I have a 89 skeeter with a 70 hp mercury on it. The compression is as follows: #1-100, #2-120, #3-90. Would this motor be worthy of a rebuild. I might attempt this myself (average joe-not a mechanic). Any ideas what cause this to happen?? Do I need to buy a new or used motor? I'm fairly new to the boating world and this boat will satisfy until I get more experience on the water and try to buy a real nice boat.Please help.