I experienced a crash with my Brodak 40 powered Brodak P40, cleaned the engine and realized that the needle valve was bent. I straightened the needle valve and got the engine to start. After 2 flights, the engine wont run for more than 10 seconds. While attempting to restart the engine, I noticed debris in the fuel line so I decided to scrap the tank which is a Deep Wedge Profile Standard Vent Fuel Tank 4 oz., only to find it extremely rusty. I cleaned the tank, resealed it and checked for leaks and attempted to run the engine again and it still would not run for more than 10 seconds. Can someone assist? At this point I cannot tell if it is the tank, nva or something inside the engine.

  Describe the crash in more detail. How did it hit. There are crashes and then there are crashes!   I crashed a profile model straight into asphalt once, Destroyed the airplane, but on impact, the plastic spinner took some energy, and then the mounting bolts sheared, then the engine slid back in the mounts so that the maple motor mounts took the brunt of the impact. The muffler broke in half and that was about it. I got the engine home, cleaned it off oil it up, and that engine was run hundreds of times since then and is still in good operating condition. On the flip side of this coin, I had a model that crashed at a slight angle inverted during an outside maneuver.. The cylinder was up right and didn't even break the plug. The model hit at about a 30 degree angle, broke the nose off and a wing came off. All repairable. I got the engine off, cleaned it it and put a new prop on to see if it would turn over, made one easy revolution and then it stopped. Back plate off to check an the rod was coming off the crank pin. Pushed it back on, gave it one more revolution and watched it work off again. I held the engine up to look at it from the side and held another one up next to it to compare it, and then I could see that the crank shaft was not perpendicular to the cylinder any more. There was no other damage to the engine, didn't even break the stock muffler. But the crank case was wildly distorted, No cracks or anything visible. I pulled the engine completely apart, and still no visible damage, but the engine was ruined! I think the only thing I was able to reuse was the back plate, head, prop drive washer, and believe it or not, the crank was OK. But everything else was distorted and useless.
    You probably have something similar going on. From what you have provided, the first thing to try is a whole new needle valve assembly, as long as the engine turns over and flips through normally. If it still doesn't run, look for cracks in unusual places like under the mounts where they meet the case and such. The B-40 case is pretty light and thin, not too much unlike a Fox .35 case so slight damage that is hard to see can let it suck air and not run beyond a prime, if it will prime itself at all. If you have to put a prime into the venturi to get it to burp, that is a sign it's sucking air some where. A magnifying glass and a good light will let you look over the entire engine case to see if there are any cracks.
  Type at you later,
   Dan McEntee

I make my own needles. Just find the correct socket head machine screw in your hardware drawer, chuck it and take a file to it while spinning.

Nice thing here is you can use a ball driver to adjust.

I've never seen an easily available SHCS that matched any needle stem I've ever used. Where do you get a 4-56 or a 3-128?

  I think the Fox is 3-48.

    Brett