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MG Midget and Sprite Technical - Help with a partially desmogged midget

My 1976 midget 1500 (stromberg Carb) has been desmoged to a point. The air pump removed along with other parts (Diverter valve, flame trap line, mechanical fuel pump( electric pump now) air temp control valave and hose, erg valve flame trapand other parts I'm not sure of). This was prior to purchase. I need help identifying what I need to keep and what can be discarded. Also what lines go where? I have several pics of the setup as it sits and I know in my heart its wrong .

In particular there is no line to the vacume advance on the distributer. I know I can remove the rails and plug the holes. What else can go?? Where does the erg valve hose go to? Car runs but is very rough and carb adjustment is almost impossible, due I feel to vacume issues, Oh my:)
If needed I have more pics of the lines etc.

Thanks for your help

Terry


TM Linden

Terry -

At a glance, things look pretty much okay. Your setup is simpler than mine, in that the earlier 1500s used only one charcoal canister. (My '78 has a second one down front, alongside the radiator.)

It's a good idea to keep the charcoal canister intact and connected, as it draws no power from the engine in operation, and captures vapors from the fuel tank and float chamber that would otherwise be vented to the atmosphere. The air pump can go, and the holes plugged, as mentioned.

As for vacuum advance to the distributor, is your dizzy fitted with a vacuum assembly? (FYI, the later Midgets used a vacuum retard, not advance.) In my case, I'm using a Mallory distributor that's totally mechanical advance, so I don't have it hosed to the carb. The distributor vacuum advance, by the way, is plumbed to the same attachment as the hose from the EGR valve. So if you've removed the EGR and have no need for distributor vacuum, you can just plug that port.

As for the rough running, the problem may be in the carburetor itself. You'll need to check the diaphragm under the upper cover, as this is the seal that ensures that manifold vacuum is properly applied to the air piston in the carb that varies the venturi and meters fuel flow. This diaphragm can deteriorate with age, and fail outright if exposed to starting fluid.

You'll also want to check the float height, the condition of the float valve, the condition of the metering needle, etc., as well as for air leaks around the throttle shaft - although the Zenith carb has a neoprene seal around the shaft that should keep air out, if it's intact.

That's all I can think of at the moment, but keep us posted with progress. More pictures will help as well.

Best of luck,

-:G:-
Gryf Ketcherside

This thread was discussed between 08/10/2011 and 12/10/2011

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