Small Engines (Lawn Mowers, etc.): MTD 10hp chipper leaking gas from carb, cast iron engines, float valve

Question
Hi,

I have a MTD 10hp chipper w/ a Tecumsah Model HM100-159287U engine I inherited from my father.  It had been sitting for approx. 2yrs but prior to that started w/o difficulty and was only used maybe a dozen times.  I attempted to start it this weekend.  long story short. I was able to get it to run briefly using a little starter spray but then it would immediately cut off.  I pulled the cup off the bottom of the carb to see if it was getting gas.  It was a little difficult to take off but I did see it was full of gas.  Put it back on a lo and behold it started right up but soon choked itself off.  Unfortunately and here is my question.  I noticed gas began to leak out of the filter cover/carb.  I took the cup back off and reset it thinking maybe the float valve was stuck but gas continues to pour out like the float valve is stuck or something?  When I hold the float up with my finger the gas stops. When I set it upright gas just continues to leak out of the carburetor.  Is it a faulty float valve or did I damage something when I took the cup off? Would buying and replacing the float valve do the trick or is it a more involved problem? One other thing I noticed was the bolt holding the cup in place is hollow and a small plastic piece sits inside and it appears that it is broken?  Was there a plastic pin that set in there that broke and is causing some problem?  I've looked at parts lists online and don't see anything that shows the bolt or anything that might set inside of it.
Thanks for your help

Answer
Check out this link:

http://www.smallenginesuppliers.com/html/engine-specs/tecumseh/Tecumseh_Cast-Iro

I would start by cleaning the carburetor with compressed air from an air compressor and carburetor cleaner.  You will need to remove and dis-assemble the carb to clean it.  Pay attention to the carb connecting link...mark the linkage and take a digital picture before removing so you know how to re-connect the linkage.

With the carb cleaned, replace the inlet needle and seat along with the float.  Tecumseh brass floats are prone to leaking.

With the carb clean and the inlet needle/seat replaced the engine should run great.

I have seen the plastic restrictor you mentioned but if the parts lists does not show a replacement part I would run it with out the restrictor.

Let me know how it goes.

Eric