Hi again,
I have just finished speaking to the guy at the service centre and his opinion is that I should put a new motor on it as well as a new cutter clutch. It seems that the mower has been used in it's current state and as such, damage has been caused to the clutch and drive shaft. The clutch and shaft can can be turned by hand about 20-30mm without the engine turning and apparently it shouldn't be like this. He says the key on the shaft is damage and that is why it can turn.
So, assuming that I would like to keep this motor, how hard is it to replace the clutch and drive shaft myself?
Also, worth noting is the fact that the service guy believes that the motor is not a 3HP built in 1981 but is actually an older 2.5HP motor. He thinks that at some point the crank case cover has been replaced with a newer unit hence the 3HP badging and model codes. The reason he believes this is that it looks like the engine has been painted black at some point as you can see the old orange colour in places where the black has scratched off. Is this likely to be the case? Is there any way to tell for sure? If it is a 2.5HP is it worth keeping or would it be better to replace with a more powerful unit?
Please let me know if you need photos to determine the state of the clutch or the real identity of the mower.
Steve