Rotax pre-evo carb question

Hey guys, gonna be asking almost all of you to dig deep in the memory banks here as I know pre-evo rotax is much a thing of the past.

So basically the pre-evo senior carb had two specifications

Venturi: 12.5
Idle jets: 30/30
Floats: 5.2g


Venturi: 8.5
Idle jets: 60/60
Floats: 3.6g

I have one of the 8.5 carbs but I’ve been told by guys out of the UK that the seniors prefer the 5.2g floats, so I switched to those but still running the 8.5 venturi and 60/60 idles. I have no intention of changing the venturi, but would there be any benefit in changing the idles out to the 30/30s ?

I am no expert but i would think that you are now extremely rich and jetting charts will be way off . I prefer the lighter floats and larger idle are they block less and run a bit smoother. I would think your not legal if you were racing . Its one setup or the other i sure some people mix and match but thats a bit tricky. We also run rok and when you change one thing it affects others. Hope this is helpful

Jessie well this is exactly what I’m noticing, my jetting is really weirdly off vs the other guys, i am like 3 jets richer for my engine to run and not pop

Just put it back how it was or get an xs evo carb , the new carb stops alot of that jumping when you floor it .

Ok gottcha. Did yours ever idle btw? Mine doesn’t for the life of it no matter what

Never had a problem with rotax idle , a have had problems top end or missing.

Ok thanks for the info bro