I have a Speed Queen Marathon washing machine (Model NA3511).

The washing machine fills VERY slowly, especially with hot water.

Hot water (at full-strength) comes of the hot-water hose.
Cold water (at full-strength) comes out of the cold-water hose.
The screens at the water inlet valve are clean.
The water inlet valve is OK (tested with a volt-ohm meter).

What other parts should I check (and how do I test them)?

The washer has:

a large dial to select the wash-cycle and duration of each cycle
a dial to select the water-level (for large, medium and small
loads)
a dial to select the water-temperature (hot, warm or cold).