Adrian,
Sounds like you're running rich. This basically means you're getting too
much fuel, or too little air. Knocking that hose off opened up another
air path to the carb, leaning out your mixture and making the car run
better.
Given you have a '75, you probably don't have the water choke, unless
you have a California car. But if you do, the choke is a big suspect in
running rich. Here's a step-by-step processs to rebuild it.:
http://www.paulbunyan.net/~jasko/choke/
I'd also give the emissions hoses and canisters a good looking over.
There are restrictors in the hoses at the connections with the charcoal
canister. Some are as small as 1/32", and may have clogged. Check also
to make sure the carbon itself is OK. The bottom of the canister will
unscrew. Sometimes the internals of the canister will deteriorate and
the carbon will plug the lines.
Ypu may also have sludge buildup in the valve cover under the vent.
You'll need to take the cover off for this, but you should be able to
use spray carb cleaner or a similar solvent to clean it out.
If all this checks out, then you can adjust the mixture in the carb.
You'll need the specail ZS allen wrench tool, which keeps the piston
from moving relative to the needle adjustment.
Others will have other things to check that I missed. Good luck!
-=Chris
<-----Original Message----->
From: Adrian Jones
Sent: 6/24/2006 4:12:23 PM
To: spridgets@autox.team.net
Subject: Tuning a 1500 Midget (1975 with 150 ZS CD carb)
Hi again,
Lacking a CO analyzer, I've been going by the color of the spark plugs.
Black sooty plugs and only getting 22 mpg (US gallon).
Then I accidentally disconnected the hose from the carb that T-bones the
hose from the charcoal canister to the valve cover. The car ran
noticeably better (felt like it revved more freely) and the plugs went
to a nice light brown color.
Obviously, I canbt leave it like that b grit getting into the carb and
valve cover.
Any thoughts?
Regards, Adrian
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