timing and vac advance

[horrace]

had the engine fiddled with on a machine the other day (not by choice) , apparently it was 11 but they got it down to 6? now it back fires and feels like its dragging an anvil. ive checked the plugs and they are a good colour, so i adjusted the timing by ear and felt for a smooth running engine and its a lot lot better, just need to advance it a bit more then tweak it back....
so my question is.... why did the super dooper machine get it wrong, if it did?
and my other question is if i remove the vac advance pipe off the carb it sucks soo much it almost whistles, is this normal? and it kind of sounds better when the vac advance is removed!

[bmcecosse]

I have no idea what the 'machine' was doing ??? And what was '11' and then '6' ??? And why was your engine on it anyway?? Yes - with the vac pipe off it will suck in air - and if it's better then perhaps it's rich at idle ? Have you tested the vac advance by sucking the pipe - and watching the baseplate for movement?

[horrace]

yes base plate moves ok. tip of plug is nice brown grey colour although black round threads. garage put it on machine as a treat for me i guess? maybe it was the co2 reading?

[bmcecosse]

Well they really mucked it up - didn't they! Steer clear of them in future - they obviously have no idea....... The emissions on a Minor are just 'visual' - no need for machines.......... It's CO they measure (and HC) - but not necessary on a Minor.

[horrace]

but why is it so far wrong? the computer said it was great?!

[bmcecosse]

Garbage in = garbage out.... It was probably setting for minimum idling emissions - but useless for running........