This leads on to the problem I have been having with my Poulan. Seems a number of manufacturers use the pressurisation of the bar oil tank from the crankcase pressure. When I bought my saw brand new, the vendor said "When you turn it off, crack the oil filler cap to release the pressure otherwise all the bar oil will be pushed out" - or words to that effect.
Decided to have another look at the Poulan this afternoon and discovered a plug under the clutch which, when I removed it, is obviously the pressure transfer arrangement between the crankcase and oil tank.
Blew it all out with HP air and by mouth determined that it was clear. Reinstalled and started her up but still no oil to the bar and no "PSSSST" when I crack the oil tank filler.
Still thinking about it. Can only be something simple. Determined to succeed as I cannot afford a new (even secondhand) saw.
Will report back.
Jim