<VV> Appreciate some help with poor idle, stalling

[Frank DuVal]

I just (earlier in 2014) went through this with my 66 A/C sedan. It 
would idle fine, then after it got hot, stumble, stall, ping like crazy 
pulling away from a light, rough idle, etc. Then run OK for a while.

On the advise of an NVCC member, I rebuilt the carbs, but paid more 
attention to the idle circuit. Even though I soak the carbs in the 5 
gallon solution of good stuff,  after washing them out I put the idle 
mixture screw back in part way and shot aerosol carb cleaner through the 
ports. Some junk came out! They have been working great ever since. On a 
prior rebuild, I had the mixture screw out when I shot aerosol carb 
cleaner through the passages.

Old dog, new trick.

Frank DuVal

On 2/12/2015 1:08 PM, MarK Durham via VirtualVairs wrote:
> Bill, we don't like to see compression spreads any more than 20 psi apart,
> but, putting that aside because thre is nothing you can do about it accept
> for trying to adjust valves, it may make the engine a little rougher, but
> they usually run OK down into the 100's.
>
> I would suggest you pull the tops of the carbs and the idle circuit cluster
> out of the middle of each and make sure everything is clean.
>
> When I see that turning the idle mixture screw does nothing, it usually
> means there is no idle fuel flow, and the carb is adjusted to compensate.
> Case in point, you got good suction on one, which is probably OK, and none
> on the other, when you put your palm over the top of each.
>
>
>
> Mark Durham
> Hauser, Idaho
> 62 Monza coupe Red/Red 4 speed
>
> On Wed, Feb 11, 2015 at 10:32 PM, Bill H. via VirtualVairs <
> virtualvairs at corvair.org> wrote:
>
>>                                                                   B"H
>> Hi all:  I'm still having awful problems with my Monza when idling,
>> especially in Drive, where the idle is unsteady, rough, and the engine
>> frequently stalls unless I put her in Neutral.  She's a 66 Monza, 110, PG
>> with factory A/C.  The idle tends to be uneven, sometimes she'll surge,
>> then slow down.
>> So far, here's what I've done:
>> 1.  New plugs, NGK, gapped to .0302.  Carbs, rebuilt 2012 by Grant
>> Young3.  Fuel pressure, 3-5 lb to both carbs (best as I can determine,
>> gauge crapped out on me).  Stock fuel pump used, brand new.  Both carbs
>> getting gas from fuel lines.4.  Fuel tank drained, refilled with fresh gas,
>> drygas and octane booster.  Saved a bit of old gas in a jar, no water or
>> impurities found5.  Compression test:  Engine warm, throttle at WOT per
>> gauge instructions (all plugs out, coil wire grounded):
>>      #1 - 133    #2 - 129    #3 - 155    #4 - 135    #5 - 121    #6 - 130
>> Cylinder #3 is a bit high, and #5 is a bit low.  However all are with I
>> think within acceptable range.
>> 6.  At idle, in Neutral, when I put my hand over the throat of the left
>> carb, the suction is STRONG and the engine falters and stalls if I keep my
>> hand there.  Turning the idle mixture screw does have a minor affect on the
>> idle.
>> 7.  With my hand over the right carb, the suction is WEAK and the engine
>> actually smooths out and the idle speed increases.  Turning the idle
>> mixture screw all the way in or out does nothing to change the idle.
>> 8.  Removed both idle mixture screws, sprayed carb cleaner in the port,
>> replaced screws.  Tried revving the engine with my hand tightly over each
>> carb throat separately, with the hope that the surge of fuel might wash
>> dirt or debris from the idle circuit.  Didn't change idle at all.
>> 9.  Carbs are tight, both on the intake manifold, and the air horns are
>> tightly screwed to the carbs.
>> 10. Plug wires are in good shape, engine has Pertronix ignition system.
>> 11.  Observed small amount of fuel dripping from venturi cluster of each
>> carb.  Clark's tech said this is normal as long as it's coming from the
>> venturi cluster and it's only a small amount.