WINDSOR, N.D. (AP) — Fuel costs greater than $4 a gallon aren’t just expensive for motorists. They’re causing headaches for thousands of rural fuel dealers whose pumps can’t count that high.

Equipment suppliers are reporting a surge in demand for gear that will allow older fuel pumps, which use mechanical reels instead of digital readouts, to display prices up to $9.99 a gallon. The result is a waiting list that can last two months or more, industry officials say.

In some states, regulators are attempting to work around rules that require service station and convenience store fuel pumps to display per-gallon prices. Older, unmodified fuel pumps often cannot show prices higher than $4 a gallon.

‘‘It’s a significant problem,’’ said Mike Rud, director of the North Dakota Petroleum Marketers Association. ‘‘In some of the outlying rural areas, this might be the only pump in town that people can access.