party pooper

YS 63 S Coolpower 30%
Was running fine out of Y.S. Repair for a bent crank. Before I get to the 3rd gallon of glow, I notice about 25% drop in power at the end of my flying day.
No more unlimited verticals. It falls out of verticle in about 15 seconds. Idle seems rough too and prone to stall at idle.
I adjust the vales , even though the power loss seemed to come on too fast to be the valves. I take it up again and the power loss and bad idle are still there.
The power loss came on over a period 4 flights. First two flight were fine. Seemed to be losing power on the 3rd flight . The 4th confirmed it.

I try factory initial settings on the carb. 2.5 turns out on the HS needle 1 turn out on idle.

The YS is blowing white smoak out the exahust more than usual.
I lean it out up to 1/2 a turn in from factory setting on the HS needle and no notable reduction of smoke, it's still blowing a lot of glow.
This YS just seems insensitive to 2.5 turns out or what should have been a too lean 2.0 turns out on the H.S.

Any thoughts on a correction ? I just seem to have a engine that dumps a high a ratio of fuel now, when the day before it was perfect.
Yes I put a new glow plug in. Yes I tried moving the Regulator Screw to either side of where Rich at YS left it. Regurlator adjustment was not the answer either.
No I did not toast the engine with lean flying. Most complaine that I fly the engine too rich.
I assume some O ring went that is allowing fuel to dump. Any ideas of what to try.

Party Pooper.

petec

My Feedback: (58)

If the engine is inverted are you getting fuel dripping out of the carb at idle or when it is not running? Do you filter your fuel? Is the fuel system holding pressure?

mjfrederick

Just a thought... what were the temperature differences between when it was running good and when it started losing power? Last weekend everyone at my field had to lean their engines on the top and bottom because we were all set up for cooler temps and it got pretty warm Saturday afternoon.

party pooper

Ptec I do not fly the YS inverted.


mjfrederick, I don' t check temperature except by finger touch, but I suspect this power loss is more than tuning for a temperature change. We're talking about a plane that went from unlimited vertical to coming out of vertical in 15 seconds and I did move HS needle to lean 1/2 a turn which is a lot from the standard 2.5 turns out. The idles I moved 1/4 of a turn to lean. Again a big move. There was no net change. Something is blocking the carbs ability to meter fuel and air.

I don't know the cause of that.

Would it be:

a particular O ring that is broken in a particular part of the engine - like the high speed needle O ring or another?
I adjusted the valves but used the same valve cover gasget. Do I need a dead nuts air tight seal on the valve cover, would this cause a pressure leak. I think that is possible, but remember, I'm getting too much fuel as it is. I would suspect the lack of pressure would starve the engine of fuel, but then again a YS also injects a lot of air. It's "Supercharged" and the lack of air would explain the rich running - I just wish someone knew if that valve cover gasket is critical to engine preformance?
Is it the regulator?
I just sense something going on other than a temperature change.

Party Pooper
'

petec

My Feedback: (58)

Yes the valve cover seal is important and has been the source of a lot issues.

I asked if the you had fuel dripping from the carb as that would certainly point to the regulator, which is what I suspect. That is also why I asked about filtering the fuel. The regulator plunger either sticking or being held open by some debris would cause your rich condition. A bad o-ring would more than likely cause more air or less fuel to be in the mixture.

So, do you filter the fuel? Is the fuel system holding pressure?

party pooper

Ptec,

" Yes the valve cover seal is important and has been the source of a lot issues. "

>> ok, I'll give the valve cover a new gasket tomorrow which should keep the full amount of compressed air going to the combustion chamber which will lean this motor out. I assume I have some of this pressure escaping out a gap in the used valve cover gasket which is making the YS 63 S too rich.


"I asked if the you had fuel dripping from the carb as that would certainly point to the regulator, which is what I suspect. That is also why I asked about filtering the fuel. The regulator plunger either sticking or being held open by some debris would cause your rich condition."


