Slow Starter Motor

[Jamonwholewheat]

I have done a full investigation yet but the starter on my 1989 Yamaha 90 hp 2-stroke is barely turning over. Never had the issue before, battery has plenty of charge, and electrical connections seem good. I also pulled the plugs to make sure the compression wasnt slowing it down, even with the plugs pulled it engages, turns once and then can't turn over again. Its acting as though the battery is low which was my first thought. I plan on going over all the connections tomorrow to check if that is the issue but was hoping to get some help before I start spinning my wheels. Here are a few questions I hope to have answers for before I begin:

1) Can I check the voltage and wattage received at the starter motor with a meter while attempting to crank the motor over?

2) What is the necessary voltage and amperage I should get at the starter?

3) If I have enough power to the starter does that lead to the assumption the starter is bad?

4) If I have a bad starter and wish to buy a replacement how do I find the correct replacement motor and where should I buy it online.

Hopefully I will get a few answers and hopefully its a quick and cheap fix. Thanks for the help in advance

[rodbolt17]

do a forum search.
keywords voltage drop test.

this has been extensively beat to death.

should be a sticky.

and quit using non universal terms.
yes there is a way to check current(amperage) with a shunt.
voltage is much easier.
testing wattage is a bit trickier due to the specialized nature of a watt meter.

[99yam40]

They make clamp around DC ampmeters that work well, but I have not seen anything listed for what the amp measurement would be. But I think it would be a high reading.
Like Rod said stick with voltage drop

Most of the problems ends up being battery, cable connections, or bad cables.
Cables can go bad internally, so do not rule that out.
Make sure you test + and - side

[throrope]

Screw the test. Replace the cables ASAP, especially the ground and use that terminal spray when done. Then move on to the next problem if it still exists. Keep in mind, if the starter's in trouble, the next one may face the same death if the original problem remains.