Listers,
Like I hope most of you out there, I just love the way my little 289 purrs
and I'm very attuned to anything being even the slightest bit irregular.
But I have come to take this pretty much for granted of late and in the
meantime have transferred a lot of my obsessiveness to the maintenance of
my computer. But, recently I did do some work on my Accel distributor that
included redoing the advance curve slightly, plus a few related maintenance
chores. And everything seemed great, except at real slow idle, maybe a bit
rougher than normal, but nothing too alarming. I'm driving Mr. Green quite
a bit this week, being British Car Week and all, and a couple of days ago I
opened it up for a ways. Oh boy this is great, but then it started losing
some power; not completely, but very noticeable. I backed off momentarily,
then stabbed it again and it stumbled, then kicked in again. Uh oh, what's
the problem here! From the way it felt, I'm pretty sure it's fuel delivery
not ignition, and the way it stumbled and then lit off again, I'd say the
problem is with the front two barrels, but just guessing. So, first thing I
check when I get back home are the bronze filters that are in the center
pivot float bowls and also the float levels. Nothing seems amiss, but clean
the filters and slightly readjust the float levels, meanwhile thinking
about fuel pump pressure, main filter, etc. as the possible problem. Also,
worrying a little about running flat out with too little fuel and the
inadvisability of that, the importance of a fuel pressure gauge, etc., etc.
But yesterday was a great day for Tigering and it's still BCW, so I drive
Mr. Green to UCSD and back. And each time I'm pulling away from a stop I
begin to notice some missing until it gets to maybe 1000 rpm or so, then
OK. Or is it? Hmmmm, burned valve maybe?? Hmmmm?? So I'm thinking about
this all the way home and the problem, at least it seems, gets even more
distinct. Definitely a problem, but maybe I set the front float too low, or
the idle screws need to be opened up a little richer, or?? I get home,
immediately pop the hood and use my screwdriver to check the fuel level and
play with the idle mixture. No help there. Next, I start pulling spark plug
wires one at a time. Hey what's this, scarcely any spark going to #1 plug
and no change in idle roughness either. Well, this could be real good news!
Maybe just a bad plug wire. Check the resistance versus another wire. 2.4k
ohms on both. Now I grab the spark plug wrench, being happy it's #1 and not
one of the harder to reach ones. (No generator over #1 on mine.) I pull out
what's left of an Autolite AP45 platinum plug; most of the ground electrode
gone and a hole in the center insulator where that electrode should be.
Can't help but wonder if those pieces managed to get passed the exhaust
valve without doing any damage. So, get the compression gauge and give it a
check; whew, 150 psig, just like it was 30k miles ago. Pop in a spare plug
and fire it up and it purrs - boy does it purr. And I'm thankful my neglect
hasn't had any more serious consequences. So, today I'm off to MMJ's for a
new set up plugs. Should I try these AP45s again or try something else?
Maybe a little cooler plug. I pulled #2 and it looked very clean - maybe
too clean. Never seen a plug this clean before; especially not after about
20k miles. Part of this is thanks to the new unleaded gas, but shouldn't
the center insulator be a LITTLE BIT discolored? Running too lean? Maybe
I'll go a size or two higher on the front jets and, oh yeah, still need to
check the fuel pump and filter. I guess downloading the latest beta version
of my Eudora e-mail will just have to wait till later.
TTFN,
Bob
Robert L. Palmer
Dept. of AMES, Univ. of Calif., San Diego
rpalmer@ames.ucsd.edu
rpalmer@cts.com
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