New member here! I have a 1986 9.9SJ with a very similar problem...no pee stream. I checked the impeller; it looked fine, but I replaced it anyway. Still no stream. Then checked the tstat; it came out in pieces. It seemed like a no-brainer at that point. Replaced the tstat...still no stream. Then replaced the drive shaft to impeller key, to be sure the impeller wasn't slipping on the shaft. Still no stream. Tried running it with the tstat removed. Still no stream. I can blow air through the entire cooling system (intake to outlet) no problem, so it seems there is no clog. After running it and looking in the tstat housing, it is completely dry, so it seems water is not making it up there. I've let it run a few minutes like this. It gets hot, but not overly so. Is it possible the cooling water lines didn't align properly when I reinstalled the lower unit. Does it take longer than a few minutes to prime the cooling system and see water flow? Could there be a leak around the pump housing causing water to just flow into the lower unit instead of through the cooling system? Any other ideas? Thigs to check? Thanks in advance!