Hey guys, I have a DP 120 Ultimate with a Webra 120 on it. I have had vibration problems since the beginning . The kit includes a nylon engine mount that I used but it seems too flexible. Not only do I have the vibration problem , but the Webra seems to "load up" in the midrange with the upper and lower ends set as good as they can be. I am running an OS "F" and cool power 10%. This engine is on its second plane and has been treated well. So I don't know if the vibration contributes to the engine problem or if they are two seperate problems. What's the best way to contain the vibration and does anyone know what could be making the webra run so rich?PS I'm running a Balanced mejlik 16X8 and a Dave Brown Vortec spinner.


The poor airplane is coming apart!!!!!!!!!!!!!!!

Help!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

First my Webra 120s don't like more than 5%. I lean the idle a little more than lean to keep the mid range from loading up. But there are are still throttle settings that will get a little rich. I haven't tried it yet but a couple of good pattern guys that run 2 cycles say to use a uniflow tank on 2 cycles that tend to richen a little in the mid range. I'm going to try one soon.

just wondering how the engine is mounted...inverted,90 degree or what?

It's mounted 90 deg.any ideas on how to isolate the vibration should I get the engine running right.


MIke

Thanks for the info, where could I find that type of tank?

Lowns, when I first got my 120 I thought I had that problem also but eventually got it sorted out. But I discovered that the carb off of my Irvine Q72 has the same neck and venturi diameter as the Webra 120 carb and made it throttle like a rheostat. But as mentioned I got the stock one figured out by tweaking until I got it.

Any tank can be a uniflow tank. Simply hook the vent line up inside the tank like another fuel pick up line without the clunk. Tie the 2 fuel lines together with a piece of loose fitting shrink tube so they stay together as they move around the tank.

If your plane has the fuel tank on centerline with the spray bar or nearly so you can test to see if this will work before doing it. Fly your airplane inverted in a race track pattern. A normal tank inverted is a uniflow. Your engine should be slightly leaner inverted. If while inverted your mid range rich problem goes away the uniflow tank will work upright or inverted.

How then does this tank vent air while filling with fuel?

RJ

A third line (2nd vent) that you plug after fueling

Mine did the same for the first gallon. Was worse on 5% fuel, better on 10%. The motor needs CASTOR, and the directions state this. Coolpower isnt recommended. Use fox 50/50 5%, runs great. Wonderful motor!