>>> funny you asked. The engine is not inverted. The carb is right side up looking at the sky, but I see droplets of glow jumping out of the carb air intake. So I imagine if the motor was inverted I would see drippling. In the past when my regulator went the carb would fill up and over flow with glow right on the set up bench at the field. That is not the case now but I am guessing the old and possibly leaking valve cover gasket is not allowing the air pressure to build up enough to over flow the carb. I do filter my fuel. Maybe the filter is old. Regardless, there is no air filter on this engine. So perhaps the carb ate some dirt and that dirt from the air intake reached the regulator.

>>> what is the procedure to opening the regulator on these YS 63 S. Do I just unscrew the ' adjusting screw' right out of the barrel or is that black plastic base on the regulator a pressure fit. If you were going to clean this regulator:
1. how would you take it apart the new S series regulators
2. what juice would you use to wash the regulator out
3. would you just count the turns it takes to remove the adjusting screw , ( if in fact that is the way to open the regulator ) for repair and when done repositon the adjusting screw on the regulator the same abount of turns it took to remove it?


So, do you filter the fuel? Is the fuel system holding pressure?

>>>>>It does not hold pressure.

Party Pooper
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petec

My Feedback: (58)

All good info, especially that it is not holding pressure. Once you get a new valve cover gasket on it we'll see if the fuel system will hold pressure. If it is still running rich then we'll move on to the regulator.

Sound reasonable?

tande

My Feedback: (48)

Hi guys....FWIW....."Holding Pressure" & "Generating Pressure" are two different animals....A leaking cover gasket will interfere with the ability to "Generate Pressure"....Probably not holding pressure because there is non to hold....As Petec said, get a new gasket & let us know...

Gulliver

To open the regulator on the 63 put fuel tubing over the nippples for protection and pry open with a screw driver. (per Richard @ YS service) Works great.

party pooper

Gulliver,


Did Rich say were to pry? is the location you wedge the screwdriver into the black plastic base or another location?


PartyPooper.

petec

My Feedback: (58)

You put the flat of the screwdriver between the nipples and pry against them which the reason for using the fuel tubing for protection.

party pooper

PTec

Ok, I started the YS 63 S. I was wrong with my earlier report on pressure. The engine does build pressure. In fact it held pressure for two days. I was able to hear the distincitve hiss when I removed the RED glow fuel line connected to the one way fuel pressure in line valve in the quite of my garage versus the noise at the field. Regardless, I replaced the valve cover gasket for good measure.
I just came back from the field and the this time I actually timed what use to be my unlimited verticals. It's upward momentum came to a stop in 7 seconds. Still no power and appears to be running rich.
This engine was always happy at HS 2.5 turns out and LS 1 turn out. I leave my YS's running rich since I prefer lube over ultimate power.

As to it being a bad regulator - well I have a second YS 63 S fresh back from YS Repair ( Rich). I swapped out the Regulator with one I know is good. No difference in power. It's still a dog.
The only difference between the Regulators is that the new one allows the engine to idle noticably better. The original Regulator would only hold an idle for 10 seconds before stalling every time without gunning it. The new Regualtor was superior in idle quality only.

Again I kept the HS setting between 2.5 turns and then moved it to 2.0 turns out. It does not care. The LS I just kept at 1 turn out to 3/4. I also double checked the valve settings since loose valves can be power robbers. The valves are set to factory specs after a 1 day cool down.

My guess, something like dirt is affecting the carb. The Regulator swap proved something only at idle - it did not correct a estimated 25% power loss. I would still like to get the original Regulator cleaned out. It does have idle issues. Any Tips would be appreciated and what liquid would clean it without hurting the seals.

As to what else can do. I dunno - unscrew the HS and LW Carb adjusting screws all the way out and shot Carb Spray down both needle holes with automotive carb spray or is that stuff too harsh? Would a blast of air from my compressor be better or would that just jam the dirt in even further? I'm hoping this is just a dirty carb issue, but I could use some Regulator and Carb cleaning advice. I do have a Regulator rebuild gastket kit and carb in stock.

