I have done a fairly hefty piece of investigaion on getting an Ellison to work properly on a Tigre IVb (the V seems much less sensitive).
 
I have uploaded a draft report which I am happy to share with the forum for feedback on the basis that it is an illustrative and not definitive, partially informed view.
 
My conclusion is to have an inlet plenum and tapered spacer made up and then try and fine tune the mixture jet once this has been completed.
 
Hope this is of interest
 
Ian

tigredata.jpg

Click on the image above to see the full report.