I have a H-37. When I bought it, a birds nest was in the hole for the tachometer. I found a used Yanmar tach at a used equipment store in Florida. I brought it home and stuck it in but now need to know what wires go where from my Yanmar engine. I don't have the sending unit in my engine but would purchase one if I knew how to hook it up. I understand that you can simply hook it to the alternator but, I need to know how. Can anyone help me out?