FlowScan low reading

[sonexbuilder553]

Hi all : After few hours of test flights of my D-180, I have got very low fuel flow readings. The starting K factor was the tag one (29050).To calibrate the FlowScan, I have performed a free fuel flow test on my carb port, measuring the true delivered fuel in 6 minutes versus the indicated instrument flow.
So I calculate a new K factor. It was near the half of the tag one.
With the new calculated K factor, I performed the test again and it was now perfect. I measured 9,3 liters delivered in 6 minutes and the D-180 reading was 91 liters/hour.
THE QUESTIONS: Is that a correct way to calibrate the FlowScan?
Is normal the new K calculated K factor? (near the half value of the indicated on the tag) or it is out of parameters.
Thanks in advance Miguel from Spain.

 

[dynonsupport]

That value on the tag is a measured value, so it should be close to correct. Being hooked up to your fuel plumbing can change the effective k-factor some, but 50% is a lot. If you went through the calibration procedure though, and it brought the readings back to correct, I'd leave it as-is. Engine vibration or fuel flow turbulence may account for your drastic change in k-factor needed.