Dave,

First I would like to thank you for having this direct line in the RCU forum. Having it is one consideration I use for purchase and one of the reasons I chose to buy the FZ110, my first YS product, despite what others said about they being finicky. I loved the engine in my Funtana 90 for the first 3 or 4 gallons of Powermaster 20/20, nice power and cool looking smoke trail (I assume this is natural result of the supercharging, since it was present even when running a little lean). Last three flying sessions have been a nightmare though.

It all started one day with the engine acting like the low end was rich, ie dying with the application of throttle. I also found when I could get it to run at high throttle, engine rpm surged up and down. Adjustments of the needles and fuel regulator did not cure the problem, and when I finally decided to take the regulator apart, found a small pebble, approximately 1/64th" square. Cleaning that out and reseting the needles the engine ran well enough to take a flight or two but it still not right based on the following.

-No matter how much the high needle is richened, there is no smoke in the exhaust
-There seems to be less power at the end of the flight than at the beginning.
-While I don't have any bubbles from the fuel tank to the engine, I do have some from the regulator to carb. More at low throttle, fewer at higher settings. There doesn't seem to be any holes in the diaphram.

Your comments/suggestions will be appreciated.

Sincerely,

Frank

Tried adjusting the valves yet?

Did you just crack open a new can of fuel?

Are you using fueling valves?

Thanks Dave for the quick response! The valves have been adjusted, 2 brand new cans of fuel with different batch numbers, 2 new glow plugs and no fueling valves (just the recommended setup described in the manual). No leaks in the lines or tank, check valve works.

Could I ask you this, would tank pressure problems cause this, ie no smoke in the exhaust, and low power? Needle was gradually opened as I mentioned, I just checked how far, would you believe 4 turns out on the high needle? On take off, there is plenty of smoke, then nothing. I have a Tetra tank which I want to replace the stock tank out. I'll do this right now if that makes sense to you.

Flimsy tanks won't work, and cause all kinds of problems. Swap the tank. The HS needle should run at at 1.5 turns open. Something is very wrong here.

Go to www.ysperformance.com and follow the running instructions.

Let me know.

Done Dave! I will definitely let you know how it goes. Thanks!

OK

Hi Dave,

So this weekend I went with the Tetra tank, things are slightly better, also found that the one way valve was a little loose. Unfortunately, the motor is still not running right. I can start it ok, adjust the high needle for slightly below peak and all seems to run normally for a minute or so, transitions from idle to high throttle beautifully. Then the rpms start going up and down. At this point going from idle to full throttle, the engine will turn about 3000rpm then take about 30 seconds or so to throttle up, or just bog down and quit. Engine can't be restarted until it is cool and I release pressure.

You may recall that my problems started with a very small "pebble" in the regulator. I'm tempted to replace the diaphragm, but on the other hand I've gone through a gallon of fuel tweaking all the adjustments and want to send the motor back for servicing, especially since you mentioned in another thread that one could replace stuff left and right and not get closer and that your staff are experts.

Frank

Send it back. The address is on the instruction sheet.

Sorry for the problem.

Will do Dave. BTW no apologies necessary. I'll be happy when you get the engine running right, its such a perfect match for my plane and feels good. In the end, I'll be a better informed user, ie if it happens again I'll have a better idea what to do.

Thanks

Dave,

I just got my engine back! I must say that you guys have fast service! The note on the invoice says I had the regulator on backwards! Sorry about that. At least I'm better informed now and probably won't have the same problem again. Additionally, I found that the diaphram, all gaskets and the ring were changed out, all under warranty!! I feel obligated to buy more YS motors. I do need another one so I'll order just as soon as I how this one runs now.

Thanks again!

Frank

Let us know how it works for you.

I have a related question Dave - I took my regulator off yesterday (110) and ran into a similar problem - how do you tell the correct orientation to re-install it? There seemed to be a little blob of metal on the regulator in one spot, but I couldn't find any matching registration marks on the engine to line it up. The motor seemed to run ok when I re-installed it, so I guess I got lucky.

More questions: The diaphram in my 110 has a small fold or crease in the middle. When you first take the reg off, you can see a bubble of air between the diaphram and plunger under the crease. Is the crease supposed to be there, or should the diaphram be completely flat?

I am having some problems with the way the motor runs, and I am taking the advice you gave a number of other folks and ordering the replacement plunger for the 91 (I'll get a few diaphrams and springs too). While I'm putting in an order at Central, I could use some fuel too. Would Magnum's YS 140 DZ blend be a good choice for the 110FZ? From Magnum's website, it appears to be a 30% nitro blend, but I don't know the other additives (assuming low viscosity lubes like heli fuel?). I've been running Coopers 30% Plus grade, but Brian is not yet back to producing fuel since he moved to NY.

Thanks,
Kurt

The diaphragms are never flat after being run. The important thing is that they have no tears or holes. The blob of metal or the regulator housing goes forward as you have found.

The DZ fuel works well in any of the YS engines, Cool Power 30% heli and Powermaster 30% heli work well too.

Thanks Dave.

After I posted that message it occurred to me that I have a second 110 NIB that I bought during the last production run. The regs are different! The newer reg has a bit of metal that should face forward as you mention, but my older one does not. The "blob" of metal that I referred to on my older one is in a different location. See the pic (this pic was meant to show you the crease and bubble in the regulator, but you can see the "blob" I was referring to on the left).

I also noted that the newer 110 has the 91-sized plunger in it! I guess they decided to switch back!? There is also a gasket on the newer one, but not the older.

Thanks again for your Sunday reply. I'm going flying now!

Kurt

pics: older reg left, newer reg center, older reg right

The newer 110 has 120 regulator. Works much better.

Dave,

1) What do you mean by a 120 regulator, being the 120 is not made anymore? And don't keep the details secret....why does it work better?

2) How much difference would there be for a 110 running the newer block nib regulator (with small plunger) or the older reg with little nib and (?) plunger?

It's really no big deal. Neither one makes more power than the other. The 120 regulator fixes the problem of plunger sticking that we encountered in some of the 110's.

If your 110 works fine the way it is, the reg from the 120 won't make it any better.

So how do you identify a 120 regulator? Is it the big nib or little one?

In the picture posted on the left, the reg is on backwards. Note the different passage shapes on either side of the reg, one is straight, the other is rounded as witnessed in the right hand photo.

You know, I think you're right. I can swear I had 2 or 3 flights after re-installing the reg yesterday. Will the motor run with the reg installed backwards Dave?

As for which reg has the little nib, I can only speak of the 2 regs I have. The small off-center nib is on the older, large plunger reg, and the larger centered nib is on the newer, smalll plunger reg. I'm not sure if that is universally true, maybe Dave will chime in.

Kurt

EDIT: I added a pic with the older reg reversed compared to the pic in my previous post. Now the little off center nib faces the front of the motor.

Ok, my new question is, do I want to replace my old large 110 plunger with the 120 version or the 91 version? My newer motor has the 120 version, but if the 91 version will work I think I'd prefer it since I wont need to worry about ever replacing the reg gasket. It appears that the reg gasket used in the 120 reg is only available in the $10 gasket set, and the 91 version doesn't use a gasket.

Will the 91 plunger and diaphram work in the 110? Any reason to chose the 120 version over the 91 version?

Kurt

IF your engine is running OK, don't change anything. If you are having problems, check with Richard at service about switching over to the 120 reg. His number is 775-782-4562.

Dave,
Sorry to chime in uninvited... I can start a new thread if needed.

So how would you identify what reg is installed on a used 91 / 110 / or 120 motor for example?

The 120 reg is the photo on the left and right above. Middle one is 110.