[Mgs] MGB Carb Qs

[Barney Gaylord]

Air cleaners provide negligable restriction to 
air flow.  As such, there should be no difference 
with air cleaners on or off.  If installing air 
cleaners makes any difference at all, there is 
something wrong with the air cleaners.  Do not 
obstruct air flow to the vent ports on the face 
of carburetor entry ports.  Installing the paper 
gasket or the air cleaner upside down could do 
that.  Aftermarket air cleaners may or may not have the required vent holes.

Do replace any damaged parts.  Look for a needle 
type that will match your installation 
configuration.  1968 had Positive Crankcase 
Ventilation and air injection.  If these parts 
have been removed, all bets are off.  Without and 
air pump, revert to needles for the 1967 model 
year.  If the PCV valve has been removed, 
seriously conisider reinstalling it.  Otherwise 
revert to open crankcase ventilation with draft 
pipe and hose connection from valve cover to the 
air cleaner like 1962-1964 models.

The engine might start without choke in warm 
weather (but it should need choke after overnight 
rest).  If it starts easily without choke when 
cold, the carbs are adjusted too rich.

I have no advice for Weber carbs, don't recommend 
them (except maybe for racing).

Barney Gaylord
1058 MGA with an attitude
http://MGAguru.com


At 11:45 AM 12/26/2017 +0000, daybell7--- via Mgs wrote:
>I plan to replace the weber (45DCOE) with HS4s 
>on my 1968 GT.  The needles are bent and a float 
>is missing.  Is it reasonable to expect success 
>by replacing these parts (and maybe jets and 
>float valves), after a good cleaning?  What needles and jets?
>
>I have shiny carb air cleaners to use on my 1972 
>Roadster with HIFs, but when I replace the stock 
>air cleaners, the car bogs and won't accept the 
>throttle.  Should I change jets?  What jets?
>
>Should a car start without choking?  Is that a 
>indication of a rich mixture if it does?  I have 
>a car with HS6s that fouls the plugs when I 
>start it and move it in and out of the garage, 
>but don’t drive it.  The car needs choked to 
>start but once started the choke can be relieved 
>immediately.  Do I have a mixture issue?  Do I need a meter?
>
>The weber runs rich and, I suppose, can be 
>corrected changing jets.  Can anyone point me in 
>the right direction in all this?  Maybe a supplier that has explanations?
>
>Thanks,
>Steve Hughes
>Gainesville, FL