Help with new carb ...?

I've just put a new PICT-34 on my '71 SB, and I can't get the idle set correctly. I've turned the mixture screw in lightly to stop, and back out 2

1/2 turns. Using a dwell/tach, I've turned the mixture screw out until no further RPM gain was achieved, and then back in 1/2 turn from there.

The problem is, I'm idling at +- 1200 RPM, and turning the bypass screw to obtain a 900RPM idle makes the car run like crap.

I've checked as thoroughly as possible for potential vacuum leaks, and find none.

Any hints?

Thanks, Larry

Reply to
Larry St. Regis
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Is this a twin port setup? If so, examine the rubber boots connecting the center piece of the manifoild to the end pieces..

J.

Reply to
BergRace

It is a dual port, yes. I've felt around the boots and they don't appear to be split and the rubber is pliable. I will try the "carb cleaner around the boots" routine, tho.

Larry

Reply to
Larry St. Regis

I encountered a similar problem myself, but did not examine very closely, ended up reasoning I had burnt valve. Not to be, the right hand rubber boot was split underneath, allowing "false" air to be drawn in.

J.

Reply to
BergRace

I read something about some of these new carbs having faulty floats--they would absorb the fuel in the bowl and sink-causing the engine to flood. It might be worth checking out.

Reply to
Bugzilla

When I installed a new Bocar 34-3 carb on my car, it was plagued with a number of problems that caused poor idling/running.

Probably not what you would want to do with a new carb, but if the other suggestions don't yield an improvement, I would remove & rebuild (yes!) the new carb. Mine had a lot of what I guess was casting debris (fine sand?) in the fuel bowl. Buy a couple large cans of gumout carb cleaner and act like this new carb is 20 years old - completely disasssemble and clean thouroughly.

Buy a good quality rebuild kit and use everything that fits (the bocar gaskets are awful and on mine you could actually see seepage from the cover down the bowl side). The bocar o-rings for the 2 adjustment screws were already cracking when I removed them, even though the carb was only about 1 month old.

Also buy a good carb to manifold gasket. The one that came with mine was way too thin & flimsy. I bought 5 good ones from Rocky Mt., keeping the extras as spares.

Also, use JB weld, muffler cement or silicone on all the casting plugs to prevent either air or fuel leakage.

=================================

" ..... I ain't no bandleader!!"

Reply to
Jack Woltz

Or buy a German 34... :0)

J.

Reply to
BergRace

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