Group: We have just finished a major rebuild of 415-CD #4787, N94676 airframe.
Restoration work was accomplished by a highly experienced team composed of an
AP and an AP/IA. The C-85-F engine was majored just prior to my purchase and
fitted with the 0-200 modification. Currently, TTSM is 28.6 hrs. As part of
the rebuild, the fuel plumbing system was replaced due to use of unauthorized
components an unworkable plumbing configuration. The new system follows the
configuration shown in Figure 34 of the Ercoupe Service Manual. All tanks are
vented with serviceable gaskets. The orifice input fitting at the fuel pump
was measured at .062". During post rebuild flight tests, it was discovered
that, although fuel was being pumped from both wing tanks, the flow rate was
insufficient to fully replenish the fuel drawn from the header tank. This was
particularly true with the fuel burn rate experienced during touch and go
landings.
We did not receive any engine performance data on the C-85-0200 engine with the
airplane. Fuel consumption data for the C-90 is appreciably higher than for
the C-85. Assuming the C-85-0200 is reasonably approximated by the C-90 fuel
consumption at various power levels, it occurred that the header tank fuel
replenishment rate for the C-85-0200 may be higher than that allowed by the
current orifice in the fuel pump of .062". So far, we haven't been able to
find data on the required orifice for the C-90 or 0200 Continental engines.
First, can anyone provide fuel consumption data for the C-85-0200 engine? Is
the C-90 a reasonable approximation? Is the restriction orifice of .062"
adequate for this engine modification, or should it be relieved? If so, by how
much? The fuel system IS transferring fuel from the wing tanks to the
header tank, but the fuel transfer rate seems to be insufficient. I am
concerned that a fuel burn rate resulting from a long climb at full power would
deplete the fuel from the header tank to an extent it would take an
inordinately long time at cruise to replenish. We would greatly appreciate any
insights, experiences, or recommendations that might be offered.
Thanks to all.
Bob Blanchard, Owner/Pilot
N94676
