Where is the pilot light for the efel model 491.64 propane vented room heater? I would appreciate some clear direction, if possible.

It sounds to me that you purchased a natural gas version and just connected a regulator to it thinking that would work? Yes?

To do the conversion from Natural Gas to Propane or vice versa, you need a new set of jets as well because the sizes or the holes is different. Having said that, it appears they do 'Duel Fuel' models, make sure you have one.

Return it and get one designed for Propane. It will come with the regulator attached and set.

https://www.mrheater.com/product/heaters/vent-free.html

Contact them direct as it is still a warranty issue.

verify the inlet pressure to the heater. those pezioelectric spark lighters are garbage. make sure all manual shut off valves to the heater are open. Pilot tubing may also be blocked

if it is direct vent chances are it has electronic pilot.. it does not have a standing pilo and match size upt. if in fact it did have a buning pilot there is a part called thermocoupling. it will look like a 1/8 in. copper wire coming out of the bottom of the gas valve and goes right to the pilot. anywhere from 10 in. to 20in.. unscreew nut at gas valve pull out from pilot area [ it just clips in at pilot] take it to any home center

Open following links for pilot light help:
http://waterheatertimer.org/How-to-install-gas-water-heater.html#troubleshoot
http://waterheatertimer.org/pdf/Pilot-light-will-not-stay-lit.pdf
http://waterheatertimer.org/images/Negative-pressure.jpg
http://waterheatertimer.org/pdf/Bosch_Ventilating_tight_houses.pdf

Since pilot light goes out and can be re-lit, problem is probably not thermocouple, gas control valve, or air in gas line. But these things can factor in as contributing factors.
Problem is likely one of following or combination of following including dirty burner parts, tight house, incorrect vent lengths, negative pressure caused by other venting appliances, condensation dripping down into combustion area, and inadequate oxygen supply due to hot or closed-off room or attic location.

Gas water heaters draw air from surrounding area. If water heater is located inside house, then air has to enter home through cracks and when doors and windows are opened. Other gas appliances and vent fans also draw air from same indoor area. When other vent fans turn on, air can be drawn down the water heater vent and blow out pilot light.
Inspect combustion chamber to make sure there is no condensate water dripping down from incorrect vent that is putting out flame. If combustion chamber is dry, then close doors and windows. Turn on all vent fans and gas appliances that vent outdoors, and see if water heater pilot goes out.
Consult with plumber or product manual about proper horizontal and vertical lengths of vent pipe for your model. Have plumber clean combustion parts and inspect vent termination and check gas pressure and bleed gas line.
Add louver opening to outdoors so air can enter room where water heater is located.

Replace the thermocoupler?

need more propane?

ODS DEMO

If you need further help, reach me via phone at https://www.6ya.com/expert/dan_73bbd84fe1d95b61

sounds like an obstruction in pilot assembly.try using canned compressed air to blow directly into pilot. this technique is successful about 70%. if not,pilot assembly must be removed and cleaned thorougly

I've seen excessive draft draw the pilot flame away from the thermo couple when the burners light so when the burners shut down so does the pilot.

You have a crack in your heat exchanger and it is sucking in products of combustion. Replace the heater. OR there is a blockage in the intake or exhaust vent. GET IT FIXED OR REPLACED!