Briggs engine that "eats" ignition magnetos

Sirocco Jerry

Sirocco Jerry

Active member
A brand new trailer-system (built by others) was brought in to our service center last week..
.. engine wouldn't run.. NO spark at either magneto..
Tracing wires because the trailer-assembler had added a few things to the electrical..
I found a cut ground wire disallowing the "kill" function of the engine, so..
.. when he shuts off his key-switch, the engine hesitates to stop, as it "runs out of gas",
as the fuel-cut-solenoid closes vwith key switch OFF.
But now, the magnetos have quit, so we continue tracing wires..

Next, we found something a bit shocking..
The key switch terminal the charging system is connected to.. (the RED wire..)
..It is shorted to ground (the brown wire), when the key switch is turned to the "OFF" position..
That dumps a "dead short" across the charging system every time you turn off the engine !
Good thing the brown wire had been cut !?? .. NOpe..
The Magneto "kill" wire.. (the black wire..) is also shorted to groung, when the keyswitch is in the "OFF" position,
So.. in the case of a cut ground wire, or a "bad connection" to ground..
the Charging system is dumping a FULL load short-circuit to the MAGNETOS !!
..which killed both of them.

I figured the key switch was the wrong one, so I checked the parts book..
OMg.. it is the stock switch ! .. and the same wiring diagram as almost every v-twin Briggs out there !!

OK, so I could have wired the voltage regulator through the lighting terminal of the key-switch,
..which is NOT shorted to ground in the OFF position, but..
Why pass a 20 amp charging system through a 15 amp capable key switch anyway ??
..As long as the Voltage regulator is "good", it shouldn't leak the battery down with the system turned off.
..So I wired it directly to the B+ battery cable at the starter solenoid, with an ATO 25amp fuse.
Done..
With new magneto, and charging system separated from the magneto and Ingition switch.. all is good.

Moral to the story is this..
If you have a B & S V-twin,
Get that red wire pulled off the ign.switch, and run to the starter solenoid B+ terminal (with a fuse).
If you want to keep the regulator "isolated" from potentially draining your batter when stored for a long time..
Add a 70 or 80 amp relay.. E-mail me for details.

IF your engine "eats" magnetos.. check the ground connection, and move the regulator wire anyway.
If your engine "eats" Voltage Regulators.. same fix.

I'm calling Briggs in the morning to report these findings..
I'll report back here with their response.
 
Jerry,
We are running Vanguard engines (V-Twin). Is this the same motor?
 
Yes, that is a BIG problem if you are running Briggs. The best part is that the blame will be put on the contractor, every single time. Because, as we all know, it is always the contractors fault.
 
Kohler or Honda for me in gas motors. I have never had any luck with Briggs motors
 
Briggs V-twin system from us gets a FREE upgrade kit at $n/c

OK.. here's an update..
I talked with the master distributor for B & S..
the tech was shocked at what I found, and will be calling B & S this week for answers.
Plus, I looked at doccuments to find a hiding indicator, and I found one here..
It clearly shows the connection between terminals 1, 3 & 6 whilst #1 is grounded .. and switch in the OFF position..

B & S electr. V-twins.jpg

the older v-twin models have a metal mounting plate for the key switch,
which better-insured the ground connection, BUT..
The newer models, with plastic mounting, relying upon the ground WIRE (brown wire) for connection..
Those are GOing to be trouble, and trauma..
Until the RED wire is moved OFF the switch, to the B+ terminal of the starter solenoid.
..Just do it.
..and put an ATO type 20 or 25 amp fuse between that connection to protect the Voltage regulator.

Anyone that has EVER bought a Briggs V-twin system from us, can call us for a FREE upgrade kit at $n/c
I don't care if it was 10 years ago.
..that's the way we roll around here.
We aim to be your favorite supplier persistently,
even on a bad day.
 
the BIG V-twins all have the plastic panel, and the new 23's for sure.. I'll look at others this week.

Now guys, I don't want this thread to look or smell like a "roast"..
This situation is a bit shocking, but we've all made a few shockers along our way,
so what this is really about, is the test in "who does what" in th aftermath..

Knuckle-Heads in some blogs tent to "attack like dogs an go running down the street" without all the facts and learning experience..
This kind of situation is actually a "Mega-Trend":
In a community that has been trained for decades to "buy cheap",
us "old-school" guys will always have your back, IF you keep your composure, and pay attention, as we read between all the lines.

I have already made my recommendation (respectfully) to Briggs, and we'll see what comes of that,
but just because one manufacturer has to spend time cleaning mud off it's a$$ doesn't mean they were "all about deceit".

As a manufacturer that has sold thousands of systems, and in tandem run a very busy service center,
I can tell you there are things to like and dislike in all the engines made.
Example: 2 of the biggest mfrs in engines have ROAYALLY pissed me off for customer service skills.
neithr was Briggs, so I'm coaching this situation respecxfully, and for the BEST possible outcome to this community.
I found the problem, and I don't mind walking it through "the final score".
 
Sirocco Jerry said:
the BIG V-twins all have the plastic panel, and the new 23's for sure.. I'll look at others this week.

Now guys, I don't want this thread to look or smell like a "roast"..
This situation is a bit shocking, but we've all made a few shockers along our way,
so what this is really about, is the test in "who does what" in th aftermath..

Knuckle-Heads in some blogs tent to "attack like dogs an go running down the street" without all the facts and learning experience..
This kind of situation is actually a "Mega-Trend":
In a community that has been trained for decades to "buy cheap",
us "old-school" guys will always have your back, IF you keep your composure, and pay attention, as we read between all the lines.

I have already made my recommendation (respectfully) to Briggs, and we'll see what comes of that,
but just because one manufacturer has to spend time cleaning mud off it's a$$ doesn't mean they were "all about deceit".

As a manufacturer that has sold thousands of systems, and in tandem run a very busy service center,
I can tell you there are things to like and dislike in all the engines made.
Example: 2 of the biggest mfrs in engines have ROAYALLY pissed me off for customer service skills.
neithr was Briggs, so I'm coaching this situation respecxfully, and for the BEST possible outcome to this community.
I found the problem, and I don't mind walking it through "the final score".
Click to expand...
Jerry,
We thank you for doing just that.
 
Ok.. update..
Turns out there is a component in the Regulator that instantly cuts flow of electrons when the battery connection drops,
But..
I still don't condone working the entire charging system across the keyswitch.
..My suggestion to move the Regulator REDwire to the starter solenoid post stands.
But..
IF the regulator "craps-out" (that's the eletronics industry terminology. LOL) ..in a way that allows current flow,
and the ground wire is questionable.. you still zap the magnetos!
more soon.
 
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