EZGO 2 cycle drowning with fuel

[kv1370]

Hi all, I'm trying to solve a problem with my Mom's 2 cycle EZGO Marathon. I believe from the serial number that it's a 1984 and it has a Robin EC25-2PG 244cc engine. Over time, the cart has run worse and worse and finally got to the point that it won't generate enough power to go forward. It runs a little better in reverse. It starts right up but won't rev up and blows clouds of gray smoke. I took off the air filter and the element looked clean, but at the bottom of the housing there was an oily sludge. The cart is driven on dusty roads around a farm, so that's where the dirt came from. She mixes the gas and oil at a 128:1 ratio, so I am guessing that fuel is backing up from the carburetor into the intake air chamber, then the gas evaporates, leaving the oil. There is no difference in how it runs with or without the air filter installed.

I noticed that the adjustment screw on the carburetor was completely missing, so I've replaced the carburetor. She lives at an elevation of 6,000 feet so maybe the carburetor I bought isn't jetted correctly, but the new carb didn't change anything.

I removed the muffler and discovered that it had liquid (presumably gas) in it. I tried running the cart without the muffler and gas spits out of the exhaust pipe along with the dark smoke, and the cart runs the same.

I am not a mechanic and know very little about engines but have been searching forums trying to resolve the problem because there are no repair shops closer than 90 miles from where my Mom lives and we have no means of transporting the cart. I read that a broken reed valve can cause gas to backup into the breather and cause plug fouling (which is also happening), so I took the reed valve out and cleaned it. Nothing looked broken and there was no light showing through. I checked compression and got 95 in forward and 105 in reverse. I don't know if the overloading of fuel can cause poor compression and I don't know how accurate my gauge is. I took apart the forward/reverse switch and two sets of contacts showed signs of arcing. I cleaned everything and switched the bad contacts with the good ones to see if that made a difference in how it ran forward vs backwards, but nothing changed.

Searching the forum, I found that sometimes fuel in the exhaust is due to a broken diaphragm in the fuel pump. I disassembled my fuel pump and both diaphragms looked OK.

If anyone has any suggestions, I'd sure appreciate the help.