http://www.youtube.com/watch?v=v5vZAKuo7ug
This is a video of my 15 hp Evinrude. I have been having this problem for the past several months. At first it was diagnosed as a spun prop. Well well it isn't the prop (I think). The prop in the video maybe has 10 hours on it. The basic problem is at WOT it will rev very high, but looses all power. You will here the over rev at about 18 seconds. I immediately throttle down because it sounds like the engine will explode if you hold it there. When throttling down it seems like it will kick back into gear, or catch. It seems like different trims make it worse, and the cavitation plate still seems too low, but if I raise it up the over revving becomes worse. Gas tank is in the front. Battery is in the back. It doesn't do it as often or if at all with one man. 13 foot boat, 2 men to 320lbs, gas, battery, and fishing gear.
An interesting side note is this boat came with a 12 hp Sears motor and it made a similar noise when turning hard one way or the other. My buddy and I discussed why with all the outboards we have used all the motors make this noise on this boat. We did recently replace the transom which originally had a hook on it (The angle of the transom left a portion of it hanging below the hull). This seemed to be taking away power and sucked dragging around for ducks. So we replaced the transom and now its parallel with the hull and a little above it. Just trying to give as much info as possible as I'd like to fix the problem. thanks for the help.
This is a video of my 15 hp Evinrude. I have been having this problem for the past several months. At first it was diagnosed as a spun prop. Well well it isn't the prop (I think). The prop in the video maybe has 10 hours on it. The basic problem is at WOT it will rev very high, but looses all power. You will here the over rev at about 18 seconds. I immediately throttle down because it sounds like the engine will explode if you hold it there. When throttling down it seems like it will kick back into gear, or catch. It seems like different trims make it worse, and the cavitation plate still seems too low, but if I raise it up the over revving becomes worse. Gas tank is in the front. Battery is in the back. It doesn't do it as often or if at all with one man. 13 foot boat, 2 men to 320lbs, gas, battery, and fishing gear.
An interesting side note is this boat came with a 12 hp Sears motor and it made a similar noise when turning hard one way or the other. My buddy and I discussed why with all the outboards we have used all the motors make this noise on this boat. We did recently replace the transom which originally had a hook on it (The angle of the transom left a portion of it hanging below the hull). This seemed to be taking away power and sucked dragging around for ducks. So we replaced the transom and now its parallel with the hull and a little above it. Just trying to give as much info as possible as I'd like to fix the problem. thanks for the help.
