I recently purchased a 1985 Hunter 34 and the deisel would not come up to speed. It would start to smoke at 2800 rpm and then stall. I read that black smoke was caused by lack of air so I opened the engine hatch and now the engine will come up to 3200 rpm under load with a 15 x 15 prop. Is there a vent for air supply somewhere on the Hunter 34 that was subsequently closed by a former owner? Or did Hunter not provide an engine air supply on this model and design the engine to run with the hatch open? Thanks for any assistance you can give.