Royal engines were made on the same assembly line as Hobby Shack's original Magnums and had all the same problems. Number one being lousy carburettors. Jerry Toppel was the west coast rep for Royal while I was working as Hobby Shack's engine tech in San Diego. We both agreed that quality control and both lines was spotty at best. The biggest dofference was Royal knew the problem and made sure the engines they sold worked reasonably well. Hobby Shack just sold them all and then took them back under warranty.

OS did not "overcarburate" their engines to run at "insane" rpm. The average 40/45 ran at about 13,500 which was about normal for a 10x6 11x5 prop. Nothing spectacular but good. The max rated HP was 17,500 for anOS45FSRABC but the torgue curve was highest at the 13,000rpm level where most were going to be used.

Most GOOD two cycle engines don't have that problem. The OS 28 FSR transitions beautifully as do 99% of OS carbs. Same with Enya and other Japanese engines. The 4B, 4BK, 4D 7M 7L, 2D and most of the OS carbs have excellent transition.