1/4" adjustments are HUGE adjustments,so be careful with that. And it surprises me that your temp claimed to increase when running richer,it is supposed to drop because the added oil going into the engine should cool it more. With some engines....when you lean the low,you must richen the high a little to even it out(dont ask me why) and vise-versa. This means that sometimes when you adjust one setting it affects the other. This tends to really stump some people when tuning engines,particularly the cheaper ones that people claim cant be tuned. This may be the case with your engine. So,just keep this in mind when your tuning.

Also,I like to put a small piece of fuel tubing around the needle valve to help prevent difficult to find air leaks around the needle valve threads that you might not notice. This seems to work wonders on some engines too.