MGB & GT Forum

My (new to me) 73 MGB with stock SU carbs has been running great, though it needed 2-3 pedal pumps to start. I just put on new air filters (stock)
and now the starting is really hard. It appears to be starving for fuel. Once running, it runs great and starts great when warm.

I searched similar topics and found that the choke is very important for starting, and checking how the piston movement affects the idle, etc...

So I went "looking" and found the choke cable to be very loose (non-functioning). After taking out most of the cable slack, the dash knob won't move.
Checking the cold start linkage shows the rear carb linkage very sticky. It appears that the rear carb scew on the cold start linkage that actuates the
throttle slightly...has been backed out.

I am thinking I should clean and dis-mantle & lube things to see if I can get the cold start linkage functioning, then address the mixture, which I believe is
lean, based on the rpm change when the pistons are tickled.

Probably a good idea to freshen the charcoal canister as well... If I go so far to pull the carbs...then I'll go looking for an exhaust leak around the manifold.

Any thoughts are appreciated.

I would rather just drive it...too much fiddling will cause it to go into repair phase prematurely (winter fix up planned).

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...not all who wander are lost...

Pushing the accelerator pedal on an SU equipped car has zero affect on starting as there is no accelerator pump. The choke which operates the cold start mechanism on HIF carbs is the only available start assist.

Getting the "choke" linkage to move freely should be possible without removing the carbs if due to an adjustment. If internal, removal will be necessary. Before doing anything further find reference material , e.g. manual, to explain the carbs and their function and adjustment .

Barry is right about the choke: fix the cable, so you can beef-up the starting process. Do that before you dismantle the whole damn fuel system !
Remove the air filters, start the engine and see if makes any difference,
Just simple stuff first.
If you need to adjust the mixture, BEFORE doing that be sure no to have any leak on the manifold gasket.

PS, in my case, I pull the choke and turn the ignition switch on; let it pump for less than a minute and then push the starter buttom (I don't have ignition key system, I got rid of that crap years ago). Once starts, I disengage the choke right away.

Thanks for the feed back. I cleaned the carbs and linkage in place, then lubed the linkage. I am able to pull the choke... just barely. The linkage is binding at the rear carb. I'm hoping some lube, and exercise will free it. I also adjusted the mixture on both carbs. It ran great on my cool off drive at dusk. We will see how the choke works tomorrow with a cold start.

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...not all who wander are lost...

Update: the choke linkage is working after cleaning & lubing. With the choke knob out, the cars starts right up!

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...not all who wander are lost...