No Problem
Walter,Not sure exactly where you're talking about installing the inspection plate, but I have one (installed by previous owner) on the engine cover in the aft cabin under the berth cushion. It's one of those 5-6" clear plastic screw-on plates, installed over the top of the propshaft to provide access to the shaft to align the folding prop. There is no problem with heat in this installation.I'm not sure you need the plate in the first place as the engine filter is actually a secondary filter. The primary filter is a Racor unit mounted on a stringer just aft of the stern tube exit under the rear engine access cover. This filter should stop most contaminants, and in fact did clog up on me last summer to the point of stopping fuel flow. I replaced both filters, but found that the Racor was the one that was blocking flow and the Yanmar was still okay.Hope that helps!Tim