Carb Problem
Thread Starter
Pro
Joined: Sep 2000
Posts: 535
Likes: 19
From: California
Carb Problem
Hello,
I just picked up a '67 Sunfire yellow smallblock coupe from a fellow CF member. The car runs and drives fine and needs a couple of things (carpet set, exhaust, etc.) and I've recently run across a problem that requires help from the knowledgeable C2 folks here on the forum.
The problem started when I floored the accellerator while driving up a long grade. Now the car starts hard, idles rough and gas is pooling on the intake underneath the front of the carb. Is this a symptom of a blown out power valve? If so can I just replace the power valve or should I go ahead and rebuild the carb? (I've never done this before, but I've found some good articles on the web on how to do this).
Thanks in advance for your help.
I just picked up a '67 Sunfire yellow smallblock coupe from a fellow CF member. The car runs and drives fine and needs a couple of things (carpet set, exhaust, etc.) and I've recently run across a problem that requires help from the knowledgeable C2 folks here on the forum.
The problem started when I floored the accellerator while driving up a long grade. Now the car starts hard, idles rough and gas is pooling on the intake underneath the front of the carb. Is this a symptom of a blown out power valve? If so can I just replace the power valve or should I go ahead and rebuild the carb? (I've never done this before, but I've found some good articles on the web on how to do this).
Thanks in advance for your help.
Tech Contributor
Joined: Aug 1999
Posts: 14,374
Likes: 6,373
From: At my Bar drinking and wrenching in Lafayette Colorado
Re: Carb Problem (USA1LT1)
I agree with Dave - a blown PV won't pool fuel on the manifold. You can easily check to see if you have a needle/seat problem by pulling the sight plug in the side of the bowl, placing a rag under the bowl area, and having someone start the engine briefly. If fuel pours out of the sight plug hole, you have fuel leaking by the needle/seat (so shut the engine off real quick...). The other way you can check this is to simply look down the primary venturi after engine shut-down: if you see fuel dribbling out of the main discharge nozzles after shutdown, you have a fuel level control problem that is most commonly attributed to a leaky needle/seat from a piece of debris. The fuel will dribble down onto the closed throttle plates after shutdown, siphon out of the throttle shafts, and drip onto the intake.
To fix it, just pop the primary float bowl off the carb and disassemble it. There aren't very many pieces. You might have to replace the gaskets if they're old. Blow out the needle and seat real good and slap it back together. It should work fine without buying a $40 Holley rebuild kit.
To fix it, just pop the primary float bowl off the carb and disassemble it. There aren't very many pieces. You might have to replace the gaskets if they're old. Blow out the needle and seat real good and slap it back together. It should work fine without buying a $40 Holley rebuild kit.
Melting Slicks
Joined: Aug 2000
Posts: 3,077
Likes: 2
From: The Garden Spot of the Garden State
Re: Carb Problem (Milehigh66)
...i want to add a different point...since you have had raw gas pooling in the mainfold, you may have washed the cylinder walls and diluted your crankcase oil...probably a good idea to also change your oil and filter...sounds like this hasn't beeno occuring for too long....btdt
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