I have turned the screws on both sides from the stop out 1 1/2 turns. I put the vacuum gauge on it and got it up to 16. Then started to stink again out the back. If I leave it at the 1 1/2 turns it runs better. When I put it in gear I have to keep tapping on the peddle to keep it running.I have a 1" insert under the carb with a gasket under, and above the insert. I just changed all of the plugs. It starts right away. It just does not want to idle well in park, nor in Drive with the Brake on. I have checked for leaks with the propane, and there was no increase in rpms. Running the vacuum gauge off the intake I get a steady 18 How can I get this set up?? Thanks..
So is it 16 or 18? Adjust the idle mixture screws for the most inches of vacuum. If it won't idle, then look at the timing or adjust the idle speed adjustment screw.
In your other post that got locked you said it stinks up the garage. I'd check the float levels and maybe excessive fuel pressure.
after spending a good part of yesterday watching youtube vids on carb set-up, tuning & trouble-shooting a very common theme in almost all of them was measuring and making sure your fuel pressure was to carb specs. A number of vids said the same thing - if your fuel pressure isn't right, it messes with all the carb circuits.
Holley told me that if you have a mechanical pump. They are low pressure, and I DO'T need a fuel pressure gauge..
Carb is new. Bought it last year. If I adjust it up to 18 it smokes and stinks. If I lower it to the turn and a half it doesn't smoke or stink..
I rebuilt a List-1850-2 600 Holley and had the motor (Ford 302) idling @350 rpm and pulling 22-23 inches of vacuum.... I still have that carb...
Don’t Holly idle mixture screws work backwards? In is richer? I am a WCFB and AFB man so have extremely little knowledge of the Holly carbs.
Timing....timing...timing... Tell us about your timing curve. initial....total and @ what RPM. It all works together. With enough info we should be able to "fix-it" 6sally6
Some of the manual pumps, several Carters I've seen, can put out 7.5 psi. Make sure the primary throttle blades aren't letting to much of the transition slot to be exposed, it'll pull extra fuel in at idle and make it rich.
I've had to put a regulator after a mechanical pump. It's cheap and easy to check the pressure. Mine showed nearly 8lbs before I installed a reg...carb issues solved.
As far as the rest of it goes. I really don't know much about carbruators, or timming. I'll have to watch a few more videos on youtube.
They are supposed to be low pressure. Lots of defective shit out there these days. Have you actually measured the output pressure? Your vacuum gauge does this too! Don't guess, measure. For most carburetor a static pressure of 5 psi is plenty. More is not better. Then when you've verified that, set the float height carefully. Ever notice the fuel height is spec'd +/- a 32nd in.? A lot of "carburetor problems" though are often ignition timing related, or other engine defects, 16" is a tell, that's too low for Minnesota unless maybe you've a performance camshaft. A high steady manifold vacuum is pretty important for a carburetor to work right on a stock or street driven engine. The carb circuits utilize manifold vacuum particularly for smooth idle and a crisp, just off idle acceleration, up to about 35 mph where a lot of driving is done. If compression is acceptable and the engine not too lunched overall it should pull 19" to 21" at factory idle and ignition timing settings. If it doesn't, find out why, because you'll pull your hair out dinking around with the carburetor and it will never run quite right..
Still putting my money on the power valve. I've always had your same issue with Holley carbs, to the point that i switched to edelbrock. If you turn the mixture screws all the way in and it dies, the power valve isn't blown, but it's still more than likely opening up at idle. You can buy a set of different sizes cheap ($35) and switch them out until you find the one your engine wants. Here's a good read on it... https://www.holley.com/blog/post/holley_power_valve_tuning/
On your other thread you talked about "vacuum", so here are some exerpts from a book that should help you insure that vacuum is not the root culprit. Anyone working on some of the older engines and doesn't have much experience might want to chase down a copy of one of these books. They are basically the same, and Ebay currently has several available for about $5/$10.
Thanks. I will look for the book, and read. I stopped by a make shift car show, and was talking with a guy with Twin Holley 600's on a tunnel ram. He also said probably wasn't the carb. He said because I have never taken it out on the road, and driven it, and it has kind of a rough idle that it might be a sticky valve. Told me to get a bottle of Marvel oil. Drop have in the oil, and the other half in the gas. Said it won't hurt anything, and may help it. At least it will take care of any sticky valve issues. I put in a bottle in. I ran it for about a minute, and let it sit. Then I went out about 20 minutes later. Started it up. It smoked a little, but seemed to run smoother. Still has a rough sound with it, but it does have a cam in it. The engine came from a Circle Track Racer.. It was rebuilt. Put into a pickup truck, then it came with the car when I bought it. I can't take the car out to drive it yet, because I have the front up on blocks because I am waiting for a new power steering hose. After that I Will take it out and see how it handles..
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