Hello, first time post longtime lurker, Have new to me 250 tundra that is very boggy on low end and low idle speed. gets worse as it warms up, i replaced fuel, fuel lines and cleaned carb, everything looked good and in specs. ran it and same problem. Low end boggy and would run out good when you worked the throttle over half. You have to work the throttle to get it up to clutch engagement speed. Removed and went threw carburetor again and replaced pilot and main jet.retried and no change.have good spark and new plug and ran on a stand with loose track. No change. Stumped. on a hunch i removed the muffler and ran engine. idles at 1500 rpm and throttle response was snappy and immediately responsive/ put pipe back on and idle drops back to 900 and boggy comes back, So i think i have it figured out. When i examine muffler and blow air threw it doesn't appear to be obstructed. Not sure how to inspect inside? I'm past the age where loud pipes are cool and want quiet sled. What should i do next???