4-stroke problem

[george kennie]

Bob,
The silicon valve and it's seat look perfect looking through a loop and
it holds back pressure under manual manipulation. The check valve
appears to be operating normally and the condition persists both in the
plane and on the bench with two different check valves.
Thanks for the suggestions. I will probably have to send it back, but
was hoping to avoid doing so.
Georgie

Bob Kane wrote:

> You have tried everything I can think of.  Something is holding the
> regulator plunger open or the little silicone valve or seat is
> damaged. I notice from the manual that the tank is pressurized the
> "old fashioned" way via a nipple above the regulator. Have you tested
> the check valve? Could the check valve be allowing back pressure from
> the tank to get to the diaphram and holding it open?  Just a thought.
>
> george kennie <geobet at gis.net> wrote:
>
>      I'm having a difficult time with a brand new YS-63. Running
>      Powermaster
>      YS-Blend 20/20, 12X6 APC, OS-F. It starts O.K., but when you
>      advance the
>      throttle to full it takes about 20 seconds to slowly build
>      up to max rpm
>      and then if you retard the throttle to anything below 8-9k
>      rpm and leave
>      it there within approx. 5 seconds it will start to "splat,
>      splat, splat"
>      and then abruptly quits, or if you try to advance the
>      throttle it will
>      do the same thing and quit.After it quits, fuel will well up
>      in the carb
>      bowl and overflow like the plunger in the regulator is not
>      seating,
>      however I have inspected the regulator and the plunger
>      silicon valve and
>      everything appears O.K. I can even blow through the feed
>      aperture in
>      the regulator and no air will go through it until I push on
>      the plunger.
>      The are no burrs or any stickiness impeding the smooth
>      operation of the
>      plunger and yet after a short run of a few seconds it acts
>      like the
>      plunger is sticking in the depressed position.I've tried
>      turning the
>      regulator screw as much as a couple of turns in as well as
>      out and
>      nothing seems to help.
>      Anybody know why the regulator seems to be allowing fuel
>      passage when
>      the engine isn't running? I compared the regulator spring
>      length to a
>      brand new unit and it has the same length. There are no
>      holes in the
>      diaphragm and the silicone valve seat appears smooth and
>      does seat and
>      seal manually.
>      It will Idle, but as I recall that's a completely separate
>      fuel
>      circuit.Is there something in the high speed carburetor
>      circuit that
>      could be malfunctioning in such a way that pressure is
>      getting back to
>      the top side of the plunger and holding it in the open
>      position?
>      What do I do here, guys? Eric? Anyone?
>      Thanks guys,
>      Desperate Georgie
>
>      =====================================
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>
> Bob Kane
> getterflash at yahoo.com
>
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