While my yacht is on the hardstand I run the engine every couple of months for about 20 minutes. Since it is raw water cooled I use a fresh water hose to feed the raw water filter which in turn supplies the engine. The water flowing through the anti syphon system is still a good flow.
Usually I notice the wet exhaust spitting out water from time to time but the last two times there has been only one or two "spits" of water from the wet exhaust during the 20 minute run. Today I also noticed I could only place my hand on the rubber exhaust pipe that is attached to the mixing elbow for 5 seconds before it was too hot for me. I don't recall the rubber exhaust ever getting so hot but I could be wrong.
I suspect a problem so my questions are:
(1) Should the rubber exhaust hose downline from the mixing elbow only ever be warm to the touch?
(2) any suggestions as to where I can find online a diagram of the internal construction of the exhaust manifold and mixing elbow?