Skip to main content

Repair guides and support for a wide range of small engines.

76 Questions View all

No fuel to spark plug Briggs & Stratton #12T402-2136-F8

Ok. I’ve cleaned the carb (extensively), even put on a new one. Changed the oil, cleaned the fuel lines (all), new air filter, new spark plug, cleaned the gas tank, new fuel, everything I can think of. All gaskets are present. There is no fuel filter on this model. Throttle and choke checked. No gas leaks, no oil leaks. Any ideas? (Same thing is happening on my TROY built weedwacker also-weird).

Pls help!

Nicky

Answer this question I have this problem too

Is this a good question?

Score 0

Comments:

@onlyonenicky do you have gas in the fuel bowl on the bottom of the carburetor? Does your engine start if you pour a little fuel into the carb?

by

Yes, there is fuel in the carb bowl. Everything is good until I try to start it and then no fuel gets to the spark plug.

by

Nope. Not even when I try carb cleaner

by

@onlyonenicky okay so you have more than a fuel issue. You also have a spark issue. When you pull the spark plug out and ground it against the engine block, then try to start your engine, do you see a spark (can't do it in a bright light)?

by

Carburetors may form deposits blocking fuel flow as a result of ethanol in gasoline. This may require removing and disassembling the carburetor to clean and remove hardened buildup from ethanol absorbing moisture. Ethanol will attack rubber and seals while moisture may corrode aluminum and brass parts. The best way to check for a working carb is removing the spark plug after several failed starts - the plug should be wet and smell of fuel.

If spark isn't seen as suggested with a spark test then the ignition system may be faulty. As I understand B&S engines, magneto ignition uses a flywheel with magnets generating voltage from a magnetic pickup that's converted to high voltage for spark.

by

Show 4 more comments

Add a comment

1 Answer

Most Helpful Answer

I've always found the easiest way to determine a spark/fuel issue is to remove the sparkplug, pour a few drops of good gas directly into the sparkplug hole (this can be a little difficult if the sparkplug is oriented horizontally - you can find a way, though), replace the sparkplug and try to start it. (Careful with the gasoline. I don't want to be responsible for you blowing yourself up!) If it fires and runs for a few seconds, you know you have spark and your issue is with fuel (or air). You said you have a new carb and fuel lines. There may be an air leak in the intake manifold; check all the screws/bolts to make sure they are tight. If they are loose, tighten them sequentially (even if there are only two) a little at a time. Don't overtighten them - you don't want to break one off!

If it won't fire over with fuel poured directly into the spark plug hole, then you may need a new magneto. They can fail suddenly. Pretty easy to find online, usually not too expensive, and a fairly easy install if you have basic tools (which sounds like you do). There's also a lot more detailed diagnostic info for deciding if it's the magneto online, too.

Personally, I would never use fuel containing ethanol in one of these engines. Luckily, I live in a State where uncontaminated gasoline is still available.

Was this answer helpful?

Score 1
Add a comment

Add your answer

Onlyonenicky will be eternally grateful.
View Statistics:

Past 24 Hours: 0

Past 7 Days: 6

Past 30 Days: 23

All Time: 93