Question

when performing vacuum testing using a vacuum gauge, a steady reading of 17\ to 21\ of vacuum indicates:
select one:
a. a burned valve.
b. possible worn rings.
c. possible late valve timing.
d. a good reading.

Explanation:

A steady vacuum reading of \(17''\) to \(21''\) is within the normal range for many engines. A burned valve would cause a lower and unsteady vacuum (due to leakage). Worn rings would lead to lower vacuum (as compression is affected). Late valve timing also disrupts the normal vacuum pattern. But a steady \(17'' - 21''\) is a good, normal reading.

Answer:

d. a good reading.