Briggs & Stratton 4Kva diesel genny - common transformer faults?

[Nomad]

As the title, I've been offered a faulty B&S genny, owner put it aside 3 years ago when "the transformer broke" and is now selling it off to make space.

Does anyone know if theses are fixable? I'm happy swapping boards etc if I can get the parts, or repairing circuit boards at component level but have no idea what's inside of these - or if they are even repairable.
Comments / ideas / usful info would be appreciated
What's a fixer-upper like this worth? Owner is asking for offers and I have no idea what's reasonable.

 

[The_Yellow_Ardvark]

Depends on what’s wrong with the transformer.
Some had a fusible link in the output side.
Some had a link on the pcb.
A resistance check should confirm if the coil are ok.

If it is cheep enough, at the worse you will have a spare engine.

 

[Agroshield]

His description of the transformer is slightly misleading as there is no transformer inside it. The engine is connected to an alternator.

If there is no juice from it, either the alternator windings are kapput or the control circuitry downstream of them is broken. If you can start it and find the wires coming from the alternator, like TYA says, putting your tongue across them will confirm or deny the first possiblity.

Alternators can be rewound, but it may be cost prohibitive - so ask a rewinder for a ball park figure.

There is not a lot of info. about them online. Jack's Small Engines (US) seems to have some stuff. If searching, you need to write prodiesel (no space betreen pro and diesel).

 

[Seadog]

Diode pack in the alternator possibly O/C.

 

[Robotstar5]

There are a couple of good FB groups such as this one that may be worth asking on.

 

[voipio]

It could be there is insufficient residual magnetism in the alterator to get the exciter field up and running.

 

[reb78]

It could be there is insufficient residual magnetism in the alterator to get the exciter field up and running.

I had this. I connected an electric drill to the plug with the engine running. Pull the trigger and spin the chuck carefully by hand - this seemed to get it going. DONT grab the chuck as if this works it will get the alternator working and the drill will turn under its own electrical power so if you are holding it, it will hurt!

 

[Nomad]

Thanks everyone, I'm waiting to hear back from the seller, will let you know what happens

 

[Nomad]

Update is he is asking for offers around £250 as the price new is/was north of £1,700. Engine was working when it got put away, he’s not tried to start it since.

Electric start, commercial kit but not 3 phase. Spec in the last column of the screenshot.

 

[the snooper]

Think id want to know more about it first, what type it is, does it have an avr as that could be blown, could be capacitor, diodes, windings so may need a full new alternator, I personally wouldn't pay that for a broken genny of that size

 

[the snooper]

 

[not done it yet]

It could be there is insufficient residual magnetism in the alterator to get the exciter field up and running.

Often caused by leaving the power connected, when stopping the unit. Running out of fuel used to be a regular reason…

If the stator windings are toast, it is likely an uneconomic repair. Most other faults can be sorted.