Slow to turnover the engine, Battery or Starter?

Bought a used car and it starts slowly with a little grinding in the morning espcially, gets better when warm. Had the battery tested twice at two different parts stores, it was declared good. Alternator was tested and also tested good.

So is it the starter that needs replacing? How can I tell short of paying $$ for a part I may not need?

Thnx

1997 J30t 140kmiles

Starter could be bad. Or you may have bad ground. It made a difference on my starter when I took some leftover 10 gauge ground wire and ran it from the battery's first ground point on the frame to the alternator and to the intake. Wire and crimp-on connectors are cheap. I'd give it a shot.

if that doesn't help and it is the starter, use it till it dies then replace it.

You can test a starter. Some parts stores have a good tester; usually on a cart, not the little handheld job. They can put an inductor clamp on the positive wire and test the amperage draw while you crank. If its too high, the starter is bad and should be replaced.

I also have a $5 amperage tester that I bought at Harbor Frieght. Its just a little analog gauge that you hold on the positive wire while you crank. The passing current can be magnetically measured by the meter. I don't konw if it works well, but it's a $5 amperage gauge that measures up to 250amps