Our Yanmar is no longer starting at the first ignition attempt. The problem began a few weeks ago, very intermittently, very light (it would start at the second attempt).
It now takes 3, 4, up to 10 attempts for it to start, when cold.
When the engine is warm, it has so far always started at the 1st attempt.
You can hear the starting engine do a very tiny fraction of a turn, and then stop. Voltage drops to zero on the voltage indicator at every unsuccessful start attempt.
This weekend, we installed a brand new Varta battery, as a precautionary measure (the old battery was 4.5 years old). No impact on the situation, which remains the same, or worsening.
SM2K #350 (2002)
docked at Benalmádena (between Marbella and Málaga)