Viper Driver

My Feedback: (1)

I have a 140 DZ that has about 5 gallons through it and it has just recently started a new problem. I make it through 1/2 of the masters pattern with the motor running great until the top hat with 3 of 4 up, 1/2 down where it dies when I push up the power. If it doesn't die there it dies in the next maneuver. I have replaced all of the fuel tubing including the clunk line (which was fine), tried new plugs, increased the idle speed all with no consistant success. About every fourth flight, it runs all of the way through. If I do the top hat with a full tank, no problem, so this leads me to believe it is a fuel draw problem with about half a tank. I am running a 20 oz Tettra with the gray foam clunk. I guess I could go with a bladder type tank, or use a header tank to fix the problem, but why did it only start doing this in the last week or two. Any suggestions I might be overlooking? The idle is very consistant on the ground and for the first half of the flight.

Thanks,

Jeff

Adamg-RCU

Jeff, the only time I've had my DZ quit in one maneuver repeatedly was the vertical eight in P05. It turned out to be the clunk sitting too far back in the tank, and not being able to move right to the top of the tank in the hard push. As for what changed, the gray clunks do expand as they get older. Also, how hot is your spinner when you land (to the touch)?

Divesplat

My Feedback: (7)

Hey Jeff. Was great to meet you in Alb. Hope to see ya soon.

Agree it sounds like a fuel draw prob. I haven't had that prob with my Dz's. Wonder if your clunk line is too short or too flexible??

When I was first learning the Dz I would get it too lean(I think) and 1/2 way through the flight it would just die. I would adjust the regulator and it would improve. Can't remember which way I adjusted though.

Hope you get it fixed.

ed

Viper Driver

My Feedback: (1)

Looking forward to your contest Ed! I did check the clunk upsidedown and it was hitting the top corner a bit, so I shortened it, but it didn't help. It could be leaning out, but if it makes it through those maneuvers, it runs for the rest of the flight, so that makes me think it is fuel draw. When it does quit, it doesn't just die, it seems like it is motoing at a high idle, and it won't respond to throttle input, which if memory serves, is what it did the one time I did run it out of gas.