User Manual
14
It is suggested to use as heavy and rigid as possible engine mounting for highest performance and 
safe  running.    Conventional wooden  mounting  beams should  be  of  rigid  hardwood and  of  at  least 
15mm or 5/8-in square section. Use at least 3mm steel screws, such as Allen type, with locknuts, for 
bolting the engine to the bearers..
INSTALLATION
CORRECT
Top surfaces are in the same plane.
INCORRECT
Rear view
Side view
Re-align the surfaces
as necessary
Opposite beam
Top surfaces are not in the
same plane.
Engine does not rest firmly.
Top surfaces are not 
in the same plane.
Make sure that the mounting beams are parallel and that their
top surfaces are in the same plane.
15
How to fasten the mounting screws.
Hardwood mounting beams
Radial motor mount (cast aluminum)
Tighten second nut
firmlydown onto first nut.
Tighten this nut first.
Steel washer
3.0-3.5mm steel nuts
3.0-3.5mm steel screw
Spring washer or 
lock washer
15mm min.
15mm min.
Hardwood such as 
cherry or maple.
Spring washer
3.5mm
steel Allen screw
● 
Make  sure  that  these  mounting  beams  are 
accurately aligned and firmly integrated with 
the  airframe,  reinforcing  the  adjacent 
structure to  absorb vibration. Use  4mm or 
larger steel screws, preferably Allen type 
hexagon  socket  head  cap  screws,  with 
washers and locknuts, for bolting the engine 
to the bearers.
O.S. Radial Motor Mount
A  special  O.S.  radial  motor  mount  (Code 
No.71913000)  is  available,  as  an  optional 
extra,  for  use  where  firewall  type  mounting  is 
required.










