Cobra overheating after new lower unit

[WardsDonzi]

Had to replace my lower recently on my ‘88 5.7l Cobra. I had a shop install a new unit from SEI. I also did the gimbal, bellows and impeller while it was all apart. The boat “tested” fine at the shop running on muffs, but when I launched it started to over heat. Water wasn’t getting to the block. I backwashed all the cooling lines and cleaned out the thermostat housing. Seemed ok after that. It ran well and stayed around 160-180. After a day out, it started heating back up at idle. I pulled the new impeller housing and it’s toast. Any thoughts?? Never had any issues before this, especially with the new unit, all new seals etc, I’m kinda stumped…

 

[Lou C]

Had to replace my lower recently on my ‘88 5.7l Cobra. I had a shop install a new unit from SEI. I also did the gimbal, bellows and impeller while it was all apart. The boat “tested” fine at the shop running on muffs, but when I launched it started to over heat. Water wasn’t getting to the block. I backwashed all the cooling lines and cleaned out the thermostat housing. Seemed ok after that. It ran well and stayed around 160-180. After a day out, it started heating back up at idle. I pulled the new impeller housing and it’s toast. Any thoughts?? Never had any issues before this, especially with the new unit, all new seals etc, I’m kinda stumped…

Did they replace the water tube gaskets and use the plastic guide to line up the water tube? That’s the one thing that can go wrong with putting the 2 drive units back together

 

[WardsDonzi]

I can’t speak to their process, but I’m assuming they did as they work on a lot of this stuff… the gaskets were all new with the new lower.