I have water coming from the centre of the small round protrusion to the left of the uppermost sparkplug on my mariner 75 (1987). Is this the thermostat housing (it looks as if the housing can be taken off with apx 8 nuts) and should water becoming out of the hole in the middle. It is filling up the calm shells, rusting my spark plugs and causing the engine to miss fire!.<br />I know I should have a repair manual but I have only just gotten into power boating and this is my first OB.<br />Thank you<br />Jon
