Can anyone offer any advice,i have a V4 85hp that overheated,but did not do any major damage.I have changed the impeller but it still won't pump water.
Why do you say it hasn't been damaged? Just how hot did it get? It is very difficult to seriously overheat one and not do some damage. Gaskets will burn and leak. Pistons and cylinders will score. Wires will melt. It may start and run, but the damage is still lurking, ready to get worse as you use it. In fact, burnt gaskets and other parts may be part of your no-pumping now.
It depends on what year your engine is. Regarding the crossflow family: The telltale first came out on the 1978 models. An engine with a functioning water pump can still overheat at idle if the thermostat(s) are stuck shut. On the 77/older units, a water mist will come out of the two exhaust relief ports at the top of the midsection when the single vernatherm (thermostat) opens. On the 78/later units, the telltale should always function, even if the thermostats are stuck shut.
