My G-61 ringed engine broke in fairly quickly last fall. Three tanks on the ground and it was reliable enough to fly without worrying about deadsticks.

I found that it liked a hotter plug, however. The Super Tigre plug that comes included isn't a bad plug. It's a medium heat plug, however, and doesn't offer the best performance. With 10% nitro fuel, you might find that an O.S. A3 is the right choice for better idle and smooth transition.

With regard to the engine dying after a few seconds to a minute, I'd pay very close attention to how hot it's getting. If the engine is barely warm when it dies, it's not likely to be an air leak. That would be more indicative of a rich setting on the low end. If the engine is very hot when it dies, then you probably have an air leak.

On a newer engine, just because the tuning was spot on a few tanks of fuel ago doesn't mean that it's correct now. Glow engines tend to continue to break in little by little over time, and a good low end setting now will be too rich two or ten tanks of fuel in the future.

The last thing to consider is your oil content. 25% all castor is a wonderful choice for the first couple of break-in runs on the ground. Once you get done with the basic break in on the ground, however, you're just robbing yourself of power. 18% to 20% oil content is plenty once the first two tanks of fuel have been run through a brand new engine. 25% all castor fuel is normally only used in 1/2 A or plain bearing engines and is too heavy on oil for a normal ball-bearing 2-stroke.

I'd guess that your engine isn't hot when it dies after running for 30 seconds or a minute. I'd guess it isn't even warming up that much. If I were you, I'd get some 18% oil content(all castor or blended, but not 100% synthetic lubrication), 10% nitro fuel and run that with the current plug. If you're still not happy with the results, then go to a hotter plug like the O.S. A3 or the Fox Miracle plug. From there, you should be able to adjust out any minor tuning issues by adjusting the low end needle after re-peaking the high end needle then turning it rich of peak by a quarter of a turn.

Changing the fuel will affect your tuning. Changing your glow plug type will affect your tuning. These adjustments will take a little bit of work and an experienced hand will make easy work of it. If a flying buddy is handy, get together and get a little help. Even two guys with the same amount of engine tuning experience are better than one; sometimes we get frustrated working with engines and a fresh perspective will often help.

Good luck and let us know how you fare!