5 replies to this topic

[Mattch]

Hello,
We took the mini for its first MOT today and it went great until it got to the emissions! It's supposed to be 4.500 CO2 I think and ours was reading 11.700! The carb was running a bit lean and the MOT man recommended a carb rebuild, Is this enough? (Our carb is a HS4 waxstat type).
Thanks matt

[KernowCooper]

With those readings its not runnning lean the upper limit on that group car is 4.5% CO and 1200ppm HC. what was yours running at on the HC.?

 

Did the MOT man not try a quick adjustment and then take a reading again? if it fails the idle limit the test allows for a reading to be taken at 2000rpm

sound like the MOT  Tester is not used to testing older cars?Have you had the plugs out they should be black at that CO reading and the MPG must be dire?

Edited by KernowCooper, 08 June 2013 - 10:24 PM.

[Mattch]

Yes the plugs are black but the car felt like it was running lean as we drove it their, and we do not know the HC. Do you think this is a problem with the carb or something more seriouse like the engine?

Edited by Mattch, 08 June 2013 - 10:32 PM.

[KernowCooper]

Has it been serviced ? plugs points condenser, timing tappets and air filter, then set the CO at 2.5-3% and go from there and ask the garage just to test the readings

[Mattch]

Yes the it's been serviced except timing hasnt been looked at. What do you mean by set the CO?

[KernowCooper]

Its the reading the MOT man is checking the CO reading on my 1980 Mini is a maximum of 4.5 % CO (carbon monoxide)   and 1200ppm HC (hydrocarbons) thats a reading of air fuel ratio and unburnt fuel. Incorrect timing could cause a incorrect reading and needs to be done before any tuning of the carb you do. You can adjust the CO manually but have no adjustment on the HC thats all down to setup of the engine and condition of the engine. Also check adjust the valve clearances.

Edited by KernowCooper, 10 June 2013 - 08:21 PM.