BLUE RIVER, Wis., Aug. 24— Alvin Straight, who is 73 and too blind to get a driver's license, recently drove 240 miles on his lawn mower from northwestern Iowa to southwestern Wisconsin to visit his ailing 80-year-old brother, Henry.

When Alvin Straight learned that his brother had suffered a stroke, he bought a 1966 John Deere lawn mower, got a 10-foot trailer to haul gasoline, clothes, food and camping equipment, and started driving on July 5.

On good days he averaged about five miles an hour along U.S. 18. But about four days into the trip, the engine failed on his mower in West Bend, 21 miles from where he had started in Laurens, Iowa.

Mr. Straight spent $250 replacing points, the condenser, plugs, the generator and the starter.

He made it to Charles City, 90 miles from West Bend, when he ran out of money in mid-July, and had to camp out until his next Social Security check arrived.

By Aug. 15, he had made it to within two miles of his brother's house near Blue River, but then his mower broke down again. A farmer helped him push it the rest of the way.

Henry Straight, who did not know his brother was coming, said on Tuesday: "All I could do was unhitch his mower. It ain't hard to unhitch."

Alvin Straight said he might head home in about a month. Despite offers of help, he said he planned to make the return trip on his mower.

Henry F Straight