Overheat Issue - Mercruiser 4.3/Bravo3

[FtsyMarine]

1997 Mercruiser 4.3 EFI/Bravo 3.

Port motor was not pumping water when hooked to a hose on the trailer. Chunks of old impeller were found lodged in TStat housing. After removal, water was pumping out of the drive and boat was splashed.

Boat overheated after about 10 mins of runtime after splash.

New sea water pump, water circulation pump, manifolds and risers, water tubes in drive, exhaust shutters, bellows, gimbal bearing, and thermostat just installed (less than 2 hours of runtime).

I get a strong flow of water when removing any of the 4 hoses at the TStat housing when running. TStat housing gets too hot to touch, but manifolds and risers much cooler. Hose from TStat housing to water circ pump had blackish water when drained, but seems to be clearing up a bit. I’ve confirmed that the Water intake on the drive is clear of any growth or debris and it does still appear to be pumping water out.

Boat is a 1997 Pursuit Denali 2860, and I do have a thread posted on this forum for some of the work I’ve done on that. Just looking for a bit more exposure with new thread.

Thanks in advance!

 

[merc120_81]

I had a similar issue, but didn't find any rubber in the tstat housing.. my blockage was a small piece lodged in the 90 degree elbow in the transome plate, where the rubber hose (replaced in your bellows job) attaches. mine would idle all day long, but after about 15 minutes any where above 2500 rpm, temp would climb, was just not getting enough water volume through. Others have said if you find rubber, make sure you find it all. put the puzzle pieces back together and remake the exploaded impeller if you are missing any chunks from it, keep digging. Good luck, its a pain, but you will find it.