I have a rebuilt stromberg OS-1 that I want to put on my model T. Can anybody school me on how to calibrate it? Thank you.
If you talk to him nicely, Stan Howe is your man.
If your carb is similar enough to a Stromberg OF, these earlier threads might be of help:
The instructions for your Studebaker carburetor are in the 1920 Dykes manual. I bet it is online someplace. If not I can scan a copy this weekend for you Daniel.
Try Google books.
There are four adjustments.
First is the float level which should be correct if it was rebuilt correctly.
Second is the high speed adjustment. With the engine above idle, open the mixture knob closest to the fuel bowl until the engine begins to stumble from too much fuel. Close it one click at a time until the engine is running smoothly and will accelerate without stumbling.
Third. Adjust the idle speed to the lowest the engine will continue to run and then raise it slightly for a slow idle.
Fourth. Adjust the idle mixture -- the knob on top of the throat -- for best idle and no hesitation under acceleration.
Fifth. Check that the economizer -- if so equipped, not all OS-1's have the rod and pull fork -- is opening when the throttle is nearly closed and remains open at idle. It should not need any adjustment if it was correctly rebuild.
You may have to find a happy medium as the OS-1 is pretty big for a stock T engine.
Note that the high speed adjustment is "open for more fuel" and the idle adjustment is "open for less fuel" as it is an air bleed into the mix. The amount of fuel supplied to the feed is controlled by the size of the hole in the jet feeding it.
Thank you all so much, I really appreciate it. I will let you know how it goes.
I'm building a "poor mans rajo" and am planning to put this carb on it if it checks out.
Stan, do you have any information on the stromberg MB-2 902955 ? I am running it on a model A engine in my race car. I have had it running ok at times. I am having trouble mostly with mid range. It idles ok and runs strong at full throttle. After reading the above adjustments, possibly, this one adjusts similar. It runs best with the Idle mixture in tight. I am missing the float acorn nut. Float adjustment? where to start? Any help would be appreciated. Thanks
If it runs best with the idle mixture in tight the feed passage to the idle is partially plugged. The idle jet is a fixed size, the knob adds or takes away air to the mix. Remove the idle tube and drill the jet one step at a time until it will idle with the mixture open at least 1/4 of a turn.
An MB-2 is pretty big for a Model A engine. You may not be moving enough air at mid range for it to run right.
Thanks Stan, I'll give it a try, any advice on setting the float level? I see how it adjusts just, wondering where to set it.
The Dykes manual helps a lot: