The Thunder Tiger carb has a couple issues, (no throttle stop and won't run without muffler pressure). I hear the fix is to just replace it with a Perry. Not wanting to spend $40.00 on a carb for an airplane that might get flown 5 or 6 times a year I started thinking about what could done to the stock carb to over come it's deficiencies.
First was the throttle stop.. A piece of 5/8 round aluminum stock, a 2-56 screw and spring was all that was needed to solve the first issue. Made an aluminum washer that fit over the shoulder machined into the barrel behind the throttle lever. It's 0.06" thick which is just enough to capture it when the lever is bolted down. Turning in the screw will stop the barrel from moving into the body and effectively becomes a throttle stop.
To address the second item I removed the spray bar (needle housing) and determined what size drill was needed to miss the internal threads. Chucked the housing in my lathe and drilled the needle seat in about 1/8 inch. The needle housing has a couple holes for the fuel to get into the carb and I just went far enough to be able to see the tip of the drill through the holes. I then deburred and cleaned it to be sure all the chips were removed.
The theory is that by moving the needle seat in, the needle should need to be screwed in further to achieve the same mixture as before. Hoping this will solve the problem of the needle being almost all the way out of the threads to get a good setting.
Hoping to be able to put the engine on the test stand today to see if it all works.. Really see no reason it work like a charm..