@Jkirkendall91
First... Welcome to the forum. You are already getting a handle on how to use it. Ask questions, look at the responses, try one or two of them then come back with results. Pictures help to clarify your observations of a problem. Sometime we see more in the image then you are describing.
You are starting at the easiest end to address the problem. Water must come out the exhaust to keep your engine cool. So starting at the beginning (where water goes in) is a very good place.
The strainer. Is it above the water level or below. If below you can open it up and water should come flowing out.
If above the water line then the engine pump will need to draw water in to the strainer.
Follow the lines and with the thru hull cracked a bit open see if water is available all the way to the engine water pump. Here we are checking to assure the lines are clear.
Next, with the thru hull closed, open the raw water pump. Should be 4 screws in the face cover. You will know the pump because you have traced the hoses from the thru hull pass the strainer to the pump. Open the face cover and inspect the raw water impeller. It should look something like this.
or this
If you see any of the vanes cracked or missing you have found your problem. These should be checked and often changed yearly. You will need to identify your pump and get the proper "Impeller" to fit. You will want to have a spare on the boat.
SO get a new one for your engine and then do the inspection. You may find a new looking one in your boat. and the new one you just bought is now the spare. You may find it looks something like this...
no there is your problem.
Here is a service link that my help.
https://www.westmarine.com/WestAdvisor/Impeller-Replacement-101