powell0819
Seaman
- Joined
- May 28, 2011
- Messages
- 57
http://sphotos.xx.fbcdn.net/hphotos...00720_100000780172631_935400_1459876198_n.jpg
( ^ Photo of the problem area )
Took apart the lower unit on a 76' mercruiser so we could replace the impeller. It was pretty twisted up and the ends of the fins were falling off.. Poor thing. But directly infront of the impeller housing (which would make it the opposite side of the lower unit from the prop) there is an area that has a small shaft that is turnable but only about 1/2 a turn. I dont know what it goes too but around it there is an open area that doesnt appear to go to anything. It was filled with mud (in the picture mostly clean but you can see little bits of what we didnt get out just yet), grease, and rocks. I got all of that gunk out and rinsed it in water to make sure it wasnt chunks of metal, and it was indeed pieces of flat shale rock and a few pebbles.
Could anyone tell me what that area is and what that turnable shaft is? If I turn it the half turns I can hear a noise from down near where the prop hooks on but could not see any movement. I want to know pretty much could that gunk and rocks be a big cause of our overheating issue, or would it just be that the impeller was completely warped around with the fins falling off and cracked halfway through? It only overheated when the engine was at an idle or very slow speeds, but if we gave it more throttle it would cool it down to pretty much normal operating temp after a few moments. Snagging season is coming up so we will be needing slow operating speeds.
Any advice would be greatly appreciated. Ill be spending the next few hours getting the nasty smell of this gunk off of my hands.
( ^ Photo of the problem area )
Took apart the lower unit on a 76' mercruiser so we could replace the impeller. It was pretty twisted up and the ends of the fins were falling off.. Poor thing. But directly infront of the impeller housing (which would make it the opposite side of the lower unit from the prop) there is an area that has a small shaft that is turnable but only about 1/2 a turn. I dont know what it goes too but around it there is an open area that doesnt appear to go to anything. It was filled with mud (in the picture mostly clean but you can see little bits of what we didnt get out just yet), grease, and rocks. I got all of that gunk out and rinsed it in water to make sure it wasnt chunks of metal, and it was indeed pieces of flat shale rock and a few pebbles.
Could anyone tell me what that area is and what that turnable shaft is? If I turn it the half turns I can hear a noise from down near where the prop hooks on but could not see any movement. I want to know pretty much could that gunk and rocks be a big cause of our overheating issue, or would it just be that the impeller was completely warped around with the fins falling off and cracked halfway through? It only overheated when the engine was at an idle or very slow speeds, but if we gave it more throttle it would cool it down to pretty much normal operating temp after a few moments. Snagging season is coming up so we will be needing slow operating speeds.
Any advice would be greatly appreciated. Ill be spending the next few hours getting the nasty smell of this gunk off of my hands.
I dont think we had any pieces of the impeller that came off.. We got lucky. It appears that all the pieces that were broken were still held on by tiny fragments. I dont know when the last time the impeller was ever changed. Up until yesterday we had no idea that it was a good thing to replace it every year. We just got it last year so thankfully we learned that info quick.
