Starter/gen starts, doesnt gen.

[Greentored 3,217]

Hope you all are doing well!  Ol Hoss the custom pooped a gen, I think?  Whirls the built, 9.3:1 K321 over like nothing, but 0v coming out of the arm terminal.  

New battery and correct regulator, grounds are all clean, wiring checks out fine (only a few years old). Took it apart and nothing jumps out at me except its a little dirty- even the brushes and springs look great. Arm and field continuity tests passed. 

While I dont have a TON of experience with starter/gens, my old Harley has had its share of gen issues over the years, and I always tested it by 'motoring' it- if it motored, all was functioning and it would charge.  Im stumped here fellas, any ideas?

[ebinmaine 69,812]

Hiya Scott!

 

There are bench test instructions for old tractors on youtube.

Do not use bench test instructions for a car because they don't use the SG for the S function.

 

Disconnect every wire and the belt on the front of it and follow that. If it bench tests okay, move forward to something like the regulator.

[peter lena 8,984]

@Greentored  found a lot behind dash areas , possible collective debris / hiding a wire chafe ?  probably hiding in plane sight  , pete

[ri702bill 8,769]

Did you have the battery disconnected for a while?? If so, you may need to polarize the generator. The current needs to be "taught" which direction to flow.

Does the ammeter flutter at Zero when running at idle ?? The current is waffling back & forth.

Look over the attached ancient Delco Remy files, complete with corny cartoon artwork... one goes over the polarization procedure.

 

Delco Remy IMG-150 Service Bulletin.pdf Delco Remy Regulator Manual 1R-116.pdf delco_remy_regulator_service 1R-111.pdf Delco-Remy SG Repair.pdf DELCO-REMY_SERVICE_BULLETIN.pdf

Edited February 18 by ri702bill

[Handy Don 13,109]

Definitely 

 

Those docs might need a couple passes to make clear sense because of the writing style but they impart a LOT of valuable and applicable information. 👍

[Achto 28,229]

17 minutes ago, ri702bill said:

If so, you may need to polarize the generator. The current needs to be "taught" which direction to flow.

 

This process is repeated every time that you start the engine.

[ebinmaine 69,812]

4 minutes ago, Achto said:

 

This process is repeated every time that you start the engine.

 

 

 

Agreed. If the engine is starting okay, polarization is correct.

[Achto 28,229]

To test the charging function of the S/G.

Connect a multi-meter to the battery. Disconnect the field wire from the S/G and connect a jump wire to the field terminal. Start the engine, touch the open end of your jump wire to ground. You should hear the engine labor a little and you should see your battery voltage increase.

 

If the above test gives you these results, then you have a bad connection or a bad regulator.

[ri702bill 8,769]

1 hour ago, Achto said:

This process is repeated every time that you start the engine.

Correct - once the initial polarization is established...

[Achto 28,229]

39 minutes ago, ri702bill said:

Correct - once the initial polarization is established.

 

To start your engine, you connect battery positive to the armature post on the S/G. There for you polarize the S/G every time that you start your engine. 

[pfrederi 18,200]

2 hours ago, Achto said:

 

To start your engine, you connect battery positive to the armature post on the S/G. There for you polarize the S/G every time that you start your engine. 

[953 nut 56,814]

This S/G manual should be all you need to figure it out.

 

[Greentored 3,217]

On 2/18/2025 at 10:36 AM, Achto said:

To test the charging function of the S/G.

Connect a multi-meter to the battery. Disconnect the field wire from the S/G and connect a jump wire to the field terminal. Start the engine, touch the open end of your jump wire to ground. You should hear the engine labor a little and you should see your battery voltage increase.

 

If the above test gives you these results, then you have a bad connection or a bad regulator.

I did this and get absolutely no laboring, voltage jumps, and zero volts out of the arm terminal. The thing acts completely dead but spins the engine over like its perfect.

Edited Thursday at 03:50 PM by Greentored

[Greentored 3,217]

Does the field even come into play during startup?

[pfrederi 18,200]

18 minutes ago, Greentored said:

Does the field even come into play during startup?

 

 

There are two windings...the start and the charge...the charge does assist the Start when cranking but the start does not assist the charge so your charge coil is probably bad.

 

 

Edited Thursday at 04:09 PM by pfrederi

[ebinmaine 69,812]