Small Engines (Lawn Mowers, etc.): tecumseh OVRM120, tecumseh carburetor

Question
My dad gave me a Scott's rear drive push mower with htis engine. He had it for about 5 years and it sat for four of those. He did not use a fuel stabilizer and it had about a 1/4 tank of fuel. I tried to start it but it didn't work (obviously). I pulled the carb and cleaned the whole thing with carb cleaner. I made sure all orifices were clear before reassembling. I replaced the spark plug and air cleaner. I put new gas in it and it still doesn't want to run. It'll run for a few seconds on carb cleaner. A friend of mine suggested the primer bulb might be leaking. When I press the primer, it doesn't get stiff like a primer bulb usually does. If it might be the primer bulb, are they easy to replace?? I looked and couldn't figure out how to pull the old one off. If I should be looking at something else, please let me know. I plan on working on this tomorrow and hopefully get it running. I have someone who wants to by my Toro push mower and right now, it's the only thing I have running.

Thanks for your advice in advance.
Scott

Answer
Personally, after sitting for four years with gas in it, I wouldn't even bother trying to rebuild the carb, I'd replace it.  After sitting for that long, the odds of getting it clean aren't good.  If there's any sign of corrosion, I'd immediately scrap it and buy a new one.  The primer is probably bad after that long.  They're easy to replace, it should be held in with a metal ring that you pry out, but that's not causing your problem.  

You can keep trying to clean it and you may get it to work.  If you do want to try that, you're probably going to need to soak it for a few hours, or longer, in carb cleaner.  You can buy a soak can at any auto parts store, but by that time, you're probably pretty close to what a new carb would have cost.

Let me know if you have any questions.  Thanks, PK.