I have a 83 240d motor in my garage and I have the starter connected to the engine. The tranny is off the motor. I want to test the compression on the motor. I have a battery with plenty of juice.

There are 3 electrical connections to the starter. 2 are large and 1 small. There is 1 large connection closer to the top of the engine and another large connection that is toward the bottom with a metal strap going into the starter.

I want to attach jumper cables to the starter and then touch the cable to the battery to have the engine turn over.

I connected the negative to the larger terminal closer to the bottom with the strap going into the starter. I connected the positive to the small connection that has a screw going into the starter.

I didn't touch the large connection closer to the top because nothing happened when I did.

With this configuration, the starter engages but does not rotate the engine. The engine is not seized.

Can anyone help with where the negative and positive should be connected?

Thx.

pete