Hey guys, sorry to revive an old thread, but I think I have a related topic. My non-return valve is mounted on the main filter lift-pump inlet. Is there a reason for this, or is it incorrect? By the way, my vessel is ocean going, not a canal boat, but this forum seems the best place for info on my BMC 1.5. I have a photo, but not sure how to add it here.
Edit - she ran a few months ago, but with a low pressure problem, now she won't start. The spring in non-return valve was destroyed, I replaced it, but after reading this I realise that could be my problem. However, the valve in it's current position should allow fuel to flow in correct direction, but could restrict it's flow somewhat.