Lawn Mower Primer Bulb

Hi Everyone, 
I have a question about my MTD lawn mower primer bulb. It leaks when i push it so its done. I can squeeze just enough gas through it to get the mower to start for a few seconds, then it dies. Am i correct in thinking that since the primer is broken, the mower loses fuel vacumn to keep it running? Also, the primer bulb is the larger round red type with a black housing and has "PRIMER 2.0" printed on it. The part number is 951-05177A for reference. This primer appears to be an upgrade from the 951-05177, with just "PRIMER" printed on it. So this was the main reason I posted, are the 2 different primers that I listed interchangeable or are they potentially different? The 2.0 version is difficult to source. Thanks