The only other thing I noticed is when I turned the engine by hand after it was dead COLD for 2 days. The compression stroke seemed wimpy. I did not seem to notice the same strain on my hand as the piston moved to Top Dead Center on the compression stroke. So bad rings ? In my opinion , rings are a slow death and this power loss came on me withing one day - 4 flights. Maybe dirt on a Valve Seat and if so, how do I clean that? After the engine was on the field today after running , the compression seemed to come back to some degree, but i seem to remember more compression resistance. Keep in mind, this engine's life is at 6 gallons of 30%. My flying habits are more of a pylon racer. I'm usually floored, but I'm floored with plenty of smoke. I just keep the inital settings of 2.5 turns out HS and 1 turn out Idle.
Can a YS go though rings in 6 gallons?

So I need Carb and Regulator cleaning steps and any other advise on steps I can take. Can I compresion test these engines?

Party Pooper.

petec

My Feedback: (58)

Do not use carb cleaner, it would damage the seals, use raw fuel or isopropyl with raw fuel being preferred for cleaning as then you get the added benefit of some lubrication on reassemly of parts.

The LS needle is just an airbleed on the throttle butterfly and really has no effect other than at idle.

Something you posted earlier along with your last post has me suspicious, you said you are down on compression and earlier you stated you don't have an airfliter on this engine. I wonder if you ingested something and scratched the liner. If you are always at WOT when flying it could have exacerbated the the problem. It's hard to say what kind of wear would see on the ring in 6 gallons of WOT flying. In dusty conditions that would certainly wear the ring and liner seal.

At any rate, if the valves are not sealing properly you will hear them hissing as you come up on the compression stroke. To clean them you would need to pull the head and lap them. Once you have the head off you would also know if the liner was scratched.

party pooper

Petec

I think I'll send this engine back to Rich at YS. As to the compression, has me worried too and I beleive the ' liner' on the 63-S is not removable. It's part of the whole cyclinder head. YS claims this aids in cooling efficiency. I'm sure it does, but to me this means $125 for a new jug that will probably be gone in another 6 gallons. I'm not that trilled with this engineering feat since the repair - before labor- is half the price of a new YS 63. If you think about it. For a 3D flyer who does not get a lot of air flow , it's a good design. Most of these 3D fliers never take their planes to the speed and air flow I reach. Now your would think on a a plane with ( no air blocking cowl) my WOT and 60 mph flight would supply all the cooling air flow the engine needs. But this is of little good if the engine can't keep dirty air out of that cylinder liner. Too bad this industry or a secondary vendor does not come up with some sort of filter. As to the fuel filtering, I filter the fuel twice as it comes out of the gallon. I have no filter going to the engine. I assumed the duel filtering to the tank would do it. Any thoughts?

I hope rich can hone the cylinder liner before replacement, but I don't think so. It was a great engine and I'm sure it's life expendency would be far more than 6 gallons if used strickly for 3-D but WOT type flying even if you run this engine rich, which I always did, to compensate for my ill mannered WOT type of flying didn't save it. I've always been cursed with a lead foot since I was a teenager. The lead foot seems to follow me as I approach 60. I realize it's not the best kind of flying and requires no skill, but I can't help myself. I'll have to find a engine with a replaceable cylinder bore liner. I wonder if Saito has a replacable liner that is cheaper to fix than a brand new $125 jug. That may be the better move for me in the future if Saito can replace a liner for $30.

Is there a way to filter the air on a YS. I remember Central Hobbies having a wire mesh cap that would go over the Carb - but I don't recall if it fit on the 63.

As to the Regulator, any tips on cleaning it?

Thanks for your help

Party Pooper

petec

My Feedback: (58)

It's not so much the airflow as it is RPM at WOT that will accelerate the wear of the ring/liner. If the liner is not scored a new ring may be the simple fix but until you pull it apart and inspect it you won't know.

