Let me tell you a story from my G90. Ive had two of them and they're very good engines. A couple years back i had my first G90 in the little WM P-51. What a mover until its untimely end from a battery failure. I had over 200 flights on that baby.
Anyways, the first 10 flights were miserable. Ground run ups were perfect. Get it in the air and a minute later it overheat and come in with my throttle full open and engine is at an idle. I went over everything and even sent it in to Hobby Services "twice within a month and they found nothing!
Got it back again and re installed it "again" and flew it again and it overheated again and I got &^%$ again! So I took a long hard look at it "again." I noticed my fuel line from the tank to the carb came out as normal but it curved around and such. I took a guess that there was to much curve and that my line maybe pinched.
So I made my fuel line longer to sure there was no pinch and that was it. Over 200 flights without a problem. So check the fuel line. It may not look pinched enough to cause a problem but it might.