robert

Thanks Alejandro and Keith, I'll give that method a try next time. Good to know it isn't a problem with the motor.

cdodom

Right now I am running the YS 175CDI and I am having trouble with the throttle barrel. It seems that when the engine gets to running and gets to operating temp the throttle barrel starts to stick at Idle.

Has anyone had this type of issue before and what you may have done to fix the problem.

Any suggestions are greatly appreciated.

Thank you,
Chris Odom

tuny

Hello Chris! I had that problem on one of my 170s never on the 175s, I fix it by polishing the barrel, also check that the screws for the back plate are not over tight, therefore twisting it.

best regards

TUNY

Dave Harmon

Chris....sometimes the small tab that is on the right side of the barrell will be installed crooked.
This should fit square to the groove in the barrell....also the surface of the tab is slightly oval shaped and can cause a bit of drag...you can turn the tab over to see which way is the smoothest.
When you remove the barrell...take it out of the housing on the opposite side of the throttle arm....there is an O ring that will be sliced if yo drag it across the intake opening....put back in the same way.
The idle stop screw can also stick up the barrell....unscrew it far enough so the barrell does not come in contact with it when at full idle and at idle cutoff if you kill the engine this way.

cdodom

I checked that and all is perfect. I think that the barrel could be warped.

grcourtney

My Feedback: (1)

The Barrel is not warped .. pull the barrel and look for a rub you may or may not find one. then get some 2000 sand paper roll it and sand the inside of the carb where the barrell fits.( lightly) clean the barrel, that red stuff you see on it will build up and cause sticking also.. This happens when it gets as hot as its been. Also look in the groove where the throttle stop screw goes some times the threads from the screw will dig into the barrel causing it to stick on the low idle.


or give me a call u got my number

G

cdodom

Thanks for the tip Gary! in the mean time my dad had a spare 160dz so we took the entire carborator off the engine and installed it on the 175. I flew 8 times today and the engine never missed a beat.

Thank you,

Chris Odom

MrShoes

My Feedback: (15)

Resurrecting an old thread, but did YS ever resolve the heat-related pump issues? Is the DZ series still having issues? Wondering since it appears YS is discontinuing some of the FZ (fuel pressure system) engines in favor of the DZ. I have numerous YS engines and never had a problem with any of them, but leery of the DZ series. Thanks

riot3d

The 140 DZ was definitely on the temperamental side, but it's been fixed since the 160 days. The 170 & the 175 has been pretty much foolproof for me, & I will be flight testing the 185 next week, weather permits. I have been staying away from the cdi version in general, not because it's not a good combo, but I have more than enough power for both the P & F sequence so don't need additional weight.

Adrian

sleeping

I've found the CDI's to be a little more fuel efficient & will use 20%N for practice & 25 for comp. For US guys, Brian Herbert is developing a slightly larger grill for cooling that - he says - is getting about a 100RPM extra. This on the 185 on his new Bipe the Alferma. Really nice model - worth a look.

cheers
DA

MrShoes

My Feedback: (15)

So pump must still be kept cool to prevent fuel delivery problems? What about pump longevity of the newer engines (DZ175 and newer)? Anyone have extensive experience with the DZ70, as far as, pump reliability/longevity? Thanks

sleeping

I can only speak for the 63 (which doesn't have an active pump) DZ160 & the 170 cdi. The 160 would have 500 + flights & has been rebuilt 3 times now replacing P & L, main bearings, always o-rings on throttle body to head and needle; I cannot remember replacing any elements of the pump but it would have been inspected and if the Dia looked at all suspect it would have been replaced. The 170 is still pretty new but doesn't miss. I dare not start a 'fuel war' but I stick with Cool Power. Home Brews & Klotz I've always found trouble. Why not home brews? It was actually Curtis who answered this years back (he runs Klotz...but Helis are another game). He said the N & oil can take up to 2 weeks to blend. And of course moisture. Although I've not heard of this problem, of course, it makes sense. With Helis we literally put our finger on the backplate and if we cannot hold it there things are too hot. I'll try the same next time with a plank but really, if you have concerns look through the cool power catalogue & you will find varying oil %'s at same N. And shape a shroud inside your cowl towards the pump.
The biggest problem is not keeping the tappets measured across the board.
good luck
Da

apereira

Yes, the cooling issues have been gone for a while, unless the engine does not have any air coming to the pump fins. Longevity on the 175 is better than previous, but not enough time on the 185 to tell, but it sure looks superior to the 175, and this engines are reliable as they can get, as long as there's good tuning , good fuel, and the pump does not stay with old fuel for a long time.

Regards

Alejandro P.

