KAHULUI, Maui — Gas pumps all look pretty much the same. You can't tell by looking which ones are going to go bad.

The state Department of Agriculture is responsible for checking pumps and other commercial measuring devices but acknowledges it hasn't done so regularly on Maui since 2004, The Maui News reported. It hasn't been able to fill the full-time inspector position, which requires ability to handle algebraic equations, in Maui's tight labor market. Several candidates were examined last month but none qualified, according to Agriculture Department officials.

The Measurement Standards Branch will try again this month.

In the absence of government oversight, commercial inspection and repair companies watch over pumps. Maui Oil Co., which is both a distributor and a retailer, uses M. Nakai Repair of Honolulu to maintain its pumps and calibrate its meters. Since it both buys and sells, Maui Oil faces the possibility of being shorted if meters are out in either direction.

Out-of-kilter gas pumps are a national aggravation, with The Associated Press reporting last month on malfunctioning gas pumps causing customers to fume with the price of gasoline climbing to a national average of $3.51 a gallon.

A common defect involves a check valve that is supposed to open as soon as the meter begins running and close when the meter stops. If it fails to open when it should, the customer is charged for gas that isn't pumped; if it fails to shut properly, the customer gets gas that isn't charged on the meter.

John Guzman, the maintenance supervisor at M. Nakai Repair, says there is no simple way to do preventive maintenance on a pump meter.

"That's a very difficult question," he said in a telephone interview from Honolulu on Thursday. "It's a moving mechanism."

Although the state does not require meters to be checked annually, they must be registered annually.

Guzman says his company does not usually do regular inspections for clients. "The only time we come out to check for failure is if we receive a call."

Terry McBarnet, co-owner of Maui Oil, says his company takes a number of steps to make sure its gauges for dispensing fuel are accurate.

For the retail operation on Lana'i, it starts at the originating tanks, which are calibrated. The level in the tank has to be adjusted for the temperature, since the liquid expands as it gets warmer.

When a barge delivers petroleum to a storage tank on Lana'i, a dipstick is used "to roughly figure out" how much is there.

"On the way out of the terminal, it goes through a meter."

Maui Oil pays to have its meters calibrated once a year.

Then, the fuel is metered a third time when the customer pumps it into a car.

On Maui, Maui Oil has meters on the line at which it receives fuel from the refiners on Oahu and at the other end where it sells to retailers or direct to customers.

Nakai's inspections are "totally third party," McBarnet said.

"If (the meters) are not right, Masa (Nakai) makes 'em right."

Guzman says members of his repair staff have to be certified by the manufacturers of the meters they service. Certification can require three days to a week of training and often involves a trip to the Mainland, unless the manufacturer is willing to send a trainer to the islands.

Learning to maintain pumps "is getting more and more difficult," says Guzman, as electronics take over from mechanical parts.

State inspectors do not have to be as highly trained.

To check the accuracy of a gasoline pump, the inspector pumps what is supposed to be 5 gallons into a calibrated container. The amount must be accurate to within one cubic inch to pass.

Guzman says for larger pumps, test amounts are larger, up to 1,000 gallons.

The Measurement Standards Inspector I position being recruited for on Maui requires a year of experience and the ability to express oneself orally in a clear and direct manner; perform mathematical processes including ratios, percentages and solving equations; and prepare written reports of activities, although a high school diploma with courses in English and algebra may be equivalent.

The full-time, entry position pays $2,311 a month. Application forms may be filed at www.hawaii.gov/hrd/main/esd/ or the Department of Human Resources Development State Office, 235 S. Beretania St., 11th Floor, Honolulu 96813. The recruitment number is 207204.

For more Maui news, visit www.mauinews.com.