Webra Problem

[Keith Black]

Three turns out on the high-end needle, holy smoke! You must have your pump pressure really low or have pump problems. My needle is around 1.5 turns or less out. I'm wondering if the previous owner didn't switch to the OS 140 because he just couldn't get the Webra adjusted correctly? If this is the case he may have messed up the settings on the pump. It doesn't sound like your pump is old enough to have worn out, maybe it has debris in it. Do you, and did the previous owner, use a fuel filter in front of the pump?

Another thing to watch out for is poor performance due to bearing wear. When I first started running the Bully/Webra I was pleased with its performance after some of the local guys gave me some pointers on how to get it tuned correctly, but toward the end of the season when the weather got a bit cooler it stopped running very well. I assumed the weather change required adjusting the mixtures but I just couldn't seem to get it right this time and often it would bog down at the top of uplines. Then suddenly one day it died in mid air and when I landed I found that the prop could barely be turned, the bearings had gone out! The poor running prior to this was a warning sign. Luckily there was no major damage to the engine and upon changing out the bearings my good running motor was back to its excellent performance and I no longer had any adjustment problems.

I'd open the engine and look at the bearings, also, as Lee mentioned, if you can't get it really rich you probably have a pump problem, three turns is far greater than what I've seen on the needle adjustment. As to the tank placement, you don't need to move it to the firewall if the pump is working correctly. 

If you have someone local that knows a lot about pumped pattern engines then I'd suggest you seek their assistance.

Good luck,
Keith Black

  ----- Original Message ----- 
  From: Randy 
  To: discussion at nsrca.org 
  Sent: Thursday, June 10, 2004 10:01 PM
  Subject: Re: Webra Problem


  I got the engine new used last year.  It ia a AAR.  Did not fly that much last year; but the engine mostly ran well.  Sometime go a little rich and lose a little vertical.  Has been less reliable this year after the winter.

  Throttle up before vertical and bogges part way up about half the time.replaced fuel tank earlier this week.  Turned pump pressure in one turn today.  Have high end around 3 turns out.  I see smoke on the ground, but much in the air.  Seem to bog more on the latter half of the tank.  Moved tank to just in front of wing tube to shorten line to pump;but did not see any change.

  No idea how many flights before I got it, but not that many as owner decided to stay with OS 140.

  I am going to clean carb out in the morning.  And check to see if the pump pressure is at four threads.

  Randy

    ----- Original Message ----- 
    From: Keith Black 
    To: discussion at nsrca.org 
    Sent: Wednesday, June 09, 2004 2:12 PM
    Subject: Re: Webra Problem


    Randy, 

    Is the Webra new (or new to you)?

    Has it been running well and now it's not doing so well or has it always had problems?

    Has the pump ever been adjusted since it was new?

    When loosing power on the uplines is it wide open then bogging down after being in the upline for a while, or are you increasing throttle while in the upline and then it's coughing?

    How much smoke does it blow when wide open in level flight?

    How many flights do the bearings have on them?

    Keith Black

      ----- Original Message ----- 
      From: Randy 
      To: discussion at nsrca.org 
      Sent: Wednesday, June 09, 2004 12:55 PM
      Subject: Webra Problem


      My webra 145 with a normal carbo seems to be losing power on the up lines.  It seems to me that the pump should delive a near constant flow of fuel.  So I should not need to have is real rich on the high end to handle the up lines.  But still losing power on uplines, so have been richening it.

      Low end seems fine.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://lists.f3a.us/pipermail/nsrca-discussion/attachments/20040611/1b8c4cf7/attachment.html