Doc

Would you like to explain, how You use vacuum gauge to at figure out correct spring tension for power valve. I've been thinking that maybe I'll have tired out sping there, because my a/f ratio is fluctuating very much at steady cruising.

Joug

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Sorry, my english is not very good

To set the step-up piston spring I have an old carb. body with a hose fitting attached.
With the spring & piston installed, I "T" in my vacuum gauge and draw a vacuum. I find the point where the spring / piston overcome the vacuum, as indicated on the guage.
To set a different enrichment point, change or adjust the spring tension.
DD

Sorry, but I don't understand. You have carb not installed in engine? From where you draw vacuum? At what point the spring should overcome in stock engine?

Joug

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Sorry, my english is not very good

Yes, I actually have a piece of an old carb. which I made into a step-up spring tester. I will take a photo of it to post.

I get the vacuum either off the engine or from a vacuum pump.

For a stock SL6 the step-up rods should start to pull out of the main jets at about 10 inches of vacuum.
DD

I meant that where You draw vacuum from that carb you are using.

I'll have to find out where I can get new springs for my carb. Maybe it's possible to at stretch old spring, but is there any coming back, if it's not working.
I hope that this could be the way to make my carb work better . I can lift metering rods, but it only makes mixture fluctuating more and lowers mileage. and with factory settings mixture is lean.

Joug

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Sorry, my english is not very good

Is there any shop that sells jets, metering rods and power valve springs for carter bbd????

Or is there any other springs that are suitable for that power valve?

Joug

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Sorry, my english is not very good

I have never tried to buy the jets / rods for the BBD seeing I already have a lot of extra pieces.

Here is a photo of the step-up spring adjustment fixture, it is a section of a carburetor with a hose bib epoxyed-in. I take a long section of hose and connect it to where the choke pull-off hose connects to the carb. I route the hose into the car and I can watch how the spring / step-up rod reacts to throttle. You will see that I also have a section cut from the floor jet so I can see how the rod fills the floor jet opening.

Once I have all the parts set correctly, I open-up the carb and install the combination of parts into it.
It is kind of a cool tool because it let's you see what is going-on inside your carb.
DD

That's very cool and simple way to check springs. My problem is that I don't have spare carbs for parts and I don't know where to buy different springs.

That tool you have made is from older type of bbd. Are those springs similar than newer carters?

Joug

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Sorry, my english is not very good