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MG MGB Technical - Starting problem Webber to blame?

I run a 74 GT bored out to 1950cc, has a webber carb and uprated dizzy. I have run it in its current set up for the last 3 years without a problem. It has now decided it won't start. The engine turns over but won't fire. There is a spark at the plug and fuel entering the carb. New dizzy cap and rotar arm. The fuel isn't old and the car is run regulary. I called out the break down guy and he seems to think that there could be a problem with the webber as it makes a noticeable sucking sound if you press the accelerator whilst turning the engine over, (no idea if this is normal)Before I throw the towel in and have it towed to the garage does anyone have any suggestions......PS I'm not very mechanically minded so my skills are limited. Thanks
IJ Maynard

Try a can of starting fluid. If it fires but dosen't start then it is a fuel problem. If it doesn't fire then it is either compression or electrical in nature.
.

...and the type and model of Weber carb that you have is...???

In anycase; try pulling out the jets and blowing
them out with a shot of air. Blast out the
passageways with compressed carb cleaner.
Check the internal fuel screen.
Daniel Wong

Disassembling a carb might be beyond what somebody who is not very mechanically minded would wish to attempt.

First figure out where the problem is. Then either seek assistance or buy a book if you are up for it.
.

Thanks for your comments so far. The carb is a 45DOCE side draft with oselli intake and K&N filter.

Iain
IJ Maynard

Use a clip-on timing light on each plug lead to make sure they are all firing, some cap faults (new one noted) can stop one or more leads firing and that can be enough to stop it starting. While you are at it and on No.1 lead check that the timing is about right i.e. a few degrees before TDC.

After cranking for a bit take out the plugs and check them. Soaking wet means flooded, but you can usually smell that anyway. The cure is easy with SUs - crank with full throttle and no choke until it fires, don't know about Weber as those chuck another bucket full of fuel into the intake each time you prod the throttle. Bone dry and no fuel smell means no fuel is getting through, check the fuel supply and float chamber valve. Normally there should be a strong fuel smell but not wet with it.

I would have said it was normal for the engine to noticeably suck air (and fuel) when the throttle is opened, that is what makes it go faster after all.
Paul Hunt 2

This thread was discussed between 14/01/2007 and 16/01/2007

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