Horn issue

[TMarsh]

I am currently working on a
sparton horn that is surely a reproduction. I put new brushes in and can not get the horn to sound correctly, it also stops during it's rotation. I have to give it a little help to get it to rotate. This is on my 1930 roadster. I also am having an issue with my
31 Budd cab truck. Same thing happening with the truck but I did not change brushes. I did notice, however, that the armatures turn opposite directions.
When viewed from the rear the roadster wants to turn counter clockwise and the truck wants to turn clockwise.
All this is with a fully charged 6 volt battery. Any suggestions as to getting these horns to operate correctly would be greatly appreciated.

I have tried adjusting the tension screw slowly in and out. When it works it sounds like a dying cow.

 

[Jim16A1]

Did you hook it directly to the battery? Maybe you have some corroded/weak connections that are making the horn see a big voltage drop.

 

[nkaminar]

Isn't a dying cow the correct sound?

 

[stevests]

For a Model T horn, it is - more like a sick calf !

 

[modelaer]

If it spins normally but doesn't sound right, the diaphragm may be cracked. It does not take much of a crack to be a problem.

 

[TMarsh]

Thanks for the input. Turns out the voltage was not sufficient with the motor not running. Works with motor voltage output. Probably not a good clean connection somewhere.