Instead of using the $55 Heater Craft Wye, I've used a Mercruiser fitting as mentioned by baitkiller on this board (part 22-862993 WATER FITTING).
After installing this, the engine does not warm up past 120*. To test if installing the wye was casuing the engine to not warm up, I removed the wye and it now warms up to 160*.
Has anyone experienced this and have any suggestions for me?
2013 Supreme V208
Heater Craft 3 vent heater installed from the factory