Ellison TBI problems

Looking for help from anyone who has an Ellison throttle body injector on a Lycoming engine. During run up on takeoffs, my engine is hesitating as it accelerates around 1500-2000 RPM. After a few seconds it catches and accelerates to full power. Only does this on takeoff, not while airborne. Manual says the idle mixture could be too lean. I tried enriching several times and to get any improvement results in an unacceptable idle condition. Another potential problem according to the manual is a clogged spray bar. It seems ok the best I can tell but really need to send in to Ellison to verify. I have placed several calls (only answering machine) and sent emails to them with no replies. Maybe they closed due to the virus but right now I am at a standstill. Any help would be greatly appreciated.

Zem

I've seen this before on the Rotec TBI. It has a similar design. each time it was either a clogged spray bar or the last chance filter before the spray bar getting clogged.

Thanks! I did check the filter screen so it must be the spray bar. Unfortunately Ellison is the only service shop for them but their status is unknown.