[NSRCA-discussion] YS-160 setting

[JShulman]

Thanks Troy for my answer. Hope everyone out there got what they needed out
of that detailed part before the answer ;) I'll report back tomorrow. or
have to replace the motor...lol.

Regards,
Jason
www.jasonshulman.com
www.shulmanaviation.com
www.composite-arf.com

-----Original Message-----
From: nsrca-discussion-bounces at lists.nsrca.org
[mailto:nsrca-discussion-bounces at lists.nsrca.org]On Behalf Of Troy A. Newman
Sent: Thursday, March 08, 2007 10:34 PM
To: NSRCA Mailing List
Subject: Re: [NSRCA-discussion] YS-160 setting


Jas,

lean the pump a little bit about 1/4 turn and see if the motor starts to go
lean in the transition.
The way this engine works is the pump pushes the same amount of fuel all the
time. Every stroke it pushes the same volume of fuel. If the engine is at
idle and not using the fuel then pressure builds up in the injector line
until it gets to that magic pressure where the pump pressure screw allows it
to bypass back to inlet of the pump. So everything the engine doesn't need
gets pushed back around to the inlet of the pump for the next gulp.

If you are at idle, and the pressure control on the pump is too tight
meaning not allowing enough to loop back around it will got in and get burnt
and come out as lots of smoke at idle. Yet when you are at full power or at
least upper end power the HS needle is set and the mixture is correct.  So
what is happening is you have too much going to the engine and not enough
bypassing around.

Lean the pump...CCW. If you get to lean on the pump is will start to
detonate on throttle up or will sit and surge at idle. To be honest the pump
setting are actually pretty broad and the engine will run correctly with
many different setting. The key is the pump always moves the same amount of
fuel. You are not adjusting pump pressure, you are adjusting the pop off
pressure. Meaning the pressure which the little diaphragm will allow fuel to
loop back to inlet. So adjusting the pump richer means more pressure on the
spring and diaphragm so the pressure it takes to allow bypass is higher and
as result more fuel goes to the engine. Less spring pressure on the
diaphragm and the lower the pressure in the injector line needs to be to
allow the bypass and the less fuel goes to the engine because the little
pressure valves open sooner.


If it always pumps the same volume of fuel, and more is going to the engine
it will burn and turn to smoke especially at idle and below 1/3 throttle.

Now that explanation was for everyone else. Here is the Jason answer.

Turn the little brass screw on the front 1/4 CCW and see if it helps! if it
surges at Idle you went too far.

Troy


----- Original Message -----
From: "JShulman" <jshulman at cfl.rr.com>
To: "NSRCA" <nsrca-discussion at lists.nsrca.org>
Sent: Thursday, March 08, 2007 5:06 PM
Subject: [NSRCA-discussion] YS-160 setting


> Hi all,
>
> I've got my friends DZ and the high end needle is 1 1/8 turns out. The reg
> is somewhere around flush. It smokes and bunch, smooth transition, but
> 20ozs
> in less than 8 minutes if I'm not careful. I remember hearing (being told)
> that there is a less consuming set-up that I haven't done yet. Anyone know
> what it is? Gonna fly again tomorrow and try it. Thanks.
>
> Regards,
> Jason
> www.jasonshulman.com
> www.shulmanaviation.com
> www.composite-arf.com
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