[NSRCA-discussion] OS140rx problems - help needed.

[Scott Smith]

Regarding the bearings, I recently contacted a local bearing supplier
(www.ebatmus.com 1-800-666-6761) after seeing they had the 6904LLU listed in
stock for $35.99 on line.  The phone quote I received was $19.  After
mentioning I could get these for $12 elsewhere, he agreed to sell them at
that price.

Anyway, when I went to pick it up, what he was selling was a generic copy of
the NTN (explaining the liberal pricing.)  He assured me it was every bit as
good as the NTN.

This bearing had black seals instead of the orange and more importantly,
spun very easy compared to the NTN.  I'm not sure if it's the grease or
construction on the NTN, but they have significant drag at room temperature.

So in went the black sealed generic bearings (I did the front as well).
I've got ten flights now with them and both the power and fuel mileage has
gone WAY up (15 minutes yesterday on 15 oz of fuel, this same engine was
doing 10 minutes on 18 oz)  Static RPM increased from 7,800 to 8,200.  I'm
liking it!

The only question remaining is whether they will hold up...

Scott
(Sorry, I failed to write down the markings before installing these
bearings)
  -----Original Message-----
  From: nsrca-discussion-bounces at lists.nsrca.org
[mailto:nsrca-discussion-bounces at lists.nsrca.org]On Behalf Of colin
chariandy
  Sent: Saturday, April 29, 2006 12:13 AM
  To: NSRCA Mailing List
  Subject: [NSRCA-discussion] OS140rx problems - help needed.


  Hello

  I started having problems with my 200-300flight old rx last season after I
lost my muffler ( Bolly 460) in flight. I decided to upgrade from a muffler
to an Aeroslave pipe. The motor ran poorly on the pipe and I blamed the
set-up. Poor midrange required that I back out the pump 3/4 and set the top
end a bit lean for reliable operation in the air. The setting would change
from one flight to the next. On the ground the engine would load up and
eventually quit 1/2 the time. I have now gone back to a muffler ( Bolly 590)
and the engines runs exactly the same as on the pipe...very poor mid-range,
erratic operation.

  Previous bearing replacement was the stock item put in 50 flights before
the problems started.

  I'm going to guess I need to replace the main bearing. What should I buy
and where? What else should I check/replace ? When should ring/sleeve be
replaced? Does anything else go wrong with these engines...pump problems ?

  All inputs are welcome.
  Colin.




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