How time flies! It is
already well over a month ago, that I decided I needed a few spacers to go
between the fuel pump and the engine block. The idea was that fitting the
spacers would reduce the throw of the fuel pumps arm. This way I hoped the fuel
pressure would be lowered enough to get the car running well enough to drive
her to friend's garage. And there I would be able to check the fuel pressure
from the fitted mechanical fuel pump. It turned out I was on the wrong track!
Fitting various spacers (ranging from 1,5 up to 6 mm) didn't change the
engine's running at all. Luckily they were not very expensive to make ...
Though a round trip
to pick up the fuel pressure gauge from a friend would have been slightly more
cost effective. Which I eventually did as I couldn't get a decent idle from the
engine. So I had to take the fuel pressure gauge to the car, just to rule things
out! With the pressure gauge plumbed into the fuel supply system I found out
that the fuel pressure was actually pretty low at just 0,07 Bar (or 1,0 psi). So
not a chance that the carburettors were over fuelling because of the fuel
pressure being too high!
I already had checked
the free movement of the floats and the proper functioning of the needle
valves. And these had turned out to be fine. As there still was some fuel
sitting around the jets, it did look like a float problem. As the carburettors
are fully rebuilt I presumed that the floats were set correctly. But I decided
it would be well worth another check. The front float turned out nicely within
the prescribed range. Though the rear one wasn't. With the float cover held
upside down, the float wasn't resting on the float needle but on the float lid
itself, though it just closed of the needle valve. But not fully
compressing the needle valve's spring! Luckily I found a thin spacer
for the needle valve seat in one of my spare carburettors. This brought the gap
between the top of the float and the lid within the prescribed range. And after
that I was able to start adjusting the idle speed. That's when I found another
small problem. The throttle lever pins to be precise:
I had placed them to
far apart on the spindle, resulting in them locking inside the throttle levers.
Again a small gain! With these two jobs completed I was able to bring down the
idle speed from 2000 rpm to under 1500 rpm, result at last! And just in case I
swapped the original carburettor needles (BDL) back to see if this would change
anything, it didn't.
With the carburettors
now performing fairly well and the car driveable, it was time to enjoy today's
fine autumn weather:
This was to blow away
any cobwebs from the engine in preparation for a visit to a friend's workshop which is planned for this
Saturday. Here I have the opportunity to use his calibrated emissions tester
for fine tuning the carburettors. And a second pair of eyes to check for
anything else I might have overlooked. Yes I still have a strong suspicion I
have overlooked something simple and obvious!
As for the car, she
behaved rather well, but doesn't pull as strongly as with the slightly richer
needles (BCE), I fitted before. So these will be swapped before Saturday! And
the idle speed remains around 1500 rpm, with a slight irregularity from time to
time. Also to be continued ...
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