It should have a remote primer attached to the blower housing. in most cases it is held in place by three head bolts at the top and two bolts on the bottom of the sides. Remove it taking care since the hose from it to the carb is there also. The hose is worked loose and then there is probably a nut holding it in place.
A cracked primer bulb. You will need to replace it.
primer bulb replacement on craftsman 32 cc week wacker
You don't. They are not difficult to replace.
You have the letters out of order. HMSK100 for horizontal medium-frame Snow King for a snow thrower engine for dual stage machines. Look to the link at the bottom for a manual; generally destroy the keeper, remove the old bulb and use a socket to drive in the new keeper (and bulb.)
Don't know that a leaking primer bulb can be repaired. Most likely, you have to replace it. You don't want to forget the routing of the fuel lines!! You might want to make a drawing of the routing before you remove the primer bulb.
Remove the filter cover. unhook the two fuel lines behind the primer bulb. Remove the two screws (inset star) that hold the carburetor, then gently rotate the filter base to expose the back of the primer bulb push the two retaining tabs and remove the primer taking notice which fuel lines go into it, one is longer than the other. Replace in reverse order and replace gaskets if damaged. Paul
A detailed description is available in related links.
Check with Ebay, I found one there.
No gasoline is reaching the primer bulb.
You either have a bad bulb or a bad fuel line between the bulb base and the gas tank. If there is the slightest hole or crack in the bulb it will not work. They are easy to replace.
www.odref.com/poulan/pdf/snapper/all/s31sst.pdf
There does not appear to be a primer bulb on the Stihl BR400 that I can see in the exploded parts.