Older LawnBoy - Hard Starting

Hi forums,
I'm Mark and I just signed up after doing some research online.
As for my user name, I belong to several different forums covering many different interest areas and I use the same "user name" for all.
I have an older LawnBoy (I'm not sure of the model) and it is hard to start.
My father bought it brand new in the late '70s or early 80's but the mower is in pretty good shape, this is the first real issue..

The mower has a new plug and lots of spark, however the muffler is getting bad.
After a few primes and pulls is will begin to run rough. If I pump the prime a few more times, it will start to run then die off again, so I prime it again and it will run.

I'm thinking that the initial prime from a cold start is not drawing enough fuel to the allow the mower to fire and run as it should.

I read some info online but I'm not really sure of what direction I need to go in to fix the situation.
Any idea, info or tips would be appreciated.

Thanks in advanced,
Mark

You are not getting a steady fuel supply so check for a dirty filter. In the carburetor you might have a metal screen over the main jet.

In cleaning the carb, you have to remove the metal screen over the main jet, unscrew the jet from the carb and clean with spray cleaner and a wire thru all the jet holes to really get it working properly. Other reasons for hard starting are low compression, bad reed valves and leaky crankshaft seals.

and if none of the above works? try replacing your crankshaft seals..if its a two-stroke,wich considering its age im thinking it is.