Rotorpilot1969
Seaman Apprentice
- Joined
- Sep 8, 2012
- Messages
- 35
I have a 1999 ebb tide with merc 5.0 and alpha one gen two. I just did a complete bellows make over and replaced the drive impeller. Last year when I parked the boat it was running fine. This spring I decided to do the impeller, gimbal and ujoints because they hadn't been done that I knew of. Yesterday I hooked to the water muffs and the boat got a little hot and I shut it off thinking not enough water pressure. So today I took to the lake and left on trailer and allowed boat to come up to temp and it reminded at 150 for a long time and thinking it was fine we launched the boat and I took off across the lake on plane for several miles at 2/3 throttle. Boat shifted and ran perfectly with no unusual issue. After 3 miles I throttled down easily and came to a idle and the boat started alarming and jumped up to near 200 and I took off to cool down the engine and it then dropped down to 125 (never seen below 150 warm ) and then would rise back to 150 or so as it always ran and all was good until I throttled down again and the issue repeated itself. I removed the small left facing engine thermostat hose and started engine and it had a really good water flow. I did no other trouble shooting because it was getting dark and just loaded boat and came home. I don't think it's my thermostat because I believe it would be a opposite heating issue. Could the pickup tube in the lower unit be off set or even have a hole causing a vacuum ? Could my engine water pump be faulty? I just don't think I did anything wrong. My old impeller was in excellent condition so I don't see a obstruction in the system causing this problem. I replaced the water tube in the gimbal housing and can't see it being twisted. I just wonder if it had a blockage in it because I never looked in the tube. It was new. All help appreciated.