2005 Mercury 25hp no water from indicator hole before or after impeller replacement

[SlowSL]

Hello everyone. My father passed away a few months ago and I've taken over some of the duties over at my mom's house. I put his pontoon boat in the water and fired up the engine (2006 Mercury 25 hp 4-stroke) and noticed right away there was no water coming out of the indicator hole. It was all working fine before we put it up for the winter. I should probably preface this by saying that the only thing I've done on an outboard engine is pulling the LU and changing the water pump. I have lots of engine experience though, I'm pretty good at turning a wrench. So, I drove it over and parked it on the pier and did some research that night. Everything I've read says it's likely an impeller, so I went ahead and ordered a new kit. I pulled the LU off last night and the old impeller looked brand new. I went ahead and replaced the impeller, sleeve, gaskets and plate. Stuck it back in the water and still no water out of the indicator hole. I can feel air pumping out of the indicator hole though, and the shaft is for sure spinning, and the (not sure what it's called) shaft keyway pin is in place. I'm still going to try to blow air/water through all the passages to make sure there is not a blockage, but figured I'd post in case someone has some suggestions to save me some time and money before I remove it from the boat and haul it up to the garage. I will first pull off the lower unit and make sure the copper tube was properly inserted into the rubber grommet of the pump. I'm then going to see if there is a way to pull the little grating covers on the intakes and make sure there is not anything clogged there and make sure the passage is clear to the impeller. Then I plan to blow air/water into the copper tube and see if it's coming out of the exhaust chamber. Isn't that the only place the water goes(other than through the engine when the thermostat is open)? If it seems to be clear, what else could possibly be the problem? Thanks in advance.
-Mike

 

[itspossible]

I had the same problem with a 40 hp. I blew air into a square box that one of the water lines ran into up on the head. Something blew out of there and all was well.

 

[SlowSL]

I had the same problem with a 40 hp. I blew air into a square box that one of the water lines ran into up on the head. Something blew out of there and all was well.

Yeah, I'm hoping it's just something blocking the passage, guess I will give it a shot and see. Are there any other problems that may keep water from pumping other than a blockage or impeller? Even if a thermostat problem, water should be allowed to pass all the way through correct?

 

[Texasmark]

Where does the pee hose originate? How about a couple of good clear pictures of the pee hose where it attaches to the water source.

 

[SlowSL]

Okay, so I unhooked everything and brought the motor up to the garage. That was not a fun job. That thing weighs more than it looks. Anyway, removed the lower unit once again, made sure that the copper tube was indeed plugged into the pump housing. I removed the inlet grates and blew air into the inlet, making sure it had a clear passage through the pump. I then put the hose up to the copper inlet tube and blasted some air...... nothing. Since the tube was bevel cut, I crammed the rubber tipped air nozel in there really hard and tried again. After a few seconds of trying, water & air blasted out of the tell tale, which was cleverly pointed directly at my face. I nearly fell over backwards when it let loose. I thought the larger hole directly in the back of the motor was the tell tale, but the air/water came out from a small rubber plug on the side of the motor. So my question is, what is the larger hole in the back of the motor? It shows signs that there was once water flowing from it (stain marks).