ORIGINAL: MinnFlyer
Actually, it sounds like the low end is rich.
If an engine's low end is rich, you go to idel, and has the fuel builds, the RPM go down.
I agree!
The Saitos run slobberingly rich just fine, but the symptom of this is as described, strange idle performance.
I went through exactly the same thing before someone taught me the error of my Saito tuning!
As suggested to me, his best bet is to crank the LS needle down just until the engine will not start at idle, then back off about 1/2 turn or so.
The Saitos run rich when other engines would conk out completely. This tends to confuse people used to other engines.
I've seen many people assume that Saitos were too lean because they were used to the characteristics of most other engines.