mini starter trouble

More info will help to sort this out:
- Did it spin the engine well before? I.e., aare these parts replacments or is the whole thing new?
- Is the battery well charged? Does its voltage measure 12.6-12.7 volts at rest?
- Does this happen even when the engine cold or just hot?
- How are the grounds to the engine and to the bell housing?

This could be:
- a simple battery charge problem or poor battery
- poor or corroded battery or starter connections
- poor ground connections to the engine or between the engine and bell housing