I used to have problems starting it for two decades. YOu wrote the battery is full.
I found out that even a full battery might have issues starting this engine. Have you ever compared the performance of your battery and the size of the engine versus what is in your car ?
To cut it short, since I have a Hawker battery the old girl behaves quite different and even if she is a bit uinwilling to start I have the power in the Hawker to convince her a seceond and even third or fourth time.
Ok, sounds like an advertisement for Hawker, however after 20 years of trouble I am glad that at least on that side I am covered.
regards,
Holger