My 86 mercury 135 black max doesn't have water coming out the tell tale. I will run it with the hose, and eventually, if I rev it up, after maybe 30 seconds, water starts coming out weakly from tell tale. I replaced the impeller and the thermostats, but nothing changed. Out of curiosity, I ran it for a few minutes with no thermostats, and water was shooting out strong then. I'm not sure what I should try next. No alarm comes on from overheating, although I'm not sure if the alarm works.