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Re: MG will not rev - HELP !!

To: econ.tech.dti@gtnet.gov.uk
Subject: Re: MG will not rev - HELP !!
From: mgbob@juno.com (ROBERT G. HOWARD)
Date: Wed, 25 Jun 1997 17:50:01 EDT
On Mon, 23 Jun 1997 15:36:28 +0100 "TS Internet Machine"
<econ.tech.dti@gtnet.gov.uk> writes:
>Dear All,
>
>This is a follow up to the "Very hot coil - poor running - please 
>help"
>request from June 4th..  Many thanks to all those on the list who
>responded...
>
>I have been helping my friend with his B but we are not getting very 
>far.
>
>The car is now running (but badly - see later) after replacement of 
>most of
>the electrical lucas type bits under the bonnet and much shouting and
>swearing from all concerned... When the weather is lovely outside and 
>the
>topless MG is not working very well, the last thing you want to be 
>doing
>when it's a fantastic summers day is farting around under the bonnet 
>!!
>
>Current Situation...  MGB '74 Chrome Bumper.  Electical bits all 
>replaced,
>Points, condensor, LT lead, Dist Cap, HT Leads, Spark plugs, Coil + 
>coil
>wiring.
>
>The engine now runs but will not rev !
>
>It will tickover at 800 rpm quite happily but the instant you hit the 
>gas
>pedal the car starts to cough and splutter, backfires in the carbs and
>spurts black smoke out of the back....  It will not rev over 2,500 rpm 
>and
>runs really really rough if you try and take it over its tickover. 
>
>We've changed the fuel filter, checked the fuel delivery (sort of 
>sloshes
>out at a leisurly pace at the carbs) and even tried running the car 
>without
>a filter but no change to the situation.  One point of note is that 
>the
>plugs are really black when it's been running for a while.
>
>Can you offer any pointers for what to try or check next....
>
>The car has now been off the road for 5 weeks and his wife is getting 
>ideas
>about getting rid of the MG - too sad to contemplate losing another 
>MGer.
>
>It would be appreciated if you copied your responses to 
> 
>       Kevin.Phillips@tidv.dti.gov.uk
>
>As he is not on this list.
>
>Please Help.     
>
>Many thanks in advance.  Andy.
>
>
>
>
>
>
>However, 
>
>
Andy, 
  Five weeks with the MGB in the garage in the summer. That's cruel and
unusual punishment. That's unconstitutional. We've got to get this car
running, TONIGHT!
  What was it doing/how was it running before the work on the ignition
system? (I missed the first chapters of this tale) If you still have the
first chapters, you might post them again.
   Have you checked the PCV valve? All the little emission hoses and
their connections. Any visible cracks in anything? Any sounds of leakage
in the hoses?
  How about compression? Burned valve? Mechanical woes?
  Fuel pump should deliver about 4 psi at the carburetors with the line
disconnected.. That's a pretty healthy, pulsing flow at the end of the
hose. 
  Have you checked the level of the oil in the carburetor dashpots?
Filled it to the ring visible inside with whatever motor oil you're
using.
  Are you certain that the HT wires are really going to the right
sparkplug? 1 3 4 2 . The distributor turns opposite to what one would at
first think. Dwell angle correct? I don't have the setting for the '74,
but I sure can't set it with feeler gauges on my '72.  How about the
timing?  Book says whatever it says, but most people find that 10 degrees
or so of additional advance helps. You can set it so the engine idles
fastest if you lack a timing light, and that's good enough to get you
going well. 
  Carburetors drawing evenly? Do they make the same giant sucking sound
when you listen through a hose, or measure even with a uni-syn?  
  Maddening. Let me know.
MGBob @ juno.com
  

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