GeraldRosebery

My Feedback: (14)

I have a relatively new (1 gallon gas) ZDZ40. It is turning a 20x8 prop using fresh 93 octane gasoline mixed 32:1 with Pennsoil. Although it starts and runs sort of OK, it is quirky. It idles at 1200 and peaks at 6950 rpm. All the throttle response is in the lower half. It reaches 6900 rpm at about 1/2 throttle and then gives no more than 50 rpm more at full throttle (???) The Low End needle is fairly responsive but the High End needle can be turned 1/4 turn either side of what appears to be peak rpm with little effect on the top end. There is a mid-range burble that cannot be eliminated. If I get it to go away with Low End mixture adjustment, the engine will quit on fast throttle opening showing it to be leaned too much. Comments?? Thanks to all.

AirWizard

My Feedback: (3)

I wouldn't worry about the midrange burble until the engine is broken in. As for being at full rpm at 1/2 throttle I see this a lot on gas engines usually you can fix this by adjusting your linkage and making it more linear or if you have a computer radio use a throttle curve.

arobatx

You started two threads with the same question....I answered in the other one:

http://www.rcuniverse.com/forum/m_79...tm.htm#7922503

Chad