<VV> Buick 215 troubleshooting question (No Corvair)

[Andy Clark]

Bill, my guess is a bad vacuum line. If the car has sat all that time, the
rubber has probably deteriorated and cracked. Finding it may be time
consuming. Were I you I'd replace them all. Old vacuum lines can be a PITA
and leaky ones can produce just exactly the symptoms you describe. The
vacuum leak is much more noticeable at light throttle (high manifold vacuum)
than it is when you are accelerating or running at higher speed (lower
manifold vacuum). HTH.
Andy Clark
Camano Island, WA.
66 140/4 Monza Sedan
66 140/4 Stinger Clone
66 180/4 Cord 8/10 #60
----- Original Message ----- 
From: "Bill Elliott" <corvair at fnader.com>
To: "Virtual Vairs" <virtualvairs at corvair.org>
Sent: Friday, January 20, 2006 7:27 PM
Subject: <VV> Buick 215 troubleshooting question (No Corvair)


> Hi gang... I have a really stupid question... but since you all may have
> run into this combination before, possibly somebody can suggest where to
> look next.
>
> Subject is a 1963 Buick 215 with a warm cam, roller rockers, headers,
> etc and a Carter AFB 400cfm on an aftermarket manifold. Stock 1963 Buick
> ignition (except no vacuum advance, so I assume a recurved dizzy),
> manual transmission.
>
> Car sat for several years, started and driven only occasionally since
1990.
>
> Car starts and idles fine, but as soon as you place any load on the
> engine with light throttle it falters and bucks. Put your foot into it
> and it catches and pulls away very strongly. Driving along, if you give
> it just a little throttle, it bucks and falters... give her more
> throttle and she runs great.
>
> First thing I did was to pull the carb off. The carb looked nice and
> clean, but it appeared there was some water in the gas.  Just to be
> sure, I sent the carb out to a local pro for him to check it over and
> rebuild. He reported that it was nearly new, had a little sediment here
> and there, but overall looked good. He went ahead and rebuilt and
> adjusted it for me.
>
> I drained the tank on the car, flushed it and the lines out good, and
> put fresh fuel in. I popped the distributor and the points looked nice
> and clean, cap and rotor nearly near, and the advance mechanism seemed
> to be free and clean.
>
> Put everything back together and she runs EXACTLY the same way.
>
> It would seem to me that possibly the primaries aren't flowing enough
> fuel...and only when you get the fuel from the secondaries does it pull
> well. BUT, even if the carb had never been set up for the engine, you'd
> think off the shelf it would run better than that... and if the car was
> running _only_ on the fuel from the secondaries, it would still be way
> lean (which it does not seem to be).
>
> I have the same basic carb on a Dodge 273 and that engine has a lot more
> low end than top end... no carb worries at all.
>
> Is there something else I should consider before replacing the carb? I'm
> REALLY thinking ignition... but due to the engine placement (Esprit S1),
> it's very difficult to check timing and advance. I know from my British
> cars that 90% of carb problems are really Lucas in nature...
>
> Thanks!
> Bill Elliott