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June 19, 2003
Hi, Don May...
1. The missing hose from the carb. to
the charcoal cannister MAY be for
the fuel bowls with respect to an "anti-
runon" valve feature.
This is a guess on my part. What this did
was create a vacuum at the fuel bowls
when oil pressure fell to zero through
a solenoid switch when the ignition was
switched off. The fuel bowls were vented
to the charcoal cannister as part of the closed loop fuel system. The
solenoid switch was wired "hot" which is why the
PO MAY have disconnected this.
2. The line off your timing cover to the
"Y" fitting, then on to the carbs. is your
PCV system. The fittings within the carbs.
are in themselves "graduated orifices" with respect to allowing a
predetermined
flow based on intake manifold vacuum or
whatever. The PO may have decided to
add a restrictor of his own. Whatever, it's
working correctly I guess, in terms of
"evacuating" the crankcase of vapors and
also pressure or you'd have oil leaking
or being forced out of the crankcase seals, especially at the rear of
the engine.
With respect to flat spots at mid-range.
These engines were calibrated to run
lean under cruise conditions. These flat
spots MAY be the result of this....it's
called "lean surge". You can sometimes
"feel" this (spine...or "seat of the pants")
in some modern emission equipped motor vehicles, as well.
Are the carburetters equipped with
jet adjustment nut "restrictors"...little
metal tabs that limit the travel of the
jet adjustment nuts in terms of their
"down" (richer) adjustment?
Cap'n. Bob
'60 :{)
PilotRob@... 22778
Posted on June 19, 2003 03:03 AM
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