Quick question. Ran the boat on the muffs last night for about 15 mins. for the first time this year. I did run it above idle, but below 1k RPM's for a couple mins. before shutting down. First time I ever noticed this, but after shutting the engine down I was checking around the engine compartment for leaks, etc. I noticed that the starboard riser was pretty hot to the touch, couldn't touch for more than a second. I wouldn't have thought much about it, but the port riser was pretty cool to the touch. Is this because the thermostat never really gets hot enough to open while running on muffs to circulate the water all the way through? Temp gauge looked fine. It's a Mercruiser 5.7L EFI. TIA.
