It should work fine as-is, but if you expect to see the LED blink, you would probably
want a short pause after each logic state change.

I.E.;

Code:
RPM VAR BYTE
SYMBOL Estarter = PORTB.0
PORTB.0=0
TRISB.0=0

Main:
    for RPM = 0 TO 255
    if (RPM > 3) then
      low Estarter
      pause 100
    else
      high Estarter
      pause 100
    endif

    if (RPM <= 3) then
      high Estarter
      pause 100
      low Estarter
      pause 100
    endif
    next RPM
    goto Main
    
    END
This definitely works. LED blinks 4 times on each pass through the loop.