Defently gett it in the water as soon as its started otherwise no cooling and that can melt your exaust gasket ive seen it happen b4 not often normaly on little .15/.28 sized engines your problem just sounds lke a exaust gasket and put your exaust back on gaskets are like 40p over here so they should be as cheap if not cheaper over there
Hope this helps
John : ) : ) : ) : )