G'day folks!!
I am in panicsville.
I just rebuilt the ZS carb on my 1980 MGB LE. I replaced all of the
required gaskets, the diaphram and the needle valve (with a fibre washer).
I could not find any of the o-rings in the kit which seemed to fit the
obvious o-rings in the carb so they were left as is.
I also replaced the fuel pump. It was running continuously so i
disconnected the fuel line at the carb and ran the pump. Saw the air
bubbles in the catch container and decided to first make sure the banjo
bolts were tight. In the process I must have torqued too hard because i
split the plastic casing. So i had to get a new aftermarket pump from our
local LBC guru. At the same time I replaced the rubber fuel lines at the
pump. I still am getting a small amount of fuel pump running when the
ignition is on and the engine is off. Is this normal? (before answering
see below)
When i rebuilt the carb, I set the choke/throttle lever gap to 3/32" by
adjusting the idle speed screw, adjusted the throttle stop screw (and
tightened the lock nut) to set the space between the fast idle pin and the
cam to .025 ", prepositioned the course idle nut at two full turns from
full insertion, prepositioned the fine idle screw at 2.5 turns from the
full insertion position, and adjusted the metering needle (did not replace
this) so that its shoulder was even with the bottom of the air valve
piston (but I do not recall making sure that the flat side of the needle
bushing was facing grub screw). i also shook the float and heard nothing
so i assumed it was not leaking - I set its height at .625" above float
chamber face by bending tab.
Kicked down acellerator, pulled after market manual choke and engine
started immediately then red-lined. Shut dawn ASAP. Did same thing and
got another red-line. Looks like I had over tightened nut holding
throttle quadrant to throttle shaft.
Loosened nut and got it started it again and took it for a 15 min drive to
heat it up. It died a few times during this initial run but restarted
immediately.
Back to the shop. Removed air manifold-to-air hose at air pump and
plugged it with a magic marker. Pulled off float chamber vent pipe from
carb and scared the hell out of myself - fuel was pouring out of the carb
outlet onto the hot exhaust pipe. Quickly reconnected and found a long
piece of hose to exhaust fuel from carb to container on ground (I assume
this fuel flow is not how it should be).
Started engine and tried to set idll speed to 850 - no go. After the idle
speed screw adjustement failed (i could get the speed up but not down to
850) I tweaked othe screws and nothing seemed to work. Engine stalled.
I forgot to turn off key and a few minutes later i heard the pump clicking
and gurgling in the engine compartment. I saw the fuel moving in the
transparent fuel filter and tracked the loudest gurgling to the area of
the absorption cannister. On a hunch i removed the hose between the
cannister and the valve cover and fuel was pouring out of it - i quickly
stuck the hose into a bottle and then realized that the key was not off.
Turned off the key and said - "where do i go from here?" - hence this
message. I do not recall these gurgling noise before but it may have been
one of causes for the old pump running on with engine shut down and
ignition on
I am sure that the flow of fuel from the float chamber through the outlet
pipe to the cannister into the valve cover is wrong and that i have to
resolve this before i go any further.
I also have to reset the choke/throttle lever gap to 3/32" and the gap
between the idle pin and the cam to .025". Most importantly i must change
the oil ASAP to remove the gasoline contamination. But I should not do
that before I find the reason for the fuel flow.
Anyway - i am a state of panic. Can any one tell me how to diagnose the
fuel flow through the cannister? Then where do i go from there?
Thanks all - what a bummer way to end BCW.
Preston
|-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-==-=--
| It is now MGB top down time.
| Betti Ann and Preston Smith in the Head of St Margaret's Bay, Nova Scotia,
|Canada.
| email: prsmith@navnet.net
|