tonyjambo

Hi,

i have a YS63FZ that up until recently was behaving itself nicely - then it started refusing to run - it ran great if you put fuel straight into the carb but refused to run consistently.
Today I replaced the regulator diaphragm, replaced the plug and double checked all the fuel lines.
I have good pressure to the regulator intake - if i pull that hose off then the fuel spews out under pressure.

So today after replacing the regulator gasket I set everything to the following:
Regulator screw out 3 turns
Bottom end out 1 1/2 turns
Top End out 2 turns

I turned it over by hand about 10 times with the throttle at idle then turned it over by hand 10 times with the throttle open.

Put on the glow and turned it over - it started first time and kept running.
As I tried to throttle up the mixture seemed to lean out a bit so i richened it up - then over about 1/2 throttle it started sounding like it was pre-detonating and then shudders to a stop.
When it stopped there was fuel spewing out from the carb and i could see it still coming from the regulator to the carb intake.

At this point I'm stuck - it seems like to run at the bottom end I need the regulator screwed out a long way but as it gets to the top end it needs to be screwed in more in order to be able to regulate at high pressure.

One really simple question - the regulator case has a raised ridge on it - should that be facing forward or backward ?

Any ideas what I should try next.

For what its worth I'm running a 12x7 prop which gives me about 11,500 rpm at the topend (when it runs)
I tacho'd the idle today and it was idling @ over 3000 rpm

Thanks
Tony

Richard L.

My Feedback: (24)

Your midrange is way too rich and your top end is too lean. Close the regulator screw about 1/8 - 1/4 turn and open up the top end a couple of clicks.

tonyjambo

thanks - i'll give that a go

JohnW

My Feedback: (6)

You might have the regulator on backwards. When it is on backwards, it will hang open, and empty your entire fuel tank into your engine really fast, which sounds like what happened. With engine off, there should never be fuel getting past the regulator. Check the key (small tab) on the regulator. I believe it is to point forward, but double check your manual.

huey-pilot

My Feedback: (17)

The tab on the regulator housing goes forward.

Lancair-RCU

The regulator is your problem. I cant remember which way it goes on now, but reverse the way you have it.

I had exactly the same issues with my 63FZ.

Ive seen the light now and dont own a YS. They're awesome when they run properly, but as my mate kept saying when I had problems, "YS means Why Suffer ? "

tonyjambo

thanks guys - yes the regulator was on backwards - nice of them to put the little tab on it but would be even nicer if they told you which way it should face