How do I know if the fuel I used has water in it?

Without knowing the year of the vehicle, I must assume that it is an older, high-mileage vehicle. Things to check:

1. Tune-up (if the vehicle has not had one in the last 5 years or 25,000 miles);
2. Check air filter;
3. Replace fuel filter;
4. Fuel may be contaminated. Replace all fuel in vehicle;
5. If the problem persists, check for clogged fuel pickup strainer, proper operation of the fuel pump, and proper operation of the fuel pressure regulator.
6. Avoid fuels with high ethanol content, and use a fuel system water remover additive when you must use ethanol fuel blends.

water in fuel,drain the water out of the fuel filter by releasing it through the valve on the bottom of your fuel filter. unscrew the valve on the bottom of primary fuel filter,you have 2 fuel filters. one is primary,one is secondary. you did'nt specify what engine,or what year, but will try to assist you anyway. drain the water out of the primary fuel filter by draining the water out of the primary fuel filter,you will see a pep **** valve under the fuel filter,turn it counterclockwise until you see the fuel coming out, after you drain that fuel filter drain the 2nd one. this will solve your fuel issues for now.but i do suggest you replace those 2 filters. you can prime the filters with transmission fluid in order to restart the engine. i have u.s.m.c. training in heavy equipment,ooooraaahhh.if you know this,,, you'll know #1 we never leave a man behind.wish you the best. thank you for choosing fixya.com

The indicator you see is call a water in fuel warning lamp. ==== This a very important warning and you will need to take corrective action ASAP. ==== As a diesel owner,you need to know diesel fuel can attract moisture. When condensation (water droplets) collect inside the fuel tank,it will contaminate the diesel. ==== The corrective action is to locate the drain **** on the fuel filter and CAREFULLY drain the water from the bottom of the filter housing. (with engine off / key out) ==== The water in fuel warning light will go off as soon as the water is drained. ==== Use one bottle of RED Iso-Heet to remove any additional water inside the fuel tank.

Your engine should be the 6.0, where did you drain water from? The place to drain water is the fuel pump on the rail. The only way to get the water out is to remove the allen-head screw that you will see halfway down the electric fuel-pump, on the bottom-side. Let me know if that is what you see and how it went. Also if we are are talking about the same fuel system your fuel filter kit should include two fuel cartridge filters.

The only fuel filter is in the fuel/water heater/sperator. If it is dying, the glow plug circuit should be checked first. The glow plug light should illuminate for around 10 seconds. The next thing I would check would be the fuel pressure going to the fuel/water seperator. Let me know what you find and if you need diagrams let me know.

There are special electronic fuel pumps you can get for this kind of conversion that wont put to much fuel pressure in the carb and blow the bowls.
As long as the distributer is vacuum advance and for a 302 it should be able to work. The main difference will be the firing order on the truck engine may be different. So you have to make sure your #1 cylinder is at top dead center and route the post on the cap its pointing at to the #1 cylinder and go from there.
The intake and carb you have should also work.

Exploded view of the thermostat arrangement—3.8L engines

Sounds like you may have gotten a bad tank of fuel. I don't know where you live but sometimes if the weather has been real rainy water will seep into the in ground tanks and then pumped into your tank. Disconnect the fuel line at the engine and pump out some gas into a clear jar. Let is seat for a few seconds. The gas will separate from the water and be on top. To fix this problem will require draining the tank and adding new fuel. There are products used to absorb water and make it mix with the gas so it can be burned off. On boats they use a water separator fuel filter just for this condition.

Check the throttle... If i am not mistaken it could be an electronic instead of cable operated. Check pedal rheostat and possible throttle motor.

Water in fuel
During refueling, it is possible for
water-contaminated diesel fuel to be
pumped into your tank. Your vehicle
fuel system is equipped with a fuel
filter/water separator to remove water from the fuel. The WATER IN
FUEL light will illuminate when the ignition is turned to START (as part
of the light function check) and when the FCM/HFCM has a significant
quantity of water in it.
If the light illuminates when the engine is running, stop the vehicle as
soon as safely possible, shut off the engine, then drain the FCM/HFCM.
Refer to Draining the FCM/HFCM and changing the fuel filters in the
Maintenance and Specifications section of this supplement for the
drain procedure. Allowing water to stay in the system could result in
extensive damage to, or failure of, the fuel injection system