Everyone
Am having continuing engine problems with the JXD Hercules in my
M8 Greyhound. This problem is a known event amongst Greyound/M20
owners and yet no-one seems to have a solution other than to bolt
on an NOS Carby. I did find that the miss could be eliminated if
the idle mixture screw was screwed down hard against its stop. So
I have assumed carby problems as per the known tendancy, but am yet
to be convinced this is so. After all the Zenith M29 Carby is about
as basic as you can get!
Here is what happened. We went on an outing and the vehicle was idling
and behaving just fine. It sat for about 5 hours (not that I think the
time factor has anything to do with it) and then we returned home. It
was upon arriving home I noticed a distinct miss at idle which
gradually becomes unnoticable the higher you lift the revs, but at
least 1200rpm of more is needed before you can no longer hear the miss,
which is probably due to too much fan noise more so than the miss going.
So far, I have pulled the head off, checked the valves and pistons.
Refitted the head after having it refaced, fitted a new head gasket
using Hylomar (Rolls Royce super dooper head gasket cement). Pulled
down and cleaned the carby (John Seidts is sending me Carby overhaul
info). Replaced the spark plugs, run substitute spark plug and coil-
to-distributor HT leads. Checked points.............All to no avail.
If anything, the miss is now worse.
So back to the carby. Having pulled down the carby, cleaned it, made
new gaskets and put it back together; I now find that the setting of
the idle mixture screw now will not eliminate the miss, so something
has worsened - perhaps by coincidence, perhaps due to something I have
fiddled with? I can only presume due to the need for the idle mixture
screw shut off in the first place that the carby is letting through
too much fuel - but how and why?
The strange part about all this is that the engine still seems to be
delivering full power and starts okay and in all other respects seems
quite sound............ Weird.
Pulling on the choke makes the eninge run rough and start to stall, when
the choke is let go a puff of black smoke is emitted from the exhaust,
which is what I would expect of any motor.
Assuming:
A) This is a carby problem, then just what the heck is it? There just
isn't that many bits in a Zenith M29 that can go wrong, it isn't as if
the main jet can wear out in 1 hours driving in one day or anything
ridiculous like that?
B)If it isn't the carby, then what is it?
The only other thing I can think of is advance/retard weights in the
distributor sticking?
-- Regards Doug++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Armoured Vehicles Collector _______ _/_(_o_)_\_ ____ _/|___|_|___|\_ /____\ / [___] [___] \ Douglas Greville _/[o]___\_ /\_ [o] [o] _/\ Broken Hill __/=_|____|_=\__ |w||___________||w| N.S.W. /__\__________/__\ |w|\u u/|w| Australia |w| \ / |w| |w| \_________/ |w| |w|$ \______/ $|w| [w] [w] [w] [w] M8 Ferret dgrev@ruralnet.net.au
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