Re: [ihc] Age Old Carb Questions

["Allan Ericson" <lowvolt@xxxxxxxxxxxx>]

Michael-

Check to see that the plugs are all in the right order.

Check to see that the timing is advancing with rpm, and that it's stable. A
wobbly shaft or defective vacuum advance can cause instability.

Check to see that the vacuum advance is working properly, which includes the
timing staying put. Sometimes the diaphragm cracks, which makes the timing
advance and then retard, which results in a rough run.

Make sure the ported vacuum is really ported. No vacuum at idle is proper.

Backfire from the carb is usually caused by the timing being too far
advanced, although crossfiring or miswired plugs can do the same thing.

I left a few things out, but I can't remember what they are. Must have
coffee, must have coffee, must.....

----- Original Message ----- 
From: "Joseph Shaw, II" <josephshaw@domain.elided>
To: <ihc@domain.elided>
Sent: Wednesday, October 01, 2003 5:13 AM
Subject: [ihc] Age Old Carb Questions


> Okay, regarding my recent acquaition '75 Scout II (345, Auto, 2WD), I have
> re-timed, installed a new fuel pump, new plugs and wires, etc.  However,
since
> installing the new fuel pump, and thinking, NOW I likely have it working,
I
> should REALLY do it right, and thus, RE-setting the air gap, trying to
time
> it, etc, it is not running as well as I had it running at some points
before.
> It WILL start on its own now, which it wasn't doing before (needed a
little
> priming), but runs rougher, lots of small sputters and backfires through
the
> carb, etc.  I have tweaked the timing a million times, in each direction,
and
> have not been able to make it better, and it is not quite running well
enough
> to get out and check the timing with the light to make SURE of where it
needs
> to go before I try something else-here is my current thinking-wondering
what
> anyone thinks of this:
>
> I did notice that when disconnecting the vacuum line from the carb base to
the
> dist that it was fairly loose, with enlarged ends.  It has come off of its
own
> accord since this process began.  Thus, I am replacing that vacuum line
today,
> but could a small vacuum line from that port cause such a reaction?
>
> Just curious-it didn't sputter this bad or run this poorly when I had the
> vacuum line disconnected to time it before, so don't see why it should run
> that bad with partial vcacuum either.
>
> Thanks for any input-I'll let you know how it turns out!
>
> And for the record-I DO know the whole timing procedure from scratch, but
> since I had it running failr well before, and could see/hear how the
timing
> affected it, I KNOW that it is within the timing general area-HATE to go
to
> all of that work (no one around to help with turning it over while I feel
for
> vacuum or pressure, etc) when I am quite confident it doesn't need that
> specific of a re-time.
>
> Michael