Water Heaters - Burner blows out pilot

Pilot on trailer 5gal W.H. is OK and Thermocouple works fine but when heater fires up to heat water, propane "explodes", blowing out pilot. Cure?
Thanks guys.

How old is this unit, and has it been inspected to make sure it has proper ventilation/code approved location?

Unit is about 5yrs old and used daily. It was installed as a replacement, out with the old and in with the new, and has worked very well up to about 3-4 days ago. Had a heavy wind/rain storm which blew out the pilot. I relit it when weather calmed then the problem came up. Took it apart today, cleaned pilot orfice and guide, have a nice flame which hits TC correctly. All seems tight and secure. Seems that the pilot will not ignite the burner until buildup of gas is high, touches if off, "explodes" with enough force to blow out the pilot. Do I need more pilot pressure?

First I want to thank you for your timely reply....
After a thorough cleaning I put the Pilot, Thermocouple and the burner tube back together and managed to aim the pilot correctly to the TC while "cheating" the burner tube about 1/8th inch more toward the pilot lite allowing the gas to flow more into the pilot flame. A very light twist accomplished this and away we go. All works like new again. Amazed how a little can be so much....Thanks again.