I had issues getting my Sceadu started a few times as well. I found the biggest culprit was the glow plug contact clip on my remote glow lead. This has only been a problem with the Enya #3 and I'm not sure why. I have found if I dont get an instant start all I have to do is reach under the cowling and press the boot/clip down on the glow plug center stud and it lights instanly on the next start attempt. I have the same remote on two other helis with no issues but for some reason this one is intermittent.

As was mentioned before you might have sucked up some crud in the fuel system and hopefully you are running a fuel filter on the line before it gets to the carb. I've had a small sliver of silicon tubing give me fits as it lodged against the dubro filler valve inlet causing an intermittent blockage from hell that was all but invisible inside the cowling on a plank Cap 232.

T