Deere S240 no start, fuel problem?

dwatson57 · Mar 9, 2019

I recently bought an S240 with less than 3 hours, but has been sitting for 2 years. I charged battery and it cranks engine, but no start.

Here's what I've done so far:
Removed air cleaner and if I dribble fuel in intake side of carb, the engine will start and run.

Removed fuel line going to carb and cranked engine. After a bit, fuel runs out so I assume fuel is getting to carb.

Removed the fuel shutoff valve from bottom of carb and reconnected. I can see the needle retract when key is turned on.

I suspect that ethanol fuel and sitting for 2 years may have caused carb to be plugged up or something.

Is there something else I should be looking at?
Are these carbs fairly easy to disassemble & clean?

Thanks for your help!

tomplum · Mar 9, 2019

Welcome to TBN! The carb could very well be messy and in need of cleaning. You could try removing the bowl and cleaning the main which is in the center stem. A few bursts through the straw on your spray carb cleaner may do the job. Of course the fuel supply has to be fresh so drain and refill. The carbs are not a lot to them and should you feel it should come off, you lock two of the carb nuts together and extract the mounting studs. Just take care getting the linkage /spring back on as it came off. The main comes out in two parts, just be care to use a good sized screwdriver bit so you don';t spin out the slot. A pic as it comes apart could be good for reference. Keep us in the loop.

dwatson57 · Mar 14, 2019

Problem solved! Finally!

Took carb apart twice and cleaned with spray carb cleaner and compressed air. Still no go. No combustion unless I dribble gas in the air intake.
Local Deere service manager thought I probably missed cleaning something in carb and suggested ultrasonic cleaner at Harbor Freight using 50/50 mix of simple green & water. I did that twice and still same result. Each time I removed carb, the bowl would be full.

The only way engine would run a bit was to entirely block intake and it would suck enough fuel to run, then I could keep it running by exposing only the slightest sliver of the air intake.

Verified that when fuel line disconnected from carb and engine cranked some fuel would come out. It was small amount, but enough to run the engine. With fuel line connected to carb, disconnected it from fuel pump and used old enema bottle with the long snout for a tip and filled it with gas and stuck it into fuel line and applied slight pressure. Engine actually ran on its own for a bit. Fuel was squirting out the fuel pump, so I stuck my finger over it. That stopped pump output with no noticeable pressure against my finger. Connected a spare fuel line from pump to catch can and used enema bottle and ran engine several minutes. Flow from pump increased some and had more pressure.

Then connected fuel line back from pump to carb and engine ran fine.

Moral of story. . . Some fuel coming out of pulse fuel pump may not be enough. My theory is that diaphragm in pump wasn't sealing against back pressure--maybe is was dry & stiff. After running for a few minutes it limbered up and pumped well.

Maybe someone else has a better understanding to explain why it started working??