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Bit of a silly question about B&S engines.

I know this is a UK news group, so this may well be OT. I can only hope you will forgive me for posting questions about an American made engine.

Does anyone here know about Briggs and Stratton engines?

I recently changed engines in our ride-on mower.

It had a 12.5 hp and I swapped it for a 13 hp (it used more oil than petrol! (-: ).

It goes well but my original motor had two wires coming out of the alternator (under the flywheel), which plugged into the wiring loom. The 13 hp has only one, and it doesn't seem to have any current when tested with a multi-tester while the motor is going.

Which means the battery isn't getting any charge. Being a magneto ignition this doesn't effect the running of the motor, but since it's electric start only, well as you can guess, I have to charge the battery at night.

Any help however small, will be greatly appreciated.

-Max (down under) Xam = Max -- I had dinner with my father last night, and made a classic .Freudian slip I meant to say "please pass the salt" but it came out, ..."You prick you ruined my childhood"

-- Netscape>Mozilla Suite>Seamonkey A blatant plug for the latest offering in a fine tradition.

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Reply to
Xam
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Have you not found google.com? The B&S web site is easy to find and has the manuals for their engines available for download.

Reply to
Dave Liquorice

A couple of thoughts come to mind. I'm assuming the engine is second hand.

The wire you've found is for an ignition switch and is used to stop the engine by connecting it to earth.

The second wire is broken behind the flywheel.

The engine doesn't have a generator even though it's got an electric start. In it's previous application, whatever it drove may have charged the battery.

John

Reply to
John

i suspect the two wires were the coil for the charging devices. you'll find about 22 volts AC on them when the engine is running. the single wire on the new engine may be another coil for charging or it may be to a kill switch to stop the engine. did you check for AC? just past experience..... sam

Reply to
SAMMMM

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Just change region/language to your area. Input your engine number to find manuals etc. Is there a parts diagram there to show what your engine has/had, might be a good place to start. HTH Anthony

Reply to
Anthony

Hi Dave, thanks for your reply.

I had already done as you said, and even printed out hard copies. I even have the full workshop manual (on CD) for all B&S motors from 1981 onwards. As well as a hard copy of the manual for the mower it's self (from their website). So I did do my home work before asking for help here.

Unfortunately, there are four alternator coils listed, with no indication as to which engine, each is in, (I would guess they are interchangeable) or the difference between applications.

They are: DC only. Dual Circuit. Tri Circuit.

10/16 Amp.

Looking at the plugs, my old one had either a dual circuit or a 10/16 amp. The new one looks to have either one of the other two.

-Max

Reply to
Xam

Thanks for your thoughts John.

Yes the engine is second hand. It's last application was also in a ride-on mower.

All these B&S engines have a wire that's dedicated to stopping the engine, connected to a bracket off the side of the carburettor. When the throttle is moved to the stop position, it earth's out the magneto.

That wire is all present and accounted for. It doesn't come from under the flywheel (where the generator coils are situated), but from the externally mounted magneto coil.

I will have a closer look as you suggest, to see if I can in fact find another broken wire.

-Max

Reply to
Xam

Hi Sam, thanks for taking the time to reply.

I did check for AC as well as DC current, both settings produced zilch output, and unfortunately I can't test the output of the wires from the old engine. Well, not without building a test bench and swapping over lots of parts anyway.

I haven't tried earthing out the single wire on the new engine to see if the engine stops though. As you would understand, I was a little reluctant to try that one, as a dead short may burn out the coil windings. (-:

-Max

Reply to
Xam

Thanks for the link Anthony.

I have the correct manuals and parts lists for these engines, from the B&S website as it happens. Funny enough, they are the same ones for both engines. I think all they did was increase the size of the bore slightly in the 12.5Hp for the 13Hp version (or vice versa, not sure which came first).

Anyway the numbers are:

13HP: Model: 286707 Type: 4528

12.5Hp: Model: 286707 Type: 4028

The four types of alternator coils are all illustrated in the 'Parts List", otherwise, there is no other mention of them anywhere I can find.

474 696578 Alternator (DC Only) 474A 696459 Alternator (Dual Circuit) 474B 696457 Alternator (Tri Circuit) 474C 696458 Alternator (10/16 Amp)

The only other thing I can think of, is to beg, borrow, steal, or fabricate (the most likely) a flywheel puller, and change the alternator coils over.

One of the wires going into the wiring loom appears to go to the headlight switch. Needless to say, that one is of no concern. The other however goes to one side of the amp meter. This is the one I would assume has to do with charging the battery.

You know the thing that really makes me think these engines are smeg, is the fact that they have no big-end bearing shells.

Oh well, thanks for all the help everyone. I really do appreciate it.

-Max

Reply to
Xam

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