I had a 5 HP craftsman lawnmower drive me nuts no start cold. I had the carb and tank spotless good fuel flow out needle and seat. I took air filter off would start with one squirt of starter fluid every time then restart hot AOK. Looking in the air inlet with air filter off no gas squirts out main center jet when I hit the hour shaped primer. So primer is not priming -dah. I took a sharp ice pick and gently pried the locking tabs on the retainer ring out 1 at a time so retainer ring slides up out of hole when you gently pull up on bulb not to ruin the rubber. You do not need to ruin the bulb by pulling hard on ring to get it loose. Put ice pick point between the 5-6 lock tabs end edges to move tab .010 inch. Now that bulb is out I could see old dirt on inside of bulb seating area so must not be tight seal. Cleaned the bulb and bore of carb housing real good then put silicon sealer small amount on bulb and installed same bulb with 3/4 socket to push original retaining ring back down and bend tabs flat again. Then sealed outside OD of bulb with silicon to let dry. Next day would squirt fuel with every push of the hour glass shaped bulb. May work on other primer bulbs too to reseal and fix.Now mower starts with 5 pushes stone cold everytime so I can sell it. Cost to fix -zero parts just a little sealer. Good for me.:thumbsup:

Hate to burst your bubble,but gasoline will disolve silicone.It's probably already done so.Sorry

If the carburetor is not flooding, then fuel should never make it up to the primer bulb, only air.

ya, you will more than likely be regretting doing that, cause if you tip the motor on its side, some gas may get into the bulb, and your silicone will be gone, and plug up your carb

best thing to do is to make sure it is completly clean, than put the bulb back on

one thing I've always hated about tecumsehs are thier priming system on thier push mowers

I hate to put any goo on anything I might need to take apart again, however if I dont plan on taking it apart I use a thin bead of Permatex 2 black make a gasket, it resists gas and oil, I think you use alcohol or acetone to remove it. Have a good one. Geo

I personally have never put sealer on the primer, but I can't see any reason that it would not work. If you tip the mower and the seal is not good enough to keep the fuel out, then it's not sealed.

If you fix the primer right on a Tecumseh carburetor.... Then there is nothing to hate...