I'm not sure if this is the correct place to post or not, but this is my problem. I have a 1981 Sting Ray with a 140 I/O MC. When I'm goping along at crusise say around 3000 or even below I get this large fountain of water shooting up from the rear of the boat about 3 feet high, doesn't seem to matter how the plane is set. Last night I noticed while coming back home that it did not, I was traveling around 12 MPH at the time. Can anyone tell me what's causing this and is it nornal, seems like a lot of water. I do have a trolling buddy, but it's in the raised position when this occurs. Could this be from the exaust?