1991 5.7l Ski Bluewater (Chevy 350) in a Malibu euroF3 195 skier.
At over 2000 RPM, only under load, the engine produces a rattling/knocking sort of sound and produces less power than normal. Was working well at the end of the last season.
The sound seems to come from the right side (even numbered cylinders).
We removed the exhaust manifold on the right side to check for any exhaust leak or signs of water intrusion. Manifolds have been leaking water to the outside for a while, but we saw no obvious signs of water getting into the exhaust ports. There were no obvious leaks around the gasket, but it's difficult to tell for sure.
We noticed that the exhaust port for cylinder 6 looked different from the others. Where the visible surfaces in the others had a very flat black appearance, #6 had a shinier more crystallized appearance. The spark plug electrode also looked much cleaner than the others.
So, not sure what to make of it. Our next thought is to replace the plugs and replace manifolds and gaskets and see what that does. But want to make sure that there isn't something more serious going on before spending much on those parts.
anyone have any thoughts?
At over 2000 RPM, only under load, the engine produces a rattling/knocking sort of sound and produces less power than normal. Was working well at the end of the last season.
The sound seems to come from the right side (even numbered cylinders).
We removed the exhaust manifold on the right side to check for any exhaust leak or signs of water intrusion. Manifolds have been leaking water to the outside for a while, but we saw no obvious signs of water getting into the exhaust ports. There were no obvious leaks around the gasket, but it's difficult to tell for sure.
We noticed that the exhaust port for cylinder 6 looked different from the others. Where the visible surfaces in the others had a very flat black appearance, #6 had a shinier more crystallized appearance. The spark plug electrode also looked much cleaner than the others.
So, not sure what to make of it. Our next thought is to replace the plugs and replace manifolds and gaskets and see what that does. But want to make sure that there isn't something more serious going on before spending much on those parts.
anyone have any thoughts?
