Two more unofficial economic indicators bolstered the signlas yesterday that government statistics have been sending -- that the industrial sector is continuing to boom but the rest of the economy is beginning to slow.

In a significant report, the nation's machine-tool industry reported that new orders for its products continued to rise at a near-record pace in February, indicating industry has no plans to slow its output.

At the same time, a monthly survey by The Conference Board showed the volume of newspaper want ads across the country fell again in February for the second month in a row, pointing to a cutback in business hiring plans.

Although the two indicators are not given the weight of official government statistics, economists watch them with interest as further signs of broad economic trends that may be developing.

Official government statistics have been sending mixed signals in recent weeks, showing the industrial sector continuing to overheat while other portions of the economy, such as housing, are beginning to slow.

This apparent continuation of the industrial boom is causing a dilemma for Carter administration policymakers, who fear it is contributing to the recent speedup in inflation, but are reluctant to act quickly to slow it.

The developments came as, separately, Wharton Econometric Forecasting Associates at the University of Pennsylvania revised its 1979 econoic forecast to show a sharp slowdown in the economy between April and June and a later easing in inflation.

Wharton predicted the economy's growth rate will slow to an annual rate of less than one percent in the second and third quarters, and that inflation would ebb from a 9.2 percent rate now to a 6.5 percent pace by autumn.

The figures on machine-tool activity showed new orders for February running at $447.4 million -- 14 percent below January's boomy level, but still a full 44 percent above that of a year ago.

For the first quarter as a whole, new orders are running about 50 percent ahead of the period a year ago, and most likely will be the highest for any quarter on record.

The Conference Board's want-ad figures fell 3 points in February below January's index level of 161 -- a benchmark 7 points below December's peak. Although part of the dip stemmed from bad weather, officials said the trend was down.