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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