Tried the old trick of water decarbonisation last Sunday on my '75 Capri.
Came back from a long drive, whipped off the air filter box and sprayed distilled water right down the carb using a spray bottle, i used a little over half a liter while holding the engine at 2000-3000rpm.
It wasn't immediately noticeable but i really began noticing it yesterday :
- Idle is smoother
- Acceleration seems more linear and engine seems to rev more freely.
Until August 2016 when i changed the valve stem seals, the engine used a lot of oil, i estimated about a quart / liter every 600 miles, after changing them the oil consumption completely stopped, so i assume the inlet valves are probably very cruddy.
These are ofcourse not scientifically demonstrable, but the butt dyno says it runs better!
Bonus revving video after doing it : https://www.youtube.com/watch?v=dilsdyH5d1Y