That is a simple answer....there are big differences between engines and manufacturers.....I have even found that two engines from the same vendor can behave differently......Just saying JetCat is the reason is not the whole picture.

Eg. I have a JJ1400...starts and runs every time.....but no power house and it runs without changing any parameters.....most of the time. I also have a MW-54, the original design, it specs are tighter and it produces more power....but I sometimes need to fiddle with parameters......precision and power from the same basic design means you need tighter controls on fuel......hence you adjust the parameters to meet the situation.

DW_Crash