Every engine has to be tested new out of the box. I have had mine in my Great Planes Ryan for 2 years now. I bypassed the needle valve and put an inline needle valve there. I also found that Byron fuel was causing problems for me until i switched to a pure castor blend. My Ryan after 2 years runs like a top. But to the gentleman that commented on people having to fix there engines that is an irrelevant comment. If you are looking for products to be perfect out of the box than you are looking for the wrong things out of this hobby. What engine in the world doesn't need work??? I sit there at my field and watch people tinker with there engines on the ground for hours until they are running just right. Just because an engine runs good on the ground means nothing to its performance in the air. O.S. engines remote needle valve SUCKS there is no good way to put it. However if you spend a little time working on the engine you won't find an engine anywhere that will outperform an O.S. Just my little food for thought.

JEFF

I have 3 ..One NIB, ...........One just installed in a GP big stick ..........one in a GP shoestring........The one on the big stick is a P>O>S> the head came loose last night .....This motor has NEVER run good ....the one on the shoestring run like crap at first....Mass tuning has brought it around ,but still not 100%......#3 is NIB so I have no com on that one......JW

my 91 fx also ran like **** until I throwed out the #8 plug and replaced with a Fox miracle plug. THings started happening then . This engine also required a long break in and a tweek on the low needle.