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MG Midget and Sprite Technical - Ignition gremlins advice please

Hi All,

Accuspark otherwise standard ignition on standard 1500.

My car did the old going rough a bit and over running two or three times then refused to start.

Cleaned rotor and inside cap. It started but rough.

Spoke to Accuspark, all OK there.

Replaced dizzy cap, cleaned all HT input leads into cap, better for about a week. Returned from 250 mile round trip yesterday to have a slight over run on switch off.

Apart from new HT leads, is there anything else I should do? In the old days I would have checked my points as well, but Accuspark obviously working, can anyone advise anything else? Last serviced about 2500 miles ago. New plugs as well as oil and filters.

Thanks in advance, Dave
Dave Squire

Maybe pinking? Check condition of the plugs to see if you're running too lean which may be due to carb set up or an airleak.
Jeremy Tickle

Classic sign of a vacume leak / dissy timming set to advanced

Im assuming you used a timming gun to set the dissy.

My guess is vacuum leak as you have gone thur everything electrical and carb settings dont just magically fall out of spec over night...but carbs do get dirty esp inside the jet tube between the float chamber and the carb

Prop and the Blackhole Midget

Classic sign of a vacume leak / dissy timming set to advanced

Also bad / low octane fuel
Prop and the Blackhole Midget


Yes timing done with gun about 18 months ago Prop. Left alone as spot on.

Plugs OK.

However, I should do valve clearance and carb balance about now methinks so will look at vacuum advance while on and associated carb vacuum pipes.

Thanks all, back if still a problem later. Cheers, Dave

Dave Squire

While your there maybe give the intake/exhauste nuts a quick twist and the nuts that hold the carbs to the manifold... and check the black carb spacer blocks for cracks also
Prop and the Blackhole Midget

You have not mentioned fuel delivery.

If the car performed well on your 250 mile round trip. then I expect the fuel situation to be OK, but a failing pump or less than adequate flow to the carbs would cause a weak mixture, localised overheating and possible running on symptoms. Plus rough running.
JB Anderson

Well look at JB anderson go

He is kicking down doors, grabbing some jersy, and taking names with numbers

Looks like we got a new competitor to play "who can fix a broken midget"

Nice call JB

Prop and the Blackhole Midget


Checking for vacuum leaks, check the I/E manifold nuts, as well as all vacuum hoses. My 79 MGB had loose manifold nuts and carburetor nuts. Major improvement in starting and performance.

The best news, it doesn't cost anything


79 MGB
gary hansen

This thread was discussed between 17/10/2015 and 18/10/2015

MG Midget and Sprite Technical index

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