Berk

Hi,

I have a FZ140-S with about a Gallon and a half through it.... nice constant smoke throughought transition and top end, and will idle for about 20 seconds, after which it 'loads up' rich and dies... regulator is set flush..

I'm 3.5 turns out on Idle needle.. I don't know if I should go out any more? I did see a mod where people have drilled out a Hole on the Carb, but i'd rather not do that!

Or is this just a case of the engine being new and just needs running in some more?

Regards,

Steve

Dave Shadel

This engine sounds like it is completely out of adjustment or in need of repair.

Try going to www.ysperformance.com and following the instructions for setting one up.

It might also be a fuel problem. What type are you using?

Berk

Dave,

I'll try resetting the Idle back to 1.5 turns out and trying again ... though it does seem to idle constant speed for a while, then start to go rich... Transition and top end are fine, I'm just keeping the top end deliberately rich.

I'm using Prosynth 2000 20% fuel.

Regards,

Steve

Dave Shadel

Have you checked the valve setting? Needs to be .003" on both.

Another thing to try if it's dying rich is to reach into the plug and pull the coil up out of the cavity about half a mm or so. It will make the plug stay hotter at idle.

Berk

Valves are set right.. at .003, I replaced the plug as I thought that was the problem, but wasn't ....

What's an acceptable range for the idle screw other than 'whatever works '??

I also seem to be trying to idle at 2000, whereas maybe I should be aiming at 2500!

Regards,

Steve

Dave Shadel

Idle screw usually falls about 1.5 to 2 turns open.

I seldom shoot for 2000, most of them won't do it, so I go for 2300 to 2500. Works better for me. At that rpm you are into the regulator a bit and it seems to help.

If you continue to have problems try stretching the plug as I mentioned. It's not as stupid as it sounds.

Berk

Thanks Dave, 2500 is attainable without further adjustment... it seems as if the plug is cooling down quickly below this RPM!

I'll leave well alone and keep a high idle, or try the plug stretch if I need a lower idle!

Regards,

Steve

Dave Shadel

Good Flying!

Berk

Dave,

I took off the YS Air filter to find lots of fuel spilling out at Idle..

Regulator needed to go in 3/4 turn from flush to stop this.

Upshot is, engine is running great, still a little rich on the idle,even 3.5 turns out! 8700rpm with a 17*8

idle is now a solid 2000

still a plume of smoke at transition too..

Thanks for your help

Regards,

Steve

Dave Shadel

At 3.5 turns out the idle needle is essentially non-functional. I heard of one being drilled improperly that would still be rich at any setting. This could be the problem.

Glad you got it sorted out, happy flying.

Berk

Dave,

Do you mean improperly drilled in manufacture? how should I check this? I have not attempted to drill anything! But yes, essentially the Idle screw does appear to have little effect.. I can not lean out the idle at all! I have effectively set the idle with the regulator screw..

Regards,

Steve

Dave Shadel

Pull the throttle barrel out and have a look at the hole that the idle screw goes through. The screw should be centered in the hole, not off to one side.

Another problem we've seen (although not on the 140) is that the hole is drilled too deep and when you seat the idle screw all the way in it takes 2 or 3 turns just get it to start opening the hole.

Let me know what you find.

Berk

Dave,

It takes about 1.5 turns to see the end of the dome of the low end needle in the hole.. it continues a little past the hole!

The hole is also off center as there is a space above, but not below the air bleed screw, as you look through the hole.

Upshot is, the air bleed hole is opened to around 60% (2/3 of a moon shape) where I find a good (yet still slightly rich) idle..

Should I replace this Barrell in due course, or not worry about it? or get it changed at end of season service?

Boy do you know your stuff!!

Regards,

Steve

Dave Shadel

Nah, just leave it. YS strikes again!

Let me know if I can help.

Berk

I finally plucked up courage to drill the air bleed to 1/8" (Hard to find in UK!!).

Problem solved. Now it idles nicely at a sensible low needle setting!

Thanks Dave!

Regards,

Steve

Dave Shadel

Great!

Good Flying!