I have a 71 25 hp Evinrude and the pee stream is weak. Water pump and thermostat was changed about two years ago or less. I read on here not long ago about what you use as an acid or mix a concoction to rid the lime buildup in the water galley. Can anyone help me out or suggestions?

It is best to do the descaling with the lower off so you can cap off water tube. Plug it and the pee hole then pour full of Limeaway at the thermostate and let set for 2 hours. Go ahead and replace the impeller.

Thanks Gary. Is this a common?

Not on your motor. Mostly on the late model Yamahas.

ok, thanks!

Found the culprit. Removed the stat and bought a new one. Dropped both of them in hot water and the new one opened up quicker than the old one. Go figure. The old one was less than two years old..........Going to replace impeller while I'm doing maintenance.........

WARNING!, went ahead and changed the water pump while I was doing maintenance. Removed the impeller housing and had the end of a vane fall on the ground. The housing on the inside was gaulded and the wear plate worn. This is the result of starting a motor for a brief time out of the water. At the most of any time, less than 2-3 seconds. This pump was replaced less than two years ago.

mercury says every year. i would use that rule on everything.dont want it to poot out in the middle of the lake

Made a believer out of me!

Mercury impellers, IMO, are the weakest between Merc and John/Rude. Never had a Merc last more than 18 months. Johnson and Evinrudes lasted me several years. Only changed them cause I was scared. My Mercs would peter out and trigger alarms. Just my experience. I love both brands but have owned way more Johnsons.