned, but I have also not tested it yet.

I am far from an expert and really just trying to piece together what I've read from multiple searches of multiple forums and YouTube.

Attached below is a picture of my voltage regulator and the plate it mounts to, which seems to clearly show a place for two.

If anyone has a guess as to why I only have one or reasonable suspicion on why I might only have one from the factory, I would appreciate it.

[Merc2.4]

Ya it's missing a regulator. Not sure how they have this wired in but u suppose have 2. Also if its burned , just matter of time b4 u have urself a fire. Get ahold of don and get 2 regulators

[jeffblanton]

If anyone has a guess as to why I only have one or reasonable suspicion on why I might only have one from the factory, I would appreciate it.

That is not a factory regulator.

[revlimiter]

Take a picture with the flywheel cover off and the wires going from stator to regulator, they may have put a 16a on it, maybe. Does engine stop at idle or when running down the lake? If it is a 40a with one regulator it could be shutting down on overvoltage.

One thing about these motors is they’re old and lotsa parts are interchangeable, so you never know what you’re gonna find. I know of a promax that’s a combination of at least 6 different engines.

[EuropeanAM]

Take a picture with the flywheel cover off and the wires going from stator to regulator, they may have put a 16a on it, maybe. Does engine stop at idle or when running down the lake? If it is a 40a with one regulator it could be shutting down on overvoltage.

One thing about these motors is they’re old and lotsa parts are interchangeable, so you never know what you’re gonna find. I know of a promax that’s a combination of at least 6 different engines.

+1

Keep in mind, unless someone has "spliced" wiring, even a 40a Stator would be unable to pass charging current on the second winding set (it passes through the regulator to get to the battery).

40a Stator will have TWO PAIRS of Yellow Wires (whereas the 16a will have one only one pair).

[eh2000]

Thank you for the help ya'll.

Merc2.4, I wholeheartedly agree this is a fire waiting to happen, only exasperated by the small scale fuel leak from the output connection of the primer ball. The yellow wires of the single voltage regulator look terrible. I am looking forward to identifying the proper part and replacing this faulty one as well as a significant portion of the fuel delivery system.

revlimiter, the engine stops when running on the river. It has not stopped during idle yet and I have not done enough testing to find out which RPM range is stops at. Mostly because I am concerned with it bursting into flames at any moment due to the condition of the voltage regulator wires.

EuropeanAM, I don't see any evidence of spliced wiring. Based on the other "custom" wiring I found throughout the boat, if it was done by the same previous owner it would be very easy to spot and would look terrible due to copious amounts of cheap electrical tape and T-taps. The wiring under the stator and to the voltage regulator looks good, minus the black goo among the yellow wires and associated bullet connectors, which ostensibly will be where the fire starts if left uncorrected.

Here is some updated information to aid in troubleshooting and diagnosis. Some of this is unrelated to the voltage regulator problem, but will help to understand the state of this engine.

Fuel pressure prior to cold start is 36 psi. As the engine is warming up the pressure is 34 psi. After warming up for 5 minutes I observed the fuel pressure gauge for 1 minute; the pressure started at 31 psi and stayed for a full minute. I'm sure a longer test would be useful for further diagnosis of the fuel system, but that's all I had time for today.

Compression test after the 5 minute warm up indicated the following. 106, 107, 94, 83, 88, 86. I could have easily done this wrong so I will further review how to conduct a compression test and then repeat later.

Cranking battery voltage without the motor running was 12.88. With the engine running it was 12.49. During an acceleration onto plane it maxed out at 12.80, but I have to admit I was splitting my attention between driving the boat and watching the multimeter.

Attached are the requested photos of the flywheel, the part number of which is 74787. The part number for a 2000 Mercury Promax 225 with my serial number range is 859238T8 according to the parts database at European Marine. Hopefully these are the sections needed to identify the type of stator and/or flywheel I have, and then the resulting proper voltage regulator.

