Portable generator won't start

Question

Cliched story, I know: I didn't use the generator (4 Stroke Briggs & Stratton) for a long time, and when I tried it, it wouldn't start.

I'd pumped the gas out of the tank after I last used it, but I probably made the mistake of not running it to empty, so I figured that would be the problem.

Not that I really knew what I was doing, but I took apart the carb (not a full disassembly: just taking the cover off the bottom) and dumped out the gas that was there, and opened the shutoff to flush the remaining gas out. Closed it up, added gas and turned on the shutoff, and it caught and ran... for a second.

Tried this again (opening, flushing) a bunch of times more, but IIRC it maybe sputtered to life briefly once more.

I changed the spark plug. I also opened the air filter cover, opened the choke, and sprayed with carb cleaner. Closed the choke,started it up... and it ran for a second or two before sputtering out.

Each time I sprayed carb fluid in it would run for a second or two. If I acted quickly and sprayed more fluid in right after pulling the starter, it would keep running, though I didn't keep going this way for any extended period.

From this, I presumed it meant gas wasn't reaching the carburetor. I took the fuel line off where it met the carb, put the line into a gas can, and opened the shutoff, and fuel ran.

So gas is presumably reaching the carburetor from the tank. And if I'm able to sort-of run the generator (for a short time) by spraying carb cleaner into the air intake, something is reaching the cylinder.

But I'm stumped. Could it be that I'm consistently putting the carburetor together incorrectly? The only real loose part that had to be put back in place was a small spring.

Answer 1

As gasoline evaporates it leaves a gummy varnish in the carburetor

Gasoline sitting for three years in the float bowl of a carburetor will surely lead to some varnish. The hydrocarbons evaporate from the fuel and oxygen acts as an oxidation catalyst changing the remaining components into other compounds leaving varnish in their wake.

Varnish will coat and clog the inside of the carburetor. Float bowl, floats, needle and seat as well as any jets the were submerged in the gas.

Clean the inside of the carburetor

I would suggest at the very least you remove the carburetor and take the float bowl off. Get some carb cleaner with the little red straw/hose that you can use to spray into jets and and orifices of the carburetor. Let it sit, do it again and use a bowl to capture the runoff. You can let the carb sit in the bowl for a bit if there are trouble spots. Use a toothbrush. Get a thin piece of copper wire you can stick into any jets to ensure they are not clogged. Those are your real trouble areas. Take your time. Be thorough or you will have to do it again.

If you have some extra carb cleaner you can spray it around inside your fuel tank to clean that out a bit too. Spending a little time on the gas tank will pay dividends.

Replace your fuel filter. They are cheap.

If the engine runs with starter fluid, that means you have compression and spark. The last piece is fuel delivery. Focus on that and you will be victorious.

Best of luck.

Answer 2

Stale crystallized fuel could be clogging the ports of the carburetor. The easiest way to remove the blockage is to soak the carb in a cleaning solution made for metal engine parts. You must remove all plastic pieces from the carb before soaking. I've used this cleaner before with excellent success.

Even though there is fuel at the carbs' intake if the gas caps vent is blocked no amount of suction will move the fuel through the lines. Check by loosening the cap and try starting.