Small Engines (Lawn Mowers, etc.): Toro Model 20684 GTS 2-Stroke Suzuki Mower, starter rope, air leak

Question
I've had my Toro Model 20684 GTS (Suzuki 2-stroke) Mower new since 1988 and I never even changed the spark plug until yesterday. I am loosing power when it needs it and I can't understand why. It still starts in 2 or 3 pulls, the compression seems ok by the way it feels when I pull the starter rope, no scoring observed thru the intake port, (I have not checked the exhaust port yet), I rebuilt the carb yesterday because the inside diameter of the fuel line was grossly deteriorated, causing particles of rubber to clog the inlet to the carb. Interestingly the manual states no ethanol should be used because damage to the fuel system can result, I wonder if this was the cause for the grossly deteriorated fuel line? (All the gas around here states up to 10% ethanol!). The only issue with the rebuild is the governor setting, I need to figure out how to set that so the idle is back to low rpm as normal, not it seems to be left to cut speed if you know what I mean. My mistake was not to mark the relative position between the governor shaft and the governor arm, (any help anyone?). Well it looses power when it needs it, higher grass, and it is so frustrating, It runs great under no load. I believe the lower crank bearing is going because I can hear a knock of late that is not normal, like the knock you may hear when the bag gets full and the blade is hammering away at a grass clog, but it knocks when it is clear. I wonder if there can be an air leak by the lower bearing that cause its lose of power, but I also believe an air leak will likely cause it to seize up, so I am stumped. Is there anyone out there who can help me out? It's been a great unit but I refuse to believe it has reached the end of its service life! Help!!!!!!!!!!

Answer
 Hello Dominick:

 Check the Exhaust Port for Blockage before going any further. Send me the Model Numbers Off of the Engine, Please. With these Number I can Locate a Breakdown of the Engine and Better Assist you. However, If the Lower Bearing is Noisy then you are more than likely going to have to Replace this before you can get the Unit Running Properly. This can also be Part of the Carburator Problem. On 2cycle Engines, ALL the Bearings and Seals Must be in Good Condition or they will cause Other Problems. Ths Ethanol causes the Fuel Line to Deteriorate Faster than Usual. Depending on How Much Use this Mower has Had you have Gotten More Use out of this Engine than Others I have known. Most times this Engine will Last 4 to 6 years before giving Minor Problems. Major Problems Occur at about 10 to 12 yrs. Hope this Helps. I am here if you Require more Assistance. Let me know what Happens, Please. I enjoy knowing the Outcome. Thanks.

 Good Luck

 Respectfully

 John