Sorry hans,
I am a good enough mechanic to know that i should get a better mechanic to
service my carb! I am rapidly learning more but i know my limits. One of my
big hurdles at the moment is the smog equipment in california. When i lived
in england, i did a lot of work on my old '73 landrover. The engine was an
order of magnitude simpler, seeing as it lacked all of the recirculation and
smog gubbins. I am slowly learning my way around that system... but it's
taking a while!
Like i said, i used to have very similar problems which cleared up once i
did some simple cleaning up of the external components of the auto choke.
perhaps your manual choke may be involved? I doubt it though, seeing as my
symptoms appeared to be due to the autochoke not shutting off properly once
the engine warmed up. Are the butterfly linkages related to the choke or
throttle, i don't have my manual to hand.?
cheers
Joe.
-----Original Message-----
From: Duinhoven_Hans@emc.com [mailto:Duinhoven_Hans@emc.com]
Sent: Monday, May 15, 2000 2:04 PM
To: JPGarner@UCDavis.Edu; Duinhoven_Hans@emc.com; mgs@autox.team.net
Subject: RE: Engine breathing & battery fit
Thanks Joe,
Mine is different a '71 B uses the old style dual HS4 SU carbs.
Also my carbs have fully been overhauled, so leaks are not expected.
The full engine is defederalised - ex Calif car...
The only rare thing which is left is the butterflies still are original, so
still equipped with an overrun valve.
Any clue?
Cheers,
Hans
-----Original Message-----
From: Garner, Joseph P. [mailto:JPGarner@UCDavis.Edu]
Sent: maandag 15 mei 2000 20:23
To: 'Duinhoven_Hans@emc.com'; MG list (E-mail)
Subject: RE: Engine breathing & battery fit
Hans,
>When driving with little throttle at an easy pace, the engine starts to
>backfire a bit.
I occasionally have the same problem, also like you it occasionally happens
when i accelerate. I have identified the following circumstances:
1. it only happens when i am going very slow (i.e. idling) in high gear, say
25mph in 4th.
2. it only happens when the engine is cold
I have put this down to the fact that my automatic choke is playing up. I
recently cleaned up the whole of the carb unit as best i could without
taking it off the engine (the idea of trying to tune my 79B to california
regulations without a CO2 analyser, and with bugger all idea of what i was
doing is a little bit too much to stomach). I used one of those
degreaser/dirt shifting sprays on all the linkages, plates, springs and
other moving parts on both the throttle side of the carb and the autochoke
side. if you do this, be careful not to get any on the engine. and always
wait for everything to be cold!
At the same time i added a bottle of carb cleaner to the gas tank. Although
this is no substitute for having the carb properly overhauled by someone who
knows what they are doing (my next big expense). It actually induced a major
noticeable improvement. The engine now idles at 1500 when warming up, rather
than about 2250 (that's a sticky choke). It hasn't back fired since, and the
ocassional "grabbing" sensation of the engine revs at low revs when cold
(which is classic of a dirty carb) have cleaned up too.
Nevertheless Humphrey (the car) is being booked in for a professional carb
overhaul later in the month (my girlfriend is beginning to worry about this
new competition for my meagre resources)
cheers
Joe.
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