Two 97's Set Up

[Shoebox]

I know it's been discussed to death, but for me it's been awhile. Got two new Stromberg 97's from Max and straight linkage. I've read that one should use the rear carb for throttle linkage idle control and have the front idle screw all the way out OR removed, and have the rear carb and related linkage control throttle plate position. Perhaps it makes sense however in my past success I used both idle screws (not talking about idle MIXTURE screws) in this process. What say you guru guys? Thanks much.

 

[alchemy]

Use both screws. So the screw is the positive stop, not the linkage.

 

[Flathead Fever]

Both carbs should be adjusted the same. Disconnect the linkage and adjust both carbs the same exact amount. Set the idle speed screws the same amount until you get the correct idle speed. They will both be set just barely open, the "exact" same amount Then set the idle mixture screws the same number of turns, maybe by starting at 1 1/2 turns out each on bith carbs, then adjust them in exactly the same amount until the engines starts to slow and then back them out until it smooths out. Both carbs should be adjusted the same amount. Then go back and reset the idle speed. Then you might have to go back and reset the idle mixture screws. When your done both carbs will be set "exactly" the same amount. Then hook the linkage back up without moving the throttle blades and then make sure both carbs are opening all the way up at full throttle. Everything should be adjusted "exactly" the same amount on both carbs.

I use a bottle of propane to set the idle mixture, if I give it a little propane and the idle goes up it's too lean, if it goes down it's too rich. I go back and forth between the two carbs until the idle doesn't change with the addition of the propane (a little bit of propane). When your done the idle speed screws will be turned out exactly the same amount and the idle mixture screws will be turned out exactly the same amount on "both" carbs. It's like you're adjusting one carb that's just split in half

 

[Ziggster]

I can only speak as to what I did with my dual 94s on a vintage Edmund’s intake. Since my intake kept the generator in the stk location along with the forward carb position, I decided to go with a progressive linkage with the rear carb acting as a secondary. Lots of folks said it wouldn’t work, but based on some initial testing/running without actually driving it yet, it works fine. I had issues to get the secondary carb from sucking fuel in from the main circuit at idle, due to the idle being too high initially.
If you have an intake where you cannot mount the generator in the stk location, then I would go for a straight/direct linkage setup. To further tune the carbs, I would get a uni-syn ball style flow meter to balance the carbs properly.

A short vid of my carb setup and engine idling and at about 3/4 throttle.

https://youtube.com/shorts/x6332ssgBfI?si=PnCn4v5qGwAZHeN3

 

[tubman]

I can only speak as to what I did with my dual 94s on a vintage Edmund’s intake.........based on some initial testing/running without actually driving it yet, it works fine.........

It is my opinion that these manifolds were designed to be run this way. I remember when I was a kid in the '50's and '60's, "progressive linkage" was a big deal when adding dual carbs.

 

[V8 Bob]

The first dual intake I used on my stock '51 239 was an Edmund's regular that allows stock generator location. I set it up with identical 94s straight linked and it ran very well in my normal driving. The only issue for me was the rather odd (looking) carb spacing, so it was eventually replaced with a more conventional Edelbrock regular dual, also straight linked. IMO, the Edmund's carb spacing would favor straight linkage over progressive.


I think the main reason progressive linkage was popular early on was possibly better mileage for normal everyday usage. However, I ran the '51 for a couple years with the stock single intake/ 94, and have never seen a significant mileage drop running dual carbs with straight linkage for the last 20 years. I think many will find it easier to set up a dual setup straight linked vs progressive. The main key is having both carbs (94s or 97s) exactly the same.