No. The engines reciprocation mass is balanced. Even with an out of balance prop, there would be the same vibration no matter where you put it.

I always set the prop horizontal, turned backwards onto compression.

Hello
Problem with my engine:
engine 200 cdi , prop 21.5x10.5 , fuel morgan cool power 30% heli

While flying, the engine stopped, I landed an emergency landing.

When I checked what happened, I found that an exhaust valve stuck in the open position.

The small piston goes up and down by the camshaft, remaining stuck up

I released the piston I cleaned it and oiled it and now the engine is back to working properly

my question :

Do you also have an event like this?

And what do you think should be done to prevent this problem from coming back?

Tanks

Kobi

I've never had that happen. How much running has it done? It maybe a heat issue, causing it to jam?
As long as the lifter is moving free, there's not a lot more you can do.
If it does it again, I would replace the lifter.

What's the cable tie around the plug cap for?

Hi scott
thank you for the answer,
It's a strip
I tie the ignition cable to the air Pipe like in the picture,
So that it does not move and touch the head of the exhaust
This tying shape prevents the strip from sliding down

There is a grub screw there to lock the cap.

Hi Kobi,

I had a similar event with 185 CDI but luckily mine happened on the ground ...........obviously at a comp on round one.
The engine was new and initially I thought the valve springs may be the issue .......I think too soft compared with 175 CDI.

All I did was to sand the l push rods with fine paper and I have no problems since.

regards

Hi FBW
thank you for the answer
If it happens again I will do it

How do you know if a YS cdi engine is running rich or lean in the air.........?

thank you in advance

If the main needle is lean, it will lose power and get hot.
If the reg is lean, it will sound harsh and horrible. Most likely throw the prop if it's lean enough.

What about if its rich?

A rich reg will cough and splutter in the transition and also top end If it's way too rich.
A rich needle will lose top end power.

Thank you .....

Other than one or two other things I'm a bit dubious about, could somebody please confirm that the hole in the throttle plate that supplies fuel to the sub needle valve on their DZ200 is drilled into the tapered metering slot as pictured? It just doesn't make sense to me to have it there when the taper profile controls the mixture progression as it uncovers an orifice in the throttle body wall.

On my 170cdi, the hole is drilled much further around into the "bulk" fuel slot which directs the metered fuel to the throttle body outlet, so the hole doesn't disrupt the taper profile.

DZ200cdi hole drilled into metering slot, radically changing the taper profile.

DZ170cdi, hole drilled into "bulk" fuel slot, no effect on taper profile.

Thanks in Advance
Brett

What are you dubious about Brett?

Hi Scott,
dubious about a couple of things but mainly that hole location. Even when my engine came back from YS I wasn't happy with it so I put the whole lot away and bought a heli. I've dragged it back out again, stripped it put in a new rear bearing and made sure things are "right" but it still just doesn't want to run "properly" mixture wise.

Apart from the hole location, I also think the throttle plate/barrel isn't sealing in the housing properly either. When you disconnect the injector line from the injector and suck or blow on the injector line connected to the throttle body, air just pours in and out compared to the 170. If everything is sealed up tight, the only way in/out of the injector line is via the main needle valve/pump/tank. It shouldn't be flowing or drawing from anywhere in the crankcase (except via the sub needle if it's open)

I'm rebuilding my 170cdi in case I can't get this thing working as I like.

Like this area (start of red arrows) isn't sealing properly allowing fuel to leak in the direction of the arrows into the crankcase instead of following the channel around to the injector line nipple on the body.

Hi Brett,

I have 2 standard 200 cdi's and a 200S cdi, which all run like Swiss watches.

When you say, you "weren't happy with it", how unhappy does it seem?

It could be possible that the barrel is faulty, but that usually causes the engine to be not flyable at all. Running extremely rough and will not throttle up, no matter what you do with the reg and needle.

I'm more than happy to take a look at it if you want. I haven't had an engine yet that I haven't been able to get running

Thanks for the offer Scott,
"Running" is about where it's at for me at the moment and "flyable" if I want to cruise around at a random throttle position where seems happy(ish), but it's useless for F3A work. I can find regulator and needle settings for idle, part throttle, and full throttle but can't find any settings where it happily transitions between them all or runs happily at them all.

I was just wondering about the hole location, and if that's where it's supposed to be then that's where it's supposed to be. I might just limit the throttle travel to just prior to where it starts leaning out and tune it with the main needle there to see if it makes a difference?

If I never find joy with it, I might send it your way and you can play with it on your stand if/when you have spare time. Maybe swap the throttle body?
Cheers
Brett

OK. See how you go. But if you need to limit throttle travel to tune it, somethings not right.

Well knock me down with a feather, when you google around looking for somebody to support a theory, you'll find it.
YS 160 / 170DZ

Instead of an o-ring, I was thinking about using a pipe cutter to "rill up" a tiny amount of metal on each side of the groove it forms . It'd only need a fraction of a thou to seal up the leakage.

Worth a try.

One thing to consider though. With a slight ridge, all the rotational friction would be on one small point and may wear the housing excessively.

Yes, although the end is supported by the o-ring and being rotational it should just wear a matching grove and form a really good seal.
Almost a very poor man's shaft micro labyrinth seal???

I just had a quick play with some 20mm dia ally scrap and it didn't take too much effort for it to form up a fairly blunt ridge on each side of the grove, see the tiny light gap in the image. I'm trying to close fractions of a thou so anything's got to be better than nothing?


Ridges next to shallow formed groove, raising end, creating light gap.

Yeah, should work.

The barrel may be hardened? Not sure.

Job done!!
Yes, there's some coating on it and I'm not sure if it's aluminium or steel, and under the pipe/tube cutter blade it felt like heavy anodising.
You can pull and hold a vacuum on the injector line now with the throttle at 100% and the pump line plugged. My DZ170 has a slow air leak under the same test.

I'll hold back on the bottle of Moet & Chandon Brut until I've had a few more successful trips to the flying field, but I just returned from the field this afternoon fingers crossed that the engine keeps running that good. Smooth idle at just over 2K and smooth run up to full throttle and back down. Fingers crossed (everything crossed) this has solved it !

That's good.

I'd say aluminium with hard anodising.