OT -- Briggs & Stratton Carb Question
Neighbor's riding Lawnmower with a B&S engine. The engine would try to start but would die in a couple seconds. Sounded like a fuel problem so the tank was drained and installed a new fuel filter. That didn't help. Ended up pulling off the solenoid-looking thing from under the float bowl. The plunger was stuck in the down position -- we loosened it up and now the engine seems to run. What does this solenoid-looking thing do? Thanks in advance.
When the key is on, the solenoid pulls the plunger down. This allows fuel to flow through the main jet. When the key is turned off, the plunger moves back against the main jet.
This was done to stop the backfire you sometimes get when shutting these engines down, hence the name.
Fairly common problem. If it gives you any more trouble, just cut the end off the plunger. A new one cost about $60.
It sounds like there is garbage stuck in the main and idle jet passages. Get a can of good carb cleaner, unscrew the main jet, emulsion tube that is below it, and the idle mix screw. Spray the passages librally and the jets and emulsion tube. It only takes on or two plugges holes in the emulsion tube to cause a whole host of problems.
Blow everything out with air and reassemble. 1 1/2 turns out from lightly seated on the main and idle screw will get you running. Most of the problem is with the new gas that has alcohol in it and goes stale in short order...and forms a sludge just as fast.
Mr. Chamber, the anti backfire solenoid was stuck, he fixed it. That type does not have a high speed needle, it uses a fixed orifice.