  We report ASCA GIS and SIS observations of the nearby (D = 11.6 Mpc), nearly
edge-on, starburst galaxy NGC 2146. These X-ray spectral data complement ROSAT
PSPC and HRI imaging discussed by Armus et al., 1995. The broad band (0.6-9
keV) X-ray spectrum of NGC 2146 is best described by a two component model: the
soft X-ray emission with a Raymond-Smith thermal plasma model having a
temperature of kT $\sim 0.8$ keV; the hard X-ray emission with a thermal plasma
model having kT $\sim 8$ keV or a power-law model having a photon index of
$\sim 1.7$. We do not find compelling evidence of substantial excess absorption
above the Galactic value. The soft (hard) thermal component provides about 30%
(70%) of the total luminosity in the 0.5 - 2.0 keV energy band, while in the
2-10 keV energy range only the hard component plays a major role. The spectral
results allow us to set tighter constraints on the starburst-driven superwind
model, which we show can satisfactorily account for the luminosity, mass, and
energy content represented by the soft X-ray spectral component. We estimate
that the mass outflow rate ($\sim$ 9 M$_{\odot}$ per year) is about an order of
magnitude greater than the predicted rate at which supernovae and stellar winds
return mass into the interstellar medium and, therefore, argue that the flow is
strongly "mass-loaded" with material in and around the starburst. The estimated
outflow velocity of the hot gas is close to the escape velocity from the
galaxy, so the fate of the gas is not clear. We suggest that the hard X-ray
spectral component is due to the combined emission of X-ray binaries and/or
young supernovae remnants associated with the starburst.
