Brad,
I used to have a '72 GMC pickup w/ a straight 6 that had exactly the same
symptoms. It had a VERY sticky lifter that I surmised was not letting an
intake valve close completely, although I was amazed at that idea, given the
strength of valve springs. But I was desperate, so I replaced the lifters and
the problem went away completely.
If you are running a Holley, and you get a backfire through it, you are running
a big risk that you'll blow out your power valve. Maybe someone else can
explain that.
BTW, with my pickup, it would get real exciting. When it would backfire, the
choke butterfly would bend and stick shut. This would happen usually when I
really needed some acceleration to get onto a crowded freeway. So I'd find
myself on the shoulder of a crowded freeway at the end of an onramp with a
stalled truck. I kept a large bolt on the dash, so I could get out, take off
the air cleaner, whack the butterfly valve with the bolt to open it up and then
try to figure out how to get onto a crowded 75mph freeway with no runway and
try not to do it all over again. It was exciting.
Good luck.
Mark
-----Original Message-----
From: owner-alpines@autox.team.net [mailto:owner-alpines@autox.team.net]
Sent: Saturday, December 21, 2002 3:02 PM
To: tigers-digest@autox.team.net
Subject: Tigers Digest V1 #347
Date: Wed, 18 Dec 2002 14:13:56 -0500
From: "BPARLEE" <bparlee@cfl.rr.com>
Subject: FW: Popping back through Carb
Got a problem I need some help on.
I restored my Tiger about 5 years ago and it has run great for about 8K
miles now every time I ask the original 260 to make more then a little power
it pops back through the carb and in turn - loses power till I back off. It
idles fine with no strange noises and I can rev it up with no problems, as
long as there is no load. I have Stock everything except the coil which I
replaced in trying to solve this problem it is a off the self coil spec'd
for an early Mustang.
I have;
Rebuilt the carb
Checked timing
Checked the vacuum advance
Took apart and cleaned the distributor ( made sure the advance
mechanisms
were free and operating.
Changed the coil, cap, rotor, points and condenser
Checked over the wiring
+ all the normal stuff.
I have not; because they are hard to do with no engine compartment room
Done a compression test
Changed the plugs (Only 2k miles on them and the ones I took out looked
perfect and that was a pain)
I'm stumped and I don't want to go in to the engine unless that is the
problem.
What could be amiss that would make it pop through the carb only under load
that I missed?
What would make it pop through the carb only under load in general?
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