76 Volvo penta aq130d/280 overheating

[S3xyone]

Hello everyone. We have a Volvo penta aq130d/280 and the first time we took it out it overheated. I have put the "muffs" on it. and I have taken the water line to the water pump off. and there is no water getting to the motor. from my research, people have told me to check the raw water pump. my question is where do i look to find the raw water pump and how do i know what to look for to determine if it is good or not. also is it easy to change myself or is it something tat a mechanic has to do? is there any way to test the raw water pump? what must i do to find out if this the problem? plz help as i am getting very frustrated and we would like to use the boat this weekend. also on the top of the leg when the leg is down there is a large alan key plug, is there supposed to be some kind of oil in there, if so does anyone know what type of oil? when the leg is up this plug is not visible.