Word to the wise:
Treat the pull starter gently. The plastic gear is a weak link and hard to find!
Edit: Try looking inside the 'pan' the engine sets into for a data plate. IIRC that is where it is located on my '76 Chrysler 6 horse. You REALLY need to find it to be certain that the motor is a '73 or later production. Earlier models used a 10.6 Cu. In. powerhead and the recommended fuel/oil mix was 16/1. With the advent of the new 8.99 cu. in. powerhead in '73 the recommended fuel/oil mix took the quantum leap to 50 to 1. Even tho the earlier 10.6 engine had true anti-friction bearings I'm sure that the design engineers had good reason to specify 16/1 and the much thinner mix for the later engines would probably ruin it very quickly indeed!