Webra Problem

[RC Steve Sterling]

All it takes is a speck of contamination in the pump diaphrams-- I just had
a very small speck of plastic (hair size) and it didn't pump well. Cleaned
it out, all was well. Aways run a filter before the pump. This one got by my
filter.
  -----Original Message-----
  From: discussion-request at nsrca.org [mailto:discussion-request at nsrca.org]On
Behalf Of Keith Black
  Sent: Thursday, June 10, 2004 10:46 PM
  To: discussion at nsrca.org
  Subject: Re: Webra Problem


  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.
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