You have to be careful of what you're getting--"bunker fuel" or "heating oil fuel" etc. Usually at a marina fuel dock, you're getting treated fuel (like with Valvtek) that's generally better for your engine. We got bunker fuel once, very cheap, and the engines didn't like it and smoked and stunk. We were glad to burn it off.
Yes it is necessary to ask.
In many places in the Northeast, home heating oil and marine diesel is essentially the same...but ask.
Most marinas I have been to DO NOT have Valvetech and are getting their fuel from distributers that add red dye to home heating oil. Same truck delivers to homes, gas stations and marinas.
I seriously doubt you got "bunker fuel" from a US distributer and ran it in your recreational diesel engines. I never have heard of home heating oil, diesel fuel for boats/trucks refered to as bunker...only the latter described fuel for big commercial or military ships.
https://en.wikipedia.org/wiki/Fuel_oil
Number 2 fuel oil is a distillate home
heating oil.
[9] This fuel is sometimes known as
Bunker A. Trucks and some cars use similar
diesel fuel with a
cetane number limit describing the ignition quality of the fuel. Both are typically obtained from the light gas oil cut. Gas oil refers to the original use of this fraction in the late 19th and early 20th centuries – the gas oil cut was used as an enriching agent for
carburetted water gas manufacture.
[8
Pitch black and thick as molasses, “
bunker”
fuel is made from the dregs of the refining process. It's also loaded with sulfur — the chemical that, when burned, produces noxious gases and fine particles that can harm human health and the environment, especially along highly trafficked areas.