Ok, had some fun with spanners today. I swapped off the twin 94 setup that came with my car and reverted to a single 94, since it was two carbs to a single intake (with a 2-to-1 adaptor) and it didn't idle nicely or pull well at low revs. Fixed both of those problems immediately and it's now idling at a nice low battery draining speed. It's got a couple of niggly flat spots though and I'm sure I can jet them out because they feel like mixture. What are the jets on a 94? There are two small ones that pump when you open the throttle. I'm guessing these are the power valves that I've heard about. One carb has these stamped underneath with a backwards 7 and the other has them stamped on the top with 71, but both seem to be the same size and pump about the same amount. Are they the same and what's a good size for a '53 flattie? Then there are the two jets pointing down the middle of the barrels which I'm guessing are the main jets. How do you identify those and roughly what size should I have? When it's idling is it normal for those ones to drip? I thought not, so I'm wondering if the floats need setting? Anyone know what height they should be? Idle I've got sorted, the screws are a bit vague but I've sorted a nice slow idle and it's responsive immediately. Cheers in advance for your help Edit: the flattie is a German 3.9 which is a 239 I think? Same displacement as a French one but with a little moustache under the dynamo bracket
I'm no expert but did alittle research into these earlier this summer. I think part of your problem may be in your power valves. I think in sigle carb. applications the power valve is approx. a 7" valve. When you switch to dual carb.s that number needs to be cut in half so it would probably be like a 3.5" inch valve in both. I'd check that. Just a guess. Check out the Holley 94 social group. There should be links to articles that have answers for you there all grouped together for your perusal. Jay
the two that squirt are your accellerator nozzles and the two in the center of the throats are high speed clusters the main jets are in the float bowl and can be various sizes
Cool, thanks for help so far chaps. I think the guy I bought it off said one power valve was blanked off but since I couldn't locate it I don't know which carb ended up back on the car. Looks like I'll have to revisit this.
The power valve is screwed into the main body casting of the carb and can be accessed by removing the cast iron base. It is a large, 1" hex, screw in affair with a diaphragm in the centre. The main jets are located inside the bowl. When you take the lid off, you can see them. There used to be a really good how-to tune dual 94s on here written by 286merc. Unfortunately, he no longer frequents the forum, but with a bit of searching, you may find it. Here's one I found - it's not THEE thread I was referring to, but it has the text from the original in there: http://www.jalopyjournal.com/forum/showthread.php?t=32467
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