I have a 1989 Malibu with the Mercruiser 5.7 Ski engine with 660 hours. I am the original owner. It overheated and stalled a month ago when the impeller fell apart. Been idling rough since. Did a full electrical tune up and that helped, but it still feels like it is missing at less than 1500 rpm. Plugs were not tight on the left front two cylinders. Checked the compression, 150 psi is spec, 145 psi on the 4 right cylinders. Starting from the rear on the left I got 140, 130, 30 and 60. Surprised it runs at all. Getting 4400 rpm at full throttle.
What is the most likely problem? I hope it is a head gasket, not valves or scored cylinders. Where should I start? Got tools. Any words of wisdom? What is the head bolt torque spec? I know that heads need to come off.
What is the most likely problem? I hope it is a head gasket, not valves or scored cylinders. Where should I start? Got tools. Any words of wisdom? What is the head bolt torque spec? I know that heads need to come off.