MrShoes

My Feedback: (15)

Thanks for the answers. In Texas, the ambient air temperatures can get past 100F, so I was concerned about the pump heat issues. So no longer any need to wait ~ 30 minutes between flights or fans for engine to cool down? No engine pump overheating during idling? Thanks

apereira

On our field the temperature is about 95F, and never had any issues, but the 175 and 185 runs hotter than the 170, I always run my engines on the rich side and never had that problem, even in Muncie, it was well over 100F and had no problems, I only run Cool Power 30% Heli, maybe with 20% Nitro it will run hotter, I remember having to wait for the 170 to cool off or the engine will not start, but it was a long time ago, and never had the issue again.

Regards

Alejandro P.

apereira

One thing I forgot, There was a version of the pump on the 170 which has or had a copper (I think is copper) piston liner on the pump, I think this is the pump which used to overheat, since that pump which I think it changed with the Hyper version of the 170 when they went back to the original aluminum liner which is simply the pump body and the steel piston the overheat problems went away, anyway, the piston is larger on the 175, but so much you could almost fit the first 170 piston on the 175 one, but the body remains the same, so there's less material on the pump and that also helps keeping the temperature down and cool quicker, I have not taken apart the pump on the 185 and do not plan to do it anytime soon, but we will see if it has differences, I currently have two versions of the 170 pump, and one on 175, all different, even if they look the same, all from engines I use.

Hope this helps

Regards

Alejandro P.

MrShoes

My Feedback: (15)

Alejandro, thanks for all the in-depth information. I bought my first DZ engine (DZ70) today.

apereira

Very nice little beast is that engine, amazing how they can make a DZ so small, enjoy it!!

drac1

My Feedback: (4)

I have 108 flights on my 185cdi in temperatures up to 38 degrees celsius (100 deg. F). No waiting between flights, engine starts immediately and idles perfectly.

I mix my own fuel. 30% nitro and 9% Coolpower MV oil.

I never had any issues with my 170cdi's and 175cdi's either.

sleeping

A few Aussies!! On the thread! That's nice. I don't envy 100 deg at the field guys; 86 is absolute limit for practice. And most fields are no more than 1000ft above sea level. Only one magnet I know of got thrown last year and if we have over-heating problems, it's probably time for new bearings.

Aper made a really good point earlier about nitro %; in that if you reduce it from say 30 to 20% the engine is going to run really hot unless you prop down.

Just on cavitation, of the fuel within the pump? I know Yamada has updated some seals as noted but for fuel to vaporise from ️tank temperature - I find a stretch. Again as others' have pondered there might be leaks in the line or even the tank perhaps. Even a dirty clunk.
It's interesting to watch one of our best pilots with the 185 in the Naruke Acuracy (they can't spell!) Bi-plane. It just doesn't stop pulling. But to be fair there is maintenance required. I know that the later 175's & 185's can go very low on oil with the right parts. But is there any benefit? Just curious on that

all the best
Da

drac1

My Feedback: (4)

All cdi engines are suitable for low oil, including the 170cdi.

I think the reason behind the low oil content is to reduce the smoke trail. Many judges watch the smoke trail to look for mistakes. If the smoke trail is less noticeable, then it is harder to use it to pick up mistakes.

Benefits - Cheaper fuel and way less oil to wipe off after flying. After 6 flights with a cdi on 10% oil, there is less oil underneath than 1 flight with a glow on 20% oil.

sleeping

You're worried about cheaper fuel when approx $7,000 in the air ?!

drac1

My Feedback: (4)

I didn't say I am worried about it. You asked are there any benefits and cheaper fuel is a benefit.

As far as I'm concerned, the cost of fuel is what it is, but to some people you would think it is a life and death situation.

I don't really care what it costs, but if I can save a few dollars on fuel, it can be better spent elsewhere.

The biggest benefit for me is that I can run a smaller tank. I saved 15 grams by fitting a smaller tank and the take off weight is also reduced. I can't see the point in dragging 250ml of fuel around the sky on a joy ride.

bjr_93tz

Best tip I ever read here was (and I forgot who wrote it) was that if you need to add weight to the front of your plane for CG purposes but couldn't shift your gear around and were struggling with the 5kg, an appropriately sized hopper tank at the firewall was the way to go.

Gets the CG where you need it and you drain it out for the weight-in

That's right up there with your helper placing himself between the plane and the noise meter or putting a tiny rock under a main wheel back in the day when the plane needed to stay stationary after the helper released it..

drac1

My Feedback: (4)

I never thought of that one Brett, but a good one to remember.
I've had the opposite lately. Trying to reduce weight on the nose. Maybe a header tank behind the CG. Lol.