Floats are correct and have fiddled with 'em up and down to no avail.
Revs don't drop upon hard braking (like I think you'd see with low
floats).
I have clear sight plugs and it looks good.
I tried timing from 6-8 at idle and tried total timing and it came back
to
roughly the same idle time. Today I used the vacuum gauge and best vacuum
gave 20+ idle timing. When I ran it up the road, surprise... ping! Just
backed off down to 15deg. We'll see how that fares without the vacuum
advance connected (and work from there).
Still, idle mixture screws are fairly unresponsive. I wonder if the
secondaries are open too far. But, if that were the case, wouldn't
closing
them a bit be an erred solution to different problem?
Drink
"jim" <"sjedgingN0sp"@[EMAIL PROTECTED]
> wrote in message
news:1171738743_1661@[EMAIL PROTECTED]
>
>
> James Drinkwater wrote:
>>
>> Hi Guys,
>> Got a Holley 650 double-pumper on "Dad's hotrod" with some probs
>> tuning.
>> Upon depression of the throttle, my fuel/air ratio gauge shows that the
>> mixture goes way lean and the engine goes into lean misfire and dropped
>> power. Eventually it richens back up as the RPMs slowly increase. Not
>> talking about the accelerator pump, just giving it a little more gas
>> while
>> driving.
>> Bought the carb from my machinist in the original box in like-new
>> (visually) condition. Here's what's new and ruled out: high-volume
fuel
>> pump, fuel filter, fuel regulator and pressure gauge, float needles &
>> seats,
>> jets (just to be sure), 6.5" power valve (like the original). both
>> squirters appear to pump fine but the problem occurs when you slowly
roll
>> into the throttle and it happens really quick (very throttle
sensitive).
>> It's a moderate, street performance SB Chevy that makes about 10.5"
>> vacuum
>> at idle. I know the PV should move up to 8.5" but rolling into heavy
>> acceleration (vacuum below PV opening point) doesn't overcome the lean
>> condition either.
>> Two last things are that idle mixture is pretty un-responsive to idle
>> mixture screws, even when idle speed is as low as the engine will
>> reliably
>> rev. Second, main jets were very, very rich at stock 67's (primary) and
>> still a tad on the rich side with 65's.
>> Dirty passage somewhere? Higher vacuum power valve needed and drill
>> the
>> PVCR's? I'm a little stumped.
>
> You didn't say anything about float adjustment. A low float level would
> match the description of the problem. Late ignition timing would also
> contribute to the problem.
>
> -jim
>
>> Best Regards,
>> Drink
>>
>> '87 TransAm (No computer controls)
>> Holley 650cfm double-pumper
>> Victor Jr. single plane
>> 186 heads, fully ****ted with 2.02 valves
>> 218/228 roller cam
>> 1.6 magnum rockers
>> 10:1 KB pistons
>> Mallory Comp9000 distributor
>> Hooker SuperComp headers
>> 3.73 gears
>
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