E250DHLAAB S/N 5364476. This past Friday I took boat off the trailer and it was running kind of rough at idle. Trolled to fishing spot then went to get up on plane and it didn’t seem like it wanted to get up on plane and when it did I hit about 4500 rpms and the water temp alarm went off. Went back to neutral and didn’t put it back on plane again. Tell tale is fine but water temps at lake were 90 and above so the water was very warm. Got home three hours later and hooked to hose with colder water and ran up to 2000 rpms and no problem. I’m a rookie at engine work so not sure what it could be. Thoughts?