My "new" round top carbs that I just put on my L26 want to redline constantly. I've gone thru the Haynes set up including:

*backing off throttle adjust screws

*closing mixture and then back out 1.5 turns

*choke is off

I'm missing the springs which I assume attach down to the heat shield somewhere but have the linkage secured in the closed position for throttle.

Also what does the hose fitting on the Float bowl go to? I had it just open as assumed would go to air filter, but then blocked it off to make sure wasn't causing problems. It's the one located kind of in the centre of the top plate

The hose fitting on the float bowl is an overflow that normally goes to the air cleaner, which is supposed to keep fuel from dripping onto the hot exhaust manifold. In reality, it doesn't make much difference.

Okay thanks. Could anything be faulty with them that might cause this?

Well I sorted it out. Feel like a bit of a goose but a happy one. ::

Turns out the new manifold is slightly different so that the linkage that runs across the firewall had to be adjusted out about 10mm because it was holding throttle open just a little. Quite surprised because had my finger inside carby and felt them earlier on the piece and must have only been open a bees ****. That's why I didn't suspect that was the problem. Now just need some springs tomorrow and air filter and I'm in business. Sounds great already, can't believe the difference, running so smooth and haven't even tried to adjust properly.

"Also what does the hose fitting on the Float bowl go to? I had it just open as assumed would go to air filter, but then blocked it off to make sure wasn't causing problems. It's the one located kind of in the centre of the top plate"

From what I gathered from the ZTherapy video that overflow fitting also acts as a vent to equalize the presure in the bowl allowing a consistant float level and thus a consistant fuel ratio. It will run with it capped off but not optimaly.

If you can't pipe it into your air cleaner set up, pipe it somewhere so it can still breathe. Just not anywhere near the manifold/exhaust in case it does overflow.

Steve