My lawnmower engine turns over, starts (tells me it's getting gas and firing) and then instantly dies out. I can immediately start it again and again and again with the same result. I can't figure out if it's an electrical or fuel problem. If it has enough gas to start right back up, why does it immediately shut off? I think I've ruled out the seat safety switch by jumping it out and the oil pressure switch by unplugging it.

Being a V-Twin, access to the carburetor bowl and fuel shutoff (anti backfire) solenoid is blocked. I'll have to remove the carb to get to them so before I do all that, I thought I'd reach out for some help.

Make: John Deere
Model: GT235

Engine: Briggs & Stratton Vanguard 18HP V-Twin
Model: 350777
Type: 1154-E1
Code: 00052211

Sounds like fuel starvation. Fuel filter?

If it was electrical I'd expect it to run until something warmed up, then quit and not run again until whatever that was cooled back off?

Have you been running ethanol gas?

I would say some dirt or water in the carburetor.
Does it have a fuel drain from the float bowl somewhere? Drain that, see what comes out and start again.
Also may have a fuel solenoid so check that too.

Sounds to me like a fuel starvation issue. Basically flow to the carb cannot keep up with the consumption from the engine. The shutoff solenoid or the float bowl needle and seat would be my likely culprits.

If you don't want to tear covers off and get elbow deep in the carb, I would first disconnect the fuel line and make sure that there is good flow to the carb. If so, then get after needle and seat / solenoid.

Sounds like it's being starved for fuel. Go all the way through the line and check the filter. It may also be the carburetor. They're usually not to complicated to rebuild.

Clean the carb

The fuel filter was replaced last season. I did remove the fuel line going to the carb and placed it in a clear plastic bottle, turned the engine over and the fuel pump is pumping gas into the bottle.

Check your oil level. A lot of engines have a low oil level/low oil pressure sensor. If you have normal oil quantity the sensor might be bad.
Good luck

Make sure gas cap vents also.

Check the air filter as well as the stuff already mentioned.

Water in the gas? Has it sat all winter with the tank half full? I have the best results with storing mine with the tank completely empty.

Yes, I do run ethanol gas...the gas that's in it now was purchased 0n 12-28-19.

As mentioned - fuel starvation.

A little dirt in the fuel to the carb float/needle valve - restricted fuel so it refills slowly, allows enough to start then runs out of gas and it stops. While you’re fiddling around a little more flows in, repeat...

Might be from water/alcohol corrosion in the carb from some fuel sitting over the winter. When I remember to do it, I will shut off fuel to the carb after the last mowing in the winter. Let the engine run until it runs out of gas. This empties the carb for the winter.

Looks like I'm going to have to tear it apart and see what's going on. I think the Reverend has hit the nail on the head.

It's fuel 100%. The reason it's starting and dying is the float bowl is getting drained and not refilling fast enough. Make sure you have clean gas, tank, filter and lines and then if that still doesn't do it, the carb needs a quick rebuild. Kits are pretty cheap for most mower engines. Disassemble, soak everything with carb cleaner, blow it all out well and re-assemble with fresh gaskets. Could be clogged needle valves, stuck floats or a combination that why it's best too just do a strip down and total rebuild.

The carbs on these are a piece of junk. I had a GX 345, about the same thing but liquid cooled. Fortunately, it was stolen last fall. I put one $350+ carb on it, still had running problems and lack of power, and I WILL NOT use ethanol gas. That carb is a true pain in the butt to get to. The hood pulls of to the front, unplug the lights first. Then take off the heat shield, and you may be able to get the float bowl off. Be very gentle, this stuff is quite fragile. Leave the float alone, as the hinge pin is pressed in. Spray it good with carb cleaner, carefully put it back together and hope for the best. Good luck.

I agree with the others - given the information so far I'd guess that the carb is dirty and it's starving for fuel.


You might want to try running some Seafoam through it before you tear it apart. I've had reasonable success with that in the past if it wasn't clogged up too bad. I believe Seafoam has a pretty high level of naptha (a cleaning agent).


I've switched to running non-ethanol gas as well and have much better luck with my small engines since.

quote:

Originally posted by P229 357SIG Man:
Yes, I do run ethanol gas...the gas that's in it now was purchased 0n 12-28-19.

Did the ethanol gas sit in the lawnmower over winter?

quote:

Originally posted by ShouldBFishin:
I've switched to running non-ethanol gas as well and have much better luck with my small engines since.

^^^^ THIS!!!!