I don't know of a ready made air filter for the 63. The ones central sold were for the 1.20 and up engines if memory serves me correctly.

If you decide to pop the regulator apart to clean it make sure you do so in a clean environment. I use a pan with a strainer filled with raw fuel so I can clean the parts and not have them sit in any debris that may be cleaned out.

If you are contemplating sending the engine back to Richard though you might just have him do the regulator as well since he will have all the parts there in the event it needs anything.

Jetdesign

My Feedback: (8)

I have been taught to ALWAYS run a fuel filter before a pump/regulator, YS or not. I have a 120AX with a perry pump/regulator that has a filter before, and I have an inline filter before the regulator on my YS.

petec

My Feedback: (58)

I run a filter on all my engines, pumped or not. Very cheap insurance.

I missed that part of his post Joe, thanks for pointing it out. Yes you want to always run a filter on a YS as any crap that might make it to the tank would be best caught before it causes grief with the regulator.

nonstoprc

My Feedback: (90)

Could it be the case that dirty/sand got inside the engine during the initial "crash" and not cleaned up? It could cause quick loss of compression.

party pooper

Petec, GaRCfield, Nonstoprc.

1st Nonstoprc - This engine was crashed before and I assume some dirt could have gone down the carb. I sent it back to Rich for a new crank shaft a while back. My guess, he got all the dirt out from the previous crash since he had to go that deep into the engine. A friend of mine use to fly with Rich years ago even though we are both live here in CT and Rich is now in Nevada(?). In his opinion, you won't find anyone better than Rich. Regardless your point is good. I'm sure there are a lot of guys who put new bearings in and forget about that chuck of dirt wedged in the carb venturi when they go to start it up.

2nd GaRCfield, I'm with you on the filter. There is a big Saito guy up on my field who works in the Local Hobby Store and does the repairs. He is not fond of filters going right before the engine. He just puts the filter between the fill plug and the tank, but not in front of the carb of the Saito's or in our case, the regulator. Next time I see him I will ask him what he fears. Regardless, I reached in the drawer and put a YS Filter right before my regulator and tomorrow I will replace the filter on my fuel jug.

Last but not least, Petec. As to the WOT RPM and possible compression loss. Well I cranked both my YS 63's by hand. The troubled one I would say has less resistince going into TDC and less snap when I get the prop just past TDC. Is it a lot less? Tough to tell by just using my hand to turn over both engines slowly , but I would say the toubled one feels to have 20% less resistance before TDC and 20% less snap past TDC. Let's hope the $125 liner is good and just the cheap ring is gone. I thought the rich setting would buy me more time on wear, but this may be proof that these engines, probably any engine, is really suited for only brief busts of high RPM versus my long ovals around the park at WOT. Tomorrow I will attempt throttle control on my other YS 63 S 4 stoke. I learned my lesson. I'll buy some junky two stroke for my WOT needs if this YS went though it's ring in 3 gallons or worse, the $115 jug with no removable liner. That kind of thrill is not worth the price. I admit, it's abusive on my part, but I thought a rich running engine would last longer even with my abuse. I'll see what Rich says and hope it's just dirt in the carb. and a touch in the regulator. It will be a costly but worth will experiment for me as to rings in a glow versus rings in a two stroke gas engine. I have an old Kault 22 which was really a Zenoah 23 marketed under the Kault name. Being mounted on a rather heavy scratch build foam wing plane, I always ran the relatively underpowered , for the plane, at WOT for years, and the plane was bought 5th hand. Although Zenoahs are also used on back pack leaf blowers at WOT, a gas 2 stroke may be better at WOT for fliers like myself.


Party Pooper.

petec

My Feedback: (58)

Let us know what the verdict was from Richard.

