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Webra 50 dies in spins

1294 Views 10 Replies 4 Participants Last post by  PaulSwany
Ok, here's the problem... I have a webra 50 w/ stock muffler running a apc 12x4 on an omp edge 540. The fuel tank is right above the carb. I can fly around just fine, harriers, torque rolls, knife edges.... engine never sags. Then second I try to put it in a tumble or a spin, the engine starts to run rough, and if I don't pull out and throttle back it will die. I just changed the glow plug out to an os #8, and I run omega 10% through it. Any thoughts or suggestions?
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Is your clunk real close to the back of the tank?? Maybe it's getting slung up against the back of the tank or something...
it is pretty close to the back..... how far would you suggest that i keep it away from the back of the tank?
1/2" or so I'd think..
Check the length of your fuel lines. Try to get the shortest possible path. If they are too long.. the engine will have trouble drawing fuel... You might also check to see if the tank it strapped on too tightly. If it's too tight, the vibration from the engine is transfered directly to the fuel and it foams up causing the engine to lean out.
hmmm, ok.... what's the prefered meathod to strap a tank on? I've just been using zip ties.
I like rubber bands cause it alows the vibration to be dampened and not directly transfered to the tank.
how do you fit the rubber bands through? Do you just go all the way around the fuse?
Screw some eyehooks into the fuse an strap from them . Thats a fast easy way to do it. Im sure it could be done more professionally if you didnt want that.
Ok, did some more talking with the local engine guru, and he suggested that the pressure tap was in a bad spot, and in high g moves there wasn't enough pressure on the tank to overcome the g forces. It was suggested to move the pressure tap out on the muffler isntead of the manifold, right where the muffler starts to narrow. Since this is a point of restriction, you would, in theory, get more backpressure. Does any of this make sense? Doesn't take much to drill a hole and tap it, and even easier to put a plug in, but I was just curious as to what you guys think.
I've had better luck with Webra's other muffler style..... the one that looks like a canister rather than a torpedo.....

I'm assuming you have the torpedo muffler as that's the one with the pressure tape on the manifold... Jerry Smith recommends this place for pressure taps on his mousse can setups.... He grinds a "V" into the pressure tap to act as a scoop for the incoming pressure...

The first Webra I had used to sag when I would knife edge with the tank below the engine. I decreased the length of my fuel lines and loosened the tank mounting and it didn't sag anymore.
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