HELP 2002 Ranger 500

[dtaylortx]

I just bought a 2005 ranger 500 that has been sitting at my friends for a year. I replaced the battery, checked the fluids, drained the gas and refilled it, removed the old gas from the lines and fuel pump.
It would not start, it would crank but not fire. I removed the air filter and sprayed starter fluid in it. It ran for about 10 seconds and died. It would not run on fuel.
I removed the carb and got a rebuild kit. It was green and gummy inside.
I also bought another cheap amazon carb just incase.
I went back, put the carb on and it started and ran for about 30 seconds. It then looked like the fuel pump had stopped working and it cut out.
I could not get it to restart.
I disconnected the pump and tried to get the pump to run directly from a gas can onto the ground. It would vibrate and make the usual noises but no fuel output.
I put another fuel pump on it and it would still not run.
I blew into the fuel line from the pump to the carb and i was blocked. (I figured the float was up and the needle had closed off the fuel.)
I took the carb off and it was full of fuel.
I put the amazon carb on and tried, fuel drained from the bottom of the carb (I know, what did I expect).
I have a couple of questions.
1. Is there a sensor that restricts the fuel, (I'm wondering if the original pump was good, now I know the bowl was full).
2. Why will this now not run when it was running good for 30 seconds, it sounded great.

advice is appreciated, I'm kind of stuck now, the bike is 30 miles from me so its a nightmare traveling back and forth with tools. I wanted to get it back to my place but the brakes are also seized.

[klm]

Good write-up — you already did a lot of the right things. A 2005 Polaris Ranger 500 is pretty simple fuel-wise, so the good news is there aren’t many mysterious sensors that “shut fuel off”. This problem is almost always mechanical: fuel delivery, vacuum, carb, or spark.

Let’s answer your two questions directly, then I’ll give you a short attack plan.

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1) Is there a sensor that restricts fuel flow?

No.
On a 2005 Ranger 500:

There is no electronic fuel control, no ECU, and no sensor that shuts fuel off.

Fuel flow is controlled by only:

• Fuel pump (vacuum-operated)
• Fuel lines
• Carb float & needle
• Tank venting
• Petcock / fuel valve (if equipped)

If the float bowl was full, the pump was doing its job. The engine dies because fuel is not getting from the bowl into the engine through the jets, not because something "turned the fuel off."

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2) Why won’t it run now when it ran for 30 seconds?

This is classic carb-clog behavior.

It ran on:

• Cleaner fluid
• Fuel already in the bowl
• Whatever fuel partially flowed before debris moved

Then it died because:

Most likely causes (ranked in probability):

A) Pilot jet or main jet is plugged (MOST COMMON)

When varnish breaks loose, it moves downstream and immediately blocks tiny jet openings.

Symptoms:
• Runs briefly then dies
• Won’t restart
• Bowl has fuel but engine acts starved
• Starter fluid allows momentary run

✅ Fix:
Pull carb again and:

• Remove pilot jet
• Remove main jet
• Remove emulsion tube
• Spray carb cleaner through everything
• Blow with compressed air (not optional)
• Pass thin wire through jets if needed

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Tank vent is clogged → vacuum in tank

If the tank cannot breathe, fuel flow stops after a short run.

✅ Test:
Remove gas cap and try to start it.
If it runs, vent is plugged.

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C) Vacuum line leaking to fuel pump

If the vacuum line is cracked, loose, or plugged, the fuel pump will stop after initial fuel.

✅ Test:
Pull vacuum line off pump and crank engine.
You should feel strong pulsing suction.

No vacuum = hose issue or intake leak.

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D) Amazon carb quality issue

Low-price carbs often have:

• Wrong float height
• Faulty needle
• Leaky bowl
• Wrong jet size
• Improper gaskets

Fuel leaking out the bottom = float/needle defective.

✅ Use the OEM carb you rebuilt after cleaning it again.

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E) Spark failure after warm-up

Much less common, but possible with an aging ignition coil or stator.

✅ Test:
Pull spark plug and check immediately after it dies.
Spark should be bright blue.

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A very likely scenario in your case:

It ran well → debris moved → jet plugged → bowl stayed full → engine starved → now dead.

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What I recommend you do next (simple order):

Step 1:

Remove gas cap and try to start it (rule out tank vent)

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Step 2:

Pull your ORIGINAL carb back off and:

• Remove pilot + main jets
• Spray + air blast them thoroughly
• Make sure spray shoots cleanly out of idle port
• Reassemble

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Step 3:

Check vacuum line to fuel pump:
Crank with line removed → must feel suction.

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Step 4:

Ignore the Amazon carb for now.
Use your rebuilt OEM carb only.

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Step 5:

Verify spark after it dies.

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