O.S. Engine 91HZ  [OSMG1975]

With back-to-back FAI world championships in 2005 and 2007, the 91SZ-H was a winner by anyone's standards. Now there's the 91HZ ?V a 91SZ-H redesigned with the help and advice of the world's top pilots. It offers the tuning ease and performance consistency of the multi-time world champion and design innovations that promote improved cooling, a tighter compression seal ?V and tuning ease!

The narrow profile of the heat sink head helps the 91HZ fit completely inside cooling shrouds without cutting or losing cooling power!
Two heat sinks ?V one on the head, another on the crankcase ?V allow airflow to carry away heat and maintain performance.
Better overall balance reduces engine noise and promotes smoother, stronger performance.
The new 61B carb takes consistency to the next level. Dependability features start with an insulating ring which prevents crankcase heat from affecting carb settings. A generous use of O-ring seals ?V two on the main needle, one on the rotor ?V prevents air leaks and power fluctuations.
In-flight control of the needle valve ensures smooth, consistent runs.

Specifications:

• Stock Number: OSMG1975
• Displacement: 0.912 cu in (14.95 cc)
• Bore: 1.091 in (27.7 mm)
• Stroke: 0.976 in (24.8 mm)
• Weight: 21.8 oz (618 g)
• Practical RPM Range: 2,000-16,000
• Output: 3.4 hp @ 15,000 rpm
• Includes: 61B carburetor, muffler, in-flight needle valve adjustment arm & #8 glow plug