need help with this one.

Is there anything in your throttle system that could be causing an intermittent carb imbalance?

Check that the carburetor piston slides up/down freely if not it can cause an out of sync condition, if they do not clean and lube the shaft and bushing with engine oil. Also verify the rubber carburetor mounting flange is in good condition, especially after violent shaking from being out of sync.

Yesterday I did the the syringe testing method to see how much fuel it would take to make it run out the over flow tube. This method is explained in SB-912-065ul.

I found it only took 20 ML to overflow. So I set the flow level down and retested and got 30 ML. The Rotax SB says the correct range is 23 to 40 ML

Originally I set the float level to spec by measurement's only when I put new valve ,floats and bracket in. So my test yesterday showed the float level to high.

I will be doing some test running to see how that goes.

carb pistons in good shape and smooth movement. I made sure of that when I replaced the diaphragms also no intermittent sync problems.