suggest returning to 5 deg BTDC @ 900 rpm (stabilizer bypassed). remember,
as engine surges centrifical and vacuum advance come into play, so
significant part of timing jitter with stabilizer back in circuit may not
actually be due to the stabilizer itself. idle may actualy be better at
stock 5 deg ATDC initial timing, but van will run much better and offer
better mpg with advanced setting. you may want to  bypass stabilizer and
adjust initial timing to about 14 deg BTC @ 900 and see how the van runs
leaving stabilizer bypassed - probably very well.

dlk

On Tue, 27 Jan 2004 12:52:07 -0800, Mike D. <md03@XOCHI.COM> wrote:

>I finally bought a digital timing light.  Followed the Bentley
>procedure (more or less):
>
>1. Disconnected the idle stabilizer and plugged the two plugs together
>2. Loosened the distributor locknut
>3. Started the engine, adjusted timing to 5 BTDC
>4. Adjusted the idle screw to get an idle around 900rpm.  The idle
>was not rock solid, but reasonably smooth.
>5. Checked the timing again -- still at 5BTDC
>
>Then,
>
>5. Stopped the engine, plugged the idle stabilizer back in, started it up.
>6. Yikes -- the 5 degrees BTDC timing jumped to about 10-15 BTDC, and
>the idle was very fast and surging.
>7. Readjusted the distributor to get timing approximately 5BTDC (*)
>8. Adjusted the idle screw to around 950rpm.
>
>(*) The idle is rough, and I can see the timing jumping around as the
>idle stabilizer advances it.
>
>So this has me worried -- if the timing and idle are OK without the
>idle stabilizer in circuit, why should putting it back in cause the
>timing to advance 5 or 10 degrees?   Is this the symptom of a bad
>idle stabilizer?