After getting back from our summer on the boat with no issues we left the boat for a week in the marina.
When we returned for a short trip it would not start. It turned over but instead of firing up after a few seconds it just kept on going. I pumped the lever on the fuel for a minute and tried again and it started after about ten seconds or so.
I had a look at the fuel filter, it was still clean, but changed it anyway. We went for a few days trip and each morning it started as normal.
Today after leaving it for a week, again it would not start. Pumping the fuel for a minute and again it started.
It has always been very reliable in the past, starting on freezing cold days after having been left for weeks, without a problem.
Any ideas would be welcome.
I will reply later if you have any questions.