David Bathe

I've developed the exact same problem on a 1.40... ran perfectly for years and years and then, all of a sudden top end bogs down once the engine heats up and reduces power. It's been fully served twice over it's life time and been examplory... until this.
Let me tell you it isn't/wasn't dirt in the carb.
Full strip down rebuild, changed the rings (piston and O's) diaphram, valves etc....didn't help.
I'm going to change the bearing now (even though they aren't that old and feel perfect)... it's the only thing that isn't brand new.
Funny thing is... that was the first thing somebody mentioned when I first noticed the problem[]

boysnake

Check that the push rod cover o-rings are seated propery. On the 63 the push rods covers don't stand perpendicular to the crankcase/cyl head assy resp. If this is the problem glue two bushings onto each push rod cover to prevent the o-rings from popping out.

Guttorm

party pooper

Guttorm ,

I have the same issue as previous poster "David" especially when he said " after the engine warms up the high end power goes away." The Engine is with Rich now at the YS repair shop. I will post when I get it back as to what he found - but that could be 4 weeks from now.

I have a YS 63 S engine diagram folded out in front of me. I've spotted your item # 42 Push Rod Cover O rings . I see 4 of them. Two at the bottom and two at the top of the push rod tubes or # item 41 " the push rod Covers" which are just the two metal tubes that shroud the Push Rods or the two metal tubes we snap the 'Regulator' on to in the front of the engine.

Hard to tell from a diagram and no broken down engine in front of me , but it seems to me that these 4 'O' rings have tiny seats machined in them, at the extreme end of the those two Push Rod Covers. To word it another way, the two tubes of the Push Rod Covers seem to be machined at the end of the tubes to seat the O rings and hold them in place. Then the two tubes and the O rings get pressed between the Crank Case and the Cylinder Head where everything is held in place. I'm guessing the power loss David and I experence , after the engine is hot, is from expansion and these O ring seats opening up ?

I realize those reading this post don't have their engine parts break down diagram in front of them that comes in the box when you get the engine, but clearly we can all visualize the two metal tubes in the front of the engine that cover the Push Rods for the valves and these same Push Rod Covers are where our REgulator is snapped on to and this assembly being pressed together by the four screws that hold the cylinder head to the Chrankcase.


I am trying to figure out where you say to make the home made bushings to hold these 4 O rings in place. Is there that much room to fit a bushing? Do you want a bushing for all 4 O rings?

Also , if these O rings are floating around somehat loose in their ' seats' - I assume you want a bushing to be made to remover the slack? I assume you are using metal bushing? Are these loose O rings causing a pressure leak and the reason David and I lose power at the high RPM when these engines heat up and those seat's expand?

Party Pooper

boysnake

Yes, I suspect this may be your problem. The o-rings are held in place by the pushrod covers (tapered at the ends) . On the 63 the covers don't stand perpendicular on the o-rings hence they sometimes pop out.

- Make of find 4 suitable aluminum bushings with outer dia just covering the o-rings. I drillet out the threads of some blind nuts (see picture)
- Slip two bushings on each pushrod cover
- Properly clean the o-rings and their seats (get new o-rings to be safe)
- Assemble the engine and make sure the covers are properly centered and seated in the o-rings
- Press one bushing against each o-ring and secure with drop of ca.
- Enjoy

Guttorm

party pooper

BoySnake

I appreciate the pictures of the 4 O ring bushings you made from blind nuts.
Just to better understand the situation. These 4 O rings at the end of the push rod covers seem to be pushed or slid into their seats with really no pressure to hold them in place.
It seems just the friction of the tight O ring is all that is holding these O rings in place at the ends of each push rod cover tube.
Not that I have any clue as to my power loss, but I'm now trying to figure out why these O rings would affect my power loss at the top end of the motor?
So now I wonder what YS ever intened for these O rings . They appeart to do noting more than to keep dirt out and perhaps any leakage of low pressure glow fuel.
I'm getting the impression these O rings may be holding back the full high pressure that a YS developes and if I'm losing that pressure that is causing my 25% power loss at the high end.
Is this rational correct. Have you put your home made blind nut bushing on and discoverd an instant regain of power? Could the pressure be leaking out past these 4 O rings?


PartyPooper