the reason I took the video is to show just how much force a clean exhaust system has to expel the exhaust and cooling water.
That said ... black smoke is generally badly burned diesel ... does low compression also give badly burned diesel?
another symptom we had was that black smoke also backed out the air filter as the engine died ... but you are not at engine dying stage yet? we don't use filter element in air filter ... think those filter gizmos were for operation in desert sandstorms.
