cmmicroheli

Ihave a Jett 56lx that seems to be leaning out after about two minutes of flying. I'm running a 9x7 zinger my needles are set as follows mid range is half a turn in from flush and high speed is four and a half out. Motor seems to come and go as it runs well some times and other times it does not. I have also pressure checked the tank and itsfine. Any help would be appreciated.

bob27s

My Feedback: (19)

Hi !

First, needle positions you noted are "about" right, but the only way those are correct is when the engine runs its best. The low/mid mixture is factory set - should not be adjusted until after the engine has run for a while - and in that case turn it no more than 1/4 turn either direction.

Usually when the engine runs erratic or inconsistant, you are dealing with a fuel system problem. With the energy these engines put out, a lot is transmitted to the airframe, and with that, you get a huge risk of fuel foam (even if you do not see it it will happen in flight)

First step - make sure the fuel tank is not touching ANY structure. Foam padding all the way around it. There is no way around this absolute must.

Second - high speed needle setting - find ground peak rpm (briefly), back off from that 800-1000 rpm for flight. When the engine unloads in flight, it needs the fuel.

Which aircraft is the engine installed in? What prop are you using ?

If possible post a few photos of the engine installation and the fuel tank install. That will help me a bunch here.

Bob

cmmicroheli

Hey Bob. I'm running this in a sundowner 50 and I'm using a zinger 9x7 prop. The tank is completely wrapped in foam I did have one spot of interference at the top of the fuselage but Iwas able to remedy this. I will get some pics posted tomorrow. Thanks

vicman

My Feedback: (10)

Fatten that puppy up and give it the fuel as well as a steeper prop.
I know what you are trying to do.

cmmicroheli

Hey vic If this thing gets any richer on the ground Idont see how it would ever fly. Idont get it. I think Ipicked up a female. Some days it runs awsome and others its a dog. Idid find a leak on the rnv and seems to be a pretty good one It was leaking at the packing nut and needle.for the moment i have a piece of fuel tubing over it to seal it up.if it worksI will order some parts to fix it.That may be all the problem right there. I wont find out till later this week though.

bob27s

My Feedback: (19)

Tighten the packing nut. You should have it snug so you need a bit of effort to move the needle. If it is leaking it is way too lose.

cmmicroheli

Packing nut is as tight as Iwant to tighten it. The leak seems to be coming up where the needle passes through the nut.

cmmicroheli

Ill be happy to report the needle valve was indeed the problem. I had a chance to sneak in a few flights this morning and with the fuel line over the needle where Ifound the leak, the motor ran like it did beforewhich is screaming. Thanks for the help.

bob27s

My Feedback: (19)

Great to hear.

Possible the insert inside of the packing nut got cross threaded. Rare but it can happen sometimes.

If you can, send me a photo or three of the aircraft and the engine installation

Bob

richardgerardi

I think my 56 Jett is coming today. Can't wait to see this beauty.