Well----------no. You've answered your own question.

Manual says 18% and you got 14% oil.

Smaller engines require higher oil percentages. You can get away will less oil in bigger glow engines, like the Super Tigres and Mokis. But, for a little .12 engine--I'd stick with the 18% if thats what the manual tells you.

I even add EXTRA oil to my fuel when I'm doing the break in. I try and break my engines in with 22% total oil content.

Just buy a quart of Klotz de-gummed castor oil from Tower or the LHS and add 6oz to your fuel jug and that will bump your oil up to just a little more than 18%.

If you want to bump it all the way up to 20% then add about 7.5oz--maybe 8oz.

If you want to bump your 14% oil up to 22% then add about 10 or 10.5oz of oil to your jug.

All my calculations are based on a 1 gallon jug

Break in is the most critical time for an engine. Having AT LEAST the recommended amount of oil in the fuel is crucial. Having a few extra ounces of oil in your fuel during break in won't hurt a thing. I'm a believer in adding oil when doing the break in.

But, doing your break in with 4% LESS oil than recommended by the factory is a disaster waiting to happen.