WEBRA 120 TRANSITION PROBLEMS
 

Hi

I´m getting problems in transition and idle of WEBRA 120 pumped motor.

High speed O.K. but when throttle back and keep in 3000 rpm motor died. Also transition is not good and died. Tried a lot of idle needle setups but unsucessfull.
Engine is brand new. Webra instructions says it will be good in idle and transition only after break-in. I have almost 40 min run in now.
Prop is 16x6 and plug OS F type. Muffler is Bisson sport.
Any trick??
[:o]
Thanks in advance

Paulo

RE: WEBRA 120 TRANSITION PROBLEMS
 

Do not make big changes in the lowspeed needle, a little goes a long way and it's easy to miss the sweet spot. If it is stumbling and then quitting, it is too rich, if it quitting instantly it is lean.

RE: WEBRA 120 TRANSITION PROBLEMS
 

Mine is the regular Webra Speed 1.20, not the pumped, but from experience with it, I concur with the previous post. be patient with your adjustments to the needles, and use SMALL adjustments especially on the low speed needle. One thing I should point out is that even after about 8 years on mine, it has NEVER had a perfectly smooth transition. That is not to say that it dies all the time like you describe, because mine certainly does not. It runs great, has awsome full power and great idle, it is just that I could never get a perfect transition from idle to full power. It just sputters a little going through mid-range, and is worse about it if I advance the throttle more slowly, than if I advance power more smartly. In all these years of flying it, I can actually only remember it quitting in flight once, so it isn't a big deal, it just sounds funny as it transitions. It kind of "clears it's throat" and then comes on up. Just FYI, I am using a regular K&B 1L plug, low nitro (5%) fuel, and also a pitts style muffler, though mine is an older "J-Tech" unit.

Good luck, Lee

RE: WEBRA 120 TRANSITION PROBLEMS
 

Thanks guys

I have to be patient cause motor is so new.
Next weekend will try and fly again. Engine is installed in UCD 60 and flew once last weekend and died after 5 minutes fly.
Seens to be a perfect match for this plane.
I have also a Dynamix carb spare and wondering to try in this motor. The original carb is the TN II.

Thanks

Paulo

RE: WEBRA 120 TRANSITION PROBLEMS
 

The Dynamixes are "considered" tricky to set up correctly (I still wonder why...).
Just remember that the idle is the other way around: screwing in is rich, out is lean.

I'd stick to the TN II for the time being though, they are excellent carbs.

Give it some time and like others said go easy on the idle needle adjustments.

What fuel are you using? The OS F is kinda hot I think... certainly is you are using nitro fuel.

RE: WEBRA 120 TRANSITION PROBLEMS
 

Are we talking about a four-stroke engine? OS F plug is for four-strokes...

RE: WEBRA 120 TRANSITION PROBLEMS
 

Rudeboy and Gary

I'm using OS F cause I use also in all my big 2 cycles (Mokis)with success.
In the Webra I'm running 5-7% nitro fuel, 19% oil (50% castor 50% syntetic). I usually prepare homebrewer fuel 80/20 and mix with Wildcat 4 cycles (15%N-18% sint. oil). In the Mokis use only homebrewer.
Any other suggestion in glow plug?

Paulo