Hello Troy - I've had great success with my 110 over the past couple years, but recently I have been having problems maintaining idle and transitioning throttle up prior to take off. I'm running a 15x8 APC prop, Wildcat YS 20/20 fuel, OS F glow plug with the brass ring, the engine is mounted inverted, I have about 12 gallons through it, valve clearances within spec, and it's been about 88 degrees outside. The problem seemed to worsen when the weather got hot and I started on a new gallon of fuel. I've gone through another gallon of fuel since then and still have the same problem, so I don't think that is the issue. Also, since the problem got worse I've been flying without the cowl so I could adjust the low and high speed needle valves as well as the diaphram screw, so proper cooling should not be an issue.

So here's where I'm at now: I tacked my high speed RPM at about 8600 and low speed RPM at 2600 (any lower and it dies). I can maintain idle at that RPM for about one minute, afterwhich it will wind down and die. High end runs very smoothly, but the engine often dies when transitioning up from idle with the glow driver off; at around 1/4 throttle, the engine will begin hesitating as if it is loaded up, and then it will either clear itself out and open up, or die and spin freely as if there is a loss of compression. With the glow driver on, the transition is smooth and the engine will not die. The diaphram screw sits slightly above the housing, which has always been the case on this engine. A small amount of fuel drips out of the carb as I try to start the engine. Once airborne, the engine runs well so these problems are only seen on the ground as I try to run up my engine, taxi out, and begin my take-off.

I've been following the tunning instructions and adjusting the needle valves and diaphram screw, but I can't seem to dial it in. I have a competion quickly approaching (Sept 22nd) so I'm hoping to get the engine running smoothly ASAP. Thanks for your help!

Steve Insalaco
Arlington, VA

Not speaking for Troy but I'd be wondering how old the plug is. Have you tried a new one? Sounds like it's rich on the bottom end or the glow plug is at the end of it's life span.

if you go down just a little I have a post 120 fz leans dies leaks fuel out the carb. thier is some very good info that mr troy has posted and some tank/regulator carburetor explanations. after reading you may have a direction. I am no pro so no advise. lol. hope it helps.

arf

I would think glow plug as well. If it works with glow on and not with it off...then the plug is likely worn out/defective.....

Also it could just be rich on the low end. Rich will often be solved by leaving glow plug heat on. This is one way to tell is a low end or transition problem is rich or lean.

A little rich on the low end could be the culprit.


Running it on the 15-8 with only 20/20 fuel at 8600 you are taxing the engine pretty good considering the higher temps you are running at. I would say go to a slightly smaller prop say 14-9 it will turn that easier. Or go up in nitro to help the 15-8 turn easier.

You want to run about 9400-9500 on the 110 you can venture to the low 9000's but I personally would not run it below 9000...This could be your heating issue. Some people think that if they take the cowl off it solves heating issues.... However you would be surprised how the cowl when flying on many models not all...would do a better job of directing air flow at higher velocity to the right spot to cool the engine. Sometimes the cowling issues will get way worse with removing the cowling. This also makes your model tail heavy....I don't know for sure as you didn't mention which model and I have no idea on how your cowling is cut to allow air in...


On my Pattern model the engine and exhaust system is fully enclosed. I actually have ducting inside to direct the air flow. If you remove that cowling the cooling issues get way worse.

At 88degs F where you are its not really a problem with cooling. You are getting hot if you are getting hot because of the higher load you are putting on the engine. Go to a lighter load and it will help you get the settings correct.


First off change the plug and see if it comes back in line. If not start by leaning the low end a little The idle adjustment screw is an air bleed screw. OUT or CCW is LEAN...


If you are more than about 2.5-3 turns out from full closed on the air bleed screw then adjust the regulator screw Leaner by about 1/4 turn increments. IN or CW on the regulator screw is LEAN.


Troy Newman
Team YS

Thanks for the quick responses! I have tried replacing the plug, but will try another one just to be sure. How many gallons of fuel should I expect a plug to last, assuming the engine is tunned properly? I'll also reduce the size of the prop to achieve a top end RPM over 9k, and will tune as you mention. I'll let you know how it goes.
thanks again,
Steve

It all depends sometimes they loast a long time 20 gallons and sometimes they last 3-4 gallons.

If you fly on grass fields the plugs will go quicker from the dirt and crap that gets sucked up into the carb while running down the runway and just being started up in the grass areas.

here is a website that has details on setting the mixture and other ideas to help

http://www.probuild-uk.co.uk/factsheets/ys_engines.php


Troy newman
Team YS

Hey Troy - Just wanted to let you know that I got my engine running very reliably now. I put in a new plug and put on a 14x10 prop, which I know isn't really any less of a load than a 15x8, but it was the only other prop I had on hand. In the end I had to significantly lean the low speed mixture and slightly lean the diagphram screw. The engine now idles and transitions very well, but I'm still not able to get more than 9k RPM, so I'm going to try to prop down to a 14x8 or 14x9. The engine is in a CA Models Widebody 60 and I'm able to do knife edge loops and vertical snaps so I don't really need any more power, but will prop down to keep the engine running cooler. Thanks for the help!
Steve

Its the 20/20 fuel that is keeping the rpm lower. Go to the 30% and you will be surprised, If you want to stay with the Wildcat...they make the Curtis Youngblood blend use that.

Or get some 30% Cool Power Heli Performance. You will be amazed by the increase in performance and the way the engines run. Its really good. My understanding is the Curtis blend is very similar.


Troy Newman
Team YS

I am using the Curtis Youngblood 30% heli blend in my YS 1.10 with an APC 15x10 on a KMP Critical Mass.

As compared to the old 20/20 blend, this 30% has given me that last little bit I needed to be consistently competitive in the Warbird Silver class in our area. Keep in mind, that big round nose on the Sea Fury is being pulled with enough power to make it competitive with the same powerplant in the pointy nosed P-51's that are so prevalent.

I am not peaking this engine to the nth degree to get the max power out of it. And I have not had to move the needle more than 1/4 turn for the last 10 months.

I think it's safe to guess that the Curtis Youngblood 30% heli blend is safe to run.

http://www.rcuvideos.com/item/LB393Z7TWD25JLHY