Stromberg 97 adjust
 

I have two Stromberg 97 carbs on my 59ab. Trying to adjust the idle mixture screws. Is there a special screwdriver needed? Do I have to take the carburetors off to accomplish this? Looking for a 90° flexible screwdriver to do this. Any advice or ideas is appreciated. Thanks in advance King's kid.

Re: Stromberg 97 adjust
 

They should be able to turn by finger pressure... if tight you can use a washer to fit in the slot to turn them.

Re: Stromberg 97 adjust
 

Offset driver

Re: Stromberg 97 adjust
 

I've got a special screwdriver designed just for this purpose somewhere. It has a cylinder shaped piece over the slotted part that holds it on the adjusting screw so it doesn't slip off. It is on the end of a flexible shaft (kinda like a speedometer cable) with a nob on the other end. I'll try to find it an post pictures. A "Google" search may yield the same thing quicker.

EDIT : Try this : https://www.amazon.com/OEMTOOLS-2506...1484361&sr=8-5.

Re: Stromberg 97 adjust
 

Maybe he has some originals with no slots?

Re: Stromberg 97 adjust
 

A little trick I learned on here with twin 97's, is to find some rubber hose that slips snugly over the heads of those mixture screws, cut to suitable length to be able to access.

Re: Stromberg 97 adjust
 

The original screws have a slot almost half way across the head.

Re: Stromberg 97 adjust
 

Years ago I bought some that had knurled heads you can grab with your fingers instead of slotted for a screwdriver. I could swear they came from Uncle Max. If he doesn't still have them he would sure know where to get them.

Re: Stromberg 97 adjust
 

Re: Stromberg 97 adjust
 

Thanks for the replies. I was able to use clear plastic tubing over the screws.
Two duce set up too close to get hand in there. What is the correct setting on these? Many different suggestions. From 1/2 - 1 1/2?
As you can tell I'm new to this. Was checking the carbs off the car- one has throttle plates in the base, the other one doesn't. What's up with that? I just got the car 47 Bus. coupe. Running real rich. Offy. heads and intake, 2- 97's,
Isky #77 cam, Fenton cast iron headers. suggestions? Thanks, kingskid.

Re: Stromberg 97 adjust
 

Max's design is just enough longer so your thumb and fore finger are the only tools required.
Charlie ny

Re: Stromberg 97 adjust
 

Both MUST have throttle plates!!! With two 97's the adjustment is about 1 1/2 turn out. Are you running the Carbs with linkage synced or progressive? Typically synced is good. You may need a Uni-Syn or similar gauge to monitor the air through the two Carbs at idle to adjust each so they work together equally. The idle vacuum will be lower with two Carbs about 15"

Re: Stromberg 97 adjust
 

You're kidding right? How does it even run with no throttle plates in one carb? WAY TOO MUCH air getting in with not enough gas. You must mean choke plate I assume.

Re: Stromberg 97 adjust
 

Ditto

Re: Stromberg 97 adjust
 

No, not kidding. I thought to myself "how does it even run"? I used some rubber hose and got the mixture set. Pulling 16" of vacuum at idle. I thought that was in limits considering the cam. Still baffled about the throttle plates. There is throttle plates in the carb, but not the base. That is the front carb which should be the secondary right? I'm using synced linkage. Hard to start when warmed up. Cooled down starts right up 1-2 Rev's.

Re: Stromberg 97 adjust
 

The synced Carbs are both operated at the same time by the linkage with both operating together at idle. Neither is considered secondary and both Carbs should be identical. For example tri-power that is set up progressive, the front and rear Carbs are secondary since they no not operate at idle

Your front carb is a dummy, it is there for appearance and to block the holes in the manifold. The throttle plates in the cast iron base were removed so a plate could be installed to block any air from going through the Car. You should also find no fuel going to the front Carb. When your car is running you should be able to place your hand over the front Carb and nothing will happen, the engine will continue to idle. On the front carb, take both idle adjustment screws and screw then in all the way and adjust the idle mixture with just the rear carb.

Just the rear Carb is working and it may not be set up properly resulting in improper idle adjustment and poor operation being rich. I would think the idle mixture screws should be out about 1 turn or slightly less not 1/4 turn. Your vacuum should be closer to 20" For a 97 I believe you want .045 mains and #65 power valve. If you want both Carb to operate there is a lot more to be done.

Re: Stromberg 97 adjust
 

What manifold do you have on the engine? Most 2-carb manifolds should have two fully functional carbs - no dummy in either location. If you only run one carb, you can get really uneven fuel distribution to the cylinders that are furthest away.

Re: Stromberg 97 adjust
 

If you have one of this type dual manifolds, you can probably get away with running one carb blocked off (the rear carb), as the front carb is in just about the position as a stock manifold. It's better to get two running correctly, though

Re: Stromberg 97 adjust
 

Forgive me for entering your thread but I have a couple questions that if answered might help you as well to get your carbs sorted.
What mainjets would you run in a twin (GB) Stromberg 97 carb set-up? The reason I ask is that I am not getting info anywhere. No response from the makers in GB so far. The engine is running rich and smells badly.
What I did until now:
lowered pressure to 2,5 psi
lowered fuellevel 1/8" below the recommended 1/2" level
fitted smaller mainjets (around 0,040")
adjusted the idle with the mixture screws, have nice and even tick-over and good response to the pedal.

Are the mainjets really responsible over almost the whole rev range? I want to lean the carbs out a bit more and will make a couple smaller jets on my lathe to try.
Thanks for any wisdom you could share with me

Re: Stromberg 97 adjust
 

Vincent, I wish I knew enough to answer your questions. I am not very familiar with the 97's. I had Holley's on my fifty. I think Terry,OH answered my situation. The car runs fine under acceleration. I just wondered why no butter fly's in the one base. Never seen that before. Thanks for your reply.