Thanks GC, problems are:
Ski runs fine at speed. Good jet out of telltale vent on left side.
When running at slow speed ( 3 mph) ski will overheat after 10 -15 mins. Temp alarm + steam out of telltale.
Running at slow speed and when flushing on trailer, only occasional spurt of water from telltale.
Ski has been to dealer and cleaned/flushed....nothing found and is no better.
Any ideas ?
Was going with the blurb from Yamaha brochure that says:
Thermostatic and Pressure Controlled Cooling System: Water flow through the engine is controlled by a thermostat and pressure system and is maintained by a pressure control valve