I can relate to this. I have a 1987 175hp 2 stroke on my Cabo 216. For many years I used to flush the motor with ear muffs with no problems. I had to replace the lower end, I did the work myself and installed a new water pump and had the same experiance as you. Since it was my first time doing this type of repair I questioned my workmanship. After removing the lower end and taking the water pump apart several times I made a set of ear muffs with a hose connection on both sides to pump more water into the intake, made no differance. I took the lower end to a boat shop and showed the tech what I was doing. He said it's all good and that the motors need more water than the muffs can provide. I have no idea why they worked for years before I replaced the lower end so I put everything back together again and took the boat to the ramp. I backed her into the water fired her up and she pumped water and peed just fine.It's been at least 6 years now Now I flush my motor in a 96 gallon trash can at home.
