I have a 84 Merc 4 IL 75 HP. Compression 136, 100, 110, 115. Getting some aluminum throw off on clyn 2. Timing 4 deg at TDC at idle, 36 deg at full. Idled great, but then started monkeying around with spark stop. Then more problems started. Now it will not start. Finally gave up and took it to a shop. They did a compression check and got 150/120/60/140. I can't understand why my compression went down so fast on clynder 4 and up on clynder 2. They also stated that they found signs of water on plugs. (I believe that, as I also saw when I pulled the plugs prior to taking it to them) On their notes they state they removed the head and fnd GSC brown and major scarring on cly walls. They did an estimate for 1 power head, 4 carb kits, 1 w/p kit. I know that I don't know much, but I believe that there is only 2 carbs, so why would they new 4 carb kits? What is a w/p kit (waterpump?) So after $150 later, I still don't know what to do. I believe when they stated they removed the Head, I'm assuming that it was the water jacket. As I saw pieces of the gasket sitting in my boat. I've looked at getting a new motor, but can't seem to part with green. So I'm thinking about rebuilding it myself. I don't have any experience with motors, but am pretty technical. I would love to learn the hows of rebuilding this. Any recommendations on first place to start? I have the clymer manual, but would the Seloc manual be better? Should I remove the water jacket and inspect the walls? Thanks for your expert help.<br /><br />Looks like Salmon season will be over for this year, until I get this thing runnin. 
