Normal running lights for your vessel type. Your engine issue is only of concern if another vessel comes along and, for some very particular reason, is constrained from altering course, in which case explain on VHF. In all other cases vessels are required to keep clear.
I disagree. Under what circumstances would a vessel stopped be required to “manoeuvre as required by the rules”? You are stopped for whatever reason and another vessel comes along and is required to keep clear anyway. If you are stopped, you have no requirement to move to keep out of the way of another vessel.
Which rule requires that?