Home › Forum › Ask A Member › Merc 800 EL Stuck Engine › Re: Merc 800 EL Stuck Engine
Lay it on it’s forward side & spray into the cylinders & let soak. Usually what kills these motors would be a dirty fuel system, run them lean & score a piston & cylinder. Merc isn’t known for great fuel pumps. I would pull the crankcase as it needs new seals & bearings on the crank, then you can look for score marks in the cylinders without the strong-arm method. if you get it free check compression on them, should be 120 at the lowest & all within 10% of each other. They often blow the block to crankcase seal cause not using a torque wrench. They are a hi performance motor & everything with the timing & carbs synced to get them to run. Run your idle jets a little rich to avoid the bog. If you get one you can take apart without breaking at least a few studs, it’s a good day. They leak water from the exhaust covers on the block to rust things too.