G-62 4+ gal. with Lawnboy at 32to1, mounted on 80 inch Lanier CAP, turning Zinger 22 6-10. Runs strong NEVER quits. Idle set first and takes power smoothly. No problems until instalation of velocity stack. Reset using tach, peaked at 7300 and backed down to 7200 and took off. almost immediately went extremely rich. Entered the pattern and it quit on final. Checked plug and it was wet so leaned out 1/8 and tried again. Same result, died on final. Turned stack every direction made no difference. Took stack off reset everything and all back to normal. Not that big a deal, just tiring to get a little better gas mileage. I am puzzled because all other G-62s around (stack exposed to the air stream and not exposed) run great with the stack. I've been doing this for a long time and I can't figure this one out! Thanks, Skip