Small Engines (Lawn Mowers, etc.): B&S engine wont start

Question

Carburetor  

Engine   B&S 92502 3186 01 Magnetron. Lawnmower. The mower was in the cellar for the winter. When I first took it outside it wouldn't start until I pulled the plug and put an eyedropper of gasoline in. Put the plug back in and the mower started and ran about 15 minutes, until it ran out of gas. This was gas left from last fall.

I refilled it, and from that point on, it will not start. If I put a bit of gasoline in the plug hole, it will start, but only runs a few seconds then stops.

I made sure the gas tank was empty and dry, then filled it about half way with fresh gasoling I just bought. Same thing. Only starts when I put a little has in the plug hole and runs a few seconds.

If this is caused by the old gas that sat in the engine all winter, why would it have run for 15 minutes until it ran out of gas, but won't run now? Does the carburetor need cleaning, or would adding a gas stablizer now clean it? If not, is there anything that would clean it just by adding something to the gas?

Answer
Most likely you will need to replace the carburetor diaphragm.

You have a Briggs and Stratton pulsa-jet carburetor.

Here is a You Tube video:

https://www.youtube.com/watch?v=fdFrniPyBwE

Those carburetors tend to warp but you can level them again with a flat file but you have to remove the fuel pick-up tubes to file the bottom of the carb.

Eric