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I must take my hat off to all of you. The vent line had come off while I was tightening fuel filters. Corrected that and placed clamps on all connections. I plan to fly this weekend. The only other thing I noticed is that eventhough it starts easy the first time, subsequent starts always runs backwards, speeds up, slows down and then just before it quits, it jumps back in the right direction and runs fine. It idles somewaht OK at around 2000 rpms after I made two 1/8 turns to the lean side of the low end. It could still be a little rich but I think I need to get some flights on the engine. I read somewhere not to have extended runs on the bench.
One other thing; This engine was turning a 14/7 three blade Master Airscrew above 9000 rpms at the top of the high end adjustment.
I'm using a 15/10 APC now at around 6000 rpms. Does this sound right are am I too afraid to lean it out all the way (before backing off a couple of hundred rpms?

Whats you evaluation of the above?

Thank you all!
Carl

You do not want to be around 6000 rpm. Try to stay above 9000 rpm. Otherwise, you will lug and overheat the engine.

vent line came of my saito 80 in my p-47 engine ran like ****! used a tie wrap to fix now its fine

Your engine is too new and tight for the 15x10 just yet.

Get some run time on it with a 15x8 and after it loosens up go ahead and up the prop size.

I run the APC 15x10 on this engine in my TF F4U , a KMP Critical Mass, and a Skyshark ME109G6. They all run strong and fast.

The Critical Mass may actually need more prop. I'm still experimenting on that one.

Glad to hear you found the disconnected tubing. I always use high-quality (Prather) tubing on YS's to make sure that connections stay tight and leak-free.

I agree that a 15x10 is too much prop right now. Run and fly with a 15x8 APC until the engine breaks in and gives you at least 9500 RPM. This shouldn't take more than a gallon or so. Run only 20/20 or 30% heli- I prefer the heli fuel. It is fine to fly during break-in. Once the engine is broken in you can load it up with more prop. I run 13.8x10 4-blade props on my P-61 and they turn around 8900 RPM on the ground. Performance is excellent with these props but I personally wouldn't put any more load on a 110 than this.

YS's don't like to be run very rich, for break-in flying I find the peak and then back off until RPMs just begin to drop off. After a few flights I tune pretty much to peak and keep it there. This has worked well for me.

It sounds like you are starting your engine by hand. If you have a good one this is possible, but it is a whole lot easier to use a starter. There's a lot going on inside a YS to make it work and sometimes it takes spinning over at a good clip to get it primed and ready to fire off.

Walt

The 15/10 was an error. It's a 15/8. I might put the 14/7 3 blade back on or whatever will get me to 9000.
Thanks Richard.
By the way I did find various muffling options from Central Hobbies. I'll be ordering one today.

My mistake. It is a 15/8. Yes it does start easy by hand. I think I'll go back to the 14/7-3 blade.
Thanks

By the way Walt, I went back and tie clamped everything.
Carl.

Carl you should be getting over 9000 RPM with the 15x8 right out of the box. Lean it out until you just hear it sag back from being too lean, come back a 1/4 turn or so to get it to the rich side of peak and then see what the tach says. If you are not at least very close then something is still wrong.

Walt

Hey Walt. Yes I was afrtaid to turn the needle valve in any more. In the mean time I put the 14/7-3blade back on. Do you think the 15/8 single blade is a better choice at this point?
Carl.

Carl your engine should spin the heck out of a 15x8, I get 9800 RPM+ on 30% heli with that prop. I would put the 15x8 on it and get the engine broken in and running right, then try multi-blades.

You really need to find the peak in order to set the engine correctly. 1-1/2 turns out should be in the ball park. Start with it a bit richer than this if you like and then slowly turn the needle in. As you lean it out you will know when you are close to peak, it will be like hitting the afterburner. If you go a little too far you will hear it sag back. As soon as you hear this immediately richen it back up to where you want it. If it won't turn the 15x8 hard after doing this then something is still wrong.

Walt

Carl, I have several of these engines in various warbirds... getting them tuned right can be a bit of a challenge, but oh so worth it. You absolutely have to get these motors into the 9000+ RPM range for them to truly perform IMHO.

One thing that hasn't been mentioned... you may want to double-check your pump (midrange) setting. The top of the big brass screw should be flush with the housing, but it may need some tweaking even from the factory (one of mine was way off right from the factory). My experience is that getting that right really makes a big difference with the overall engine performance, even on the high end. And, a way-too-lean setting can cause the surging you mentioned.

One way to check to see if you're in the ballpark is this: start engine and let it warm up, grab a tach and go to mid throttle.... the tach should come up to around 4000-5000 rpm and stay pretty much put. If it sags down with lots of smoke, you're too rich. If it speeds up or goes up then down (surges) you're probably too lean. Small adjustments on this one too.... just 1/16 turns or so until you get it steady.

As far as high-speed needle tuning, Walt described it perfectly but a word of warning: don't let these engines run lean for very long. With the "supercharging" they do, they will backfire and throw a prop quite easily (don't ask me how I know []) Be quick on the needle once you hear it sag.

For reference, mine turns an APC 14x11 two-blade at around 9400 RPM static on Coolpower 30% heli fuel.