MTD AC3 - Manual (Page 6)

AC3 Series of engines
2
Assembly
Torque specifications may be noted in the text that covers assembly, they may also be summarized in tables
along with special instructions regarding locking or lubrication. Whichever method is more appropriate will be used.
In many cases, both will be used so that the manual is handy as a quick-reference guide as well as a step-by-step
procedure guide that does not require the user to hunt for information.
The level of assembly instructions provided will be determined by the complexity and of reassembly, and by the
potential for unsafe conditions to arise from mistakes made in assembly.
Some instructions may refer to other parts of the manual for subsidiary procedures. This avoids repeating the same
procedure two or three times in the manual.
Description
The AC3 engine is used on a variety of handheld equip-
ment. This engine has:
• 29cc’s of displacement.
• A cantilever crank design.
• Pushrod activated OHV.
• Genuine 4-cycle design, not a hybrid 2-cycle/4-
cycle like Stihl and Shindaiwa.
• Engine covers split front and back.
Currently there are engine models in this series of
engine:
• AC3
• AC3.1
• AC3.2
The AC3 version has an 8 to 1 compression ratio. The AC3.1 and the AC3.2 have a 9 to 1 compression ratio
which increased power approximately 20%. The AC3.1 and 3.2 engines are also available with electric start versions.
Identifying engines
AC2
• 26 cc’s of displacement.
• Engine cover surrounds the cylinder head and
muffler.
Visible from the rear:
• A plastic, diagonal split crankcase sump.
• A dip stick that threads into the sump.
Figure 1.1
AC3 engine
Figure 1.2
Plastic sump
Full engine cover