I'm getting a new Mercury 6hp in the new year. Most of my use of the boat will be when I am away for up to 2 weeks. However at the location, I do not have any access to fresh water suitable for flushing the engine, nor any container to fill and run it in.
I asked at the RNLI Station close by what advice they would give, hoping for them to say that I could use their 'car washing' hose

but was surprised when hey said that as it was a Mariner, flushing it through when I got home would suffice and if I had it annually serviced, which intend to do, just a couple of times a year would do.
Is this sound advice? I would like to think so.