Having issues with Lehman SP 135
Good afternoon all, My 1990 Lehman SP135 engine has developed a noise while running that sounds like an exhaust leak coming back through my air intake manifold. I noticed this once recently right after start up a month or so ago but it went away within a few minutes and didn't occur again until we were following the Anguilla Championship sailing boats Sunday afternoon while coming back. This time the noise was accompanied by what sounded like tappet noise as well.
My first thought was that I had a valve sticking, or not closing properly, so I followed forklift's valve adjustment guide to a tee actually going through the process twice just to make sure I got everything correct but unfortunately, After valve adjustment, the tappet noise went away, but I still have the issue of what sounds like exhaust noise (popping noise)coming out of the air intake manifold. Does anyone have an idea of what is causing this?