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[kls2020]

Since this motor is on a Bullet..... It is common for "Go Fast " guys to use a 16 amp charging system instead of a stock 40A ? for less load on the engine to try to get higher engine rpms for a little more speed . You can't run a 40 amp flywheel with a 16 amps charging system so that needs to be verified first thing . If your Voltage regulator is failing it can put "Noisy" AC signals to your battery system and wreak havoc with electronics such as your EFI system's ECU . With a fully charged battery your motor should start/ run and battery will slowly discharge with the voltage regulator disconnected . Just make sure the ends of the disconnected stator wires are well insulated with electrical tape .This will allow you to determine if the volt reg is the source of your sudden shut down issue . Just be careful till you figure out driving your new boat .

[eh2000]

kls2020, I’m not sure if this is common, but I have read a bit about it. Something to do with less stress on the top bearing at high RPM. I wouldn’t be surprised if this motor revs a bit past 7000.

Below is a picture of the connections from the Stator to the Voltage Regulator. Since it is in need of replacement I was hoping to find an appropriate OEM part number and then resume the troubleshooting. However, if this proves too difficult I’ll just order a replacement for what is installed now.

What damage would result from running the engine without the Stator connected to a Voltage Regulator?

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[eh2000]

Does anyone know how to confirm what the most current version of an equivalent Mercury Voltage Regulator is?

My searching has lead me to believe I could order a Mercury Quicksilver Reg Kit-voltage 815279a, but this part number has -1 through -5 associated with it from what I can tell. Does Mercury have a tech support line that would understand my situation of having a nonstandard Flywheel/Stator?

It’s either that or order a CDI 194-5279 as I know it works to some degree.

[leonreno]

Usually the number on the end is the “version” number, as in a5 is the newer and updated version of the a1. Always best to use the latest version. Call European Marine on the phone to get the best part for your motor. They should be able to find what is best for your frankenmotor.

[kls2020]

Here is some info I found online for the Volt reg you have with cross reference #s .
I think both red wires out of your regulator should both be connected but from your picture it appears only one red wire is being used . No damage should occur by isolating the yellow wires from the stator ( = Open Circuited ) as long as the don't short together with engine running . Tape up good .

Mercury Voltage Regulator by CDIFor Mercury Engines with 16amp to 40amp charging system. Model years 1992 to present.Replaces:

• Mercury - 815279A 2, 815279A 3, 830179A 2, 830179A 3, 883071A 1, 883072T, 8M0084173

[eh2000]

leonreno, thanks, I might get Frankenmotor decals put on it. I like that.
kls2020, thank you Sir.

[EuropeanAM]

Use Mercury Part# 8M0084173 ONLY. Avoid aftermarket stuff- and you will need to replace the harness/stator side Bullet Connectors (where melted, burnt, blackened, browned or otherwise compromised).

Does appear that you have a 16 amp setup.

Might want to check closely, but one of those pictures "looked" like the top crank seal might have been leaking recently.

Recheck voltage at that point... and see where you are at.

[eh2000]

EuropeanAM, thanks for the part number, that’s very helpful. Which photo looks like a leak?

Does anyone see any reason to use the bullet connectors instead of a Anchor butt connector with heat shrink adhesive and crimped with a ratcheting crimper? Seems like when these fail they toast the wires and connectors.

[EuropeanAM]

First 3 pictures.

Do NOT use other connectors. If you order that regulator from our Parts Department, they keep the OEM Bullet Connectors on hand (and can sell them to you based on your count of "x number Female" and "x number Male". The Regulator already has new ones on the regulator side.

Hope this helps!

[eh2000]

EuropeanAM, I will inspect those areas for any sort of leak, good looking out.

Can you expand on how the bullet connectors are superior to a proper marine grade butt connector with adhesive heat shrink?

[EuropeanAM]

Clamp load of the bullet connectors (both at the crimp AND at the bullet) is essentially a full-round clamp load of the connection (as compared to a "smash and clamp" or "jab and clamp" method used by most generic electrical crimp connectors).

Additionally: If you "cut, strip and crimp" the ends of a brand-new regulator, you have just modified that product and essentially ended it's 1-year Warranty (before it ever went into use).

[eh2000]

EuropeanAM, thank you for your opinion on this subject.

[Merc2.4]

And I agree that's a 16amp flywheel that sumone using a regulator on it. If it were me. I'd stay with 16amp and use rectifier like they came from merc , or go back to 40 with dual regulators. Jmo
Also alot cheaper for rectifier than regulator

[eh2000]

Merc2.4, do you have a part number for a rectifier?