Looking for an explaination of what may have happened. I have a brand new YS FZ110. This is my first ever 4 stroke. Yesterday I took it to the field to break it in. I am turning a 14 - 8 APC prop. A 3 inch spinner with an aluminum back plate and plastic cone. Everything was tight with lock nut in place. High speed needle was set at 1 1/2 turns out to start the motor and then opened another 1/4 turn to richen up further once the motor started. I am using Magnum Fuels fuel that is 20% Nitro.

I don't have a safe way to bench mount this motor to do the break in, so I mounted to the plane and went to the field. This allowed me to use their plane stands and also have some more experienced people around in case I had questions. Everything started and ran REALLY well. I can't believe how strong this engine is just in the break in stage. Anyways, the instructions say to run it for 20 minutes. I was at 19 minutes and I was talking to one of the more experienced guys at the field when the motor ran out of fuel. You could hear the motor lean out quickly. I chopped the throttle to kill the engine. When I did this you heard a kind of pop. Everything seemed ok, I refueled and went to start up again. Using my starter something seemed to "grind" upon trying to start.

Upon investigation it seems that the knurled drive washer on the 110 and the knurled backplate of the spinner have spun. Both are worn down pretty good. Everything was tight upon start up including the lock nut. When we dissassembled everything the lock nuts were still locked tight. It seems that the drive washer may have not been seated fully onto the drive washer retainer and during the breakin, everything seated and caused just enough room for everything to slip. The guy I was with said he thought the engine backfired when I chopped the throttle. This is when the slip happened.

Question is, is there something I did wrong here? Will YS warranty the drive washer or am I going to have to suck it up and buy a new part and a new spinner?

Running the engine out of fuel is running it Lean!
You should never run any engine out of fuel. It can result in damage, as the mixture will go lean. On 4 strokes because they have so much torque they can spit the prop and spinner. In your case you are very lucky. Instead of the prop coming off and flying at you or someone else, the double jam nut protected you. It did not however protect the engines thrust washer.

The engine backfired and the prop slipped. This is common of the damage caused by a lean run. Hopefully there is not any more damage internally to the engine.

A 20 min run time is usually recommended before you try to fly the engine. 20mins of run time doesn't mean that it will run for 20mins on a single tank of fuel/ This would always depend on how large of tank you have.

A good practice is to run the engine for about 5-8 mins at time then let it cool completely before you start it again. I don't always do this personally but its a standard practice for breaking in an engine.

Looking at the picture I think that the prop was probably slipping the whole time and the double-nut kept it from coming off. YS prop nuts have to be seriously tight to keep this from happening, much tighter than any other engine I have used.

A trick that I picked up from Dave a while back is to cut a disk from fine emory paper and put it between the drive washer and the spinner backplate with the rough side toward the backplate. This helps a whole lot- but you still have to tighen the x;!k!! out of the nut. Troy do you have a better trick than this?

Walt

Walt,

When having a knurled metal back plate I like to use a nylon washer (found at OSH) in between the back plate and the thrust washer. I tighten the nuts as you do. I also check the nuts for tightness every few flights. Since I started doing this my thrust washers have really held up.


SooprDink,
I would check with Richard at YS parts and service. His number is (775) 267-9252.

Jimmy Skids

Called Richard and he echoed what all of you have said. He is sending me a new drive washer. This is my first YS engine and I must say, I am very impressed with the power of the engine and I am also very impressed with the customer support offered by YS and Richard in particular. Thank you all, I have a few good lessons from this experience!

Shaun

One more thing you might try that I learned after a couple of new drive washers and spinner backplates...

The emory paper trick didn't work at all for me, some great smoke from the drive washer/backplate area when I started the 110 and another ruined backplate and drive washer but that was it. What I do is start the engine, run it for a couple of minutes without getting too much RPM, then shut it down and tighten the prop nuts again. I do this three times with new stuff gradually increasing the RPM each run to full throttle on the last one, and then check after each of the first three flights. I'll generally get a little more tightening each time I do check them and I keep doing it until the thing is no longer slightly loose when I check it. Then I just check it every so often once it's tight.

It's just kind of a problem when you've got an aluminum drive washer riding on an aluminum spinner backplate and the pre-cut grooves in the backplate and the drive washer don't match each other, swinging a 16x6 APC prop in the mid 9,000 RPM range, but the power output of these little engines is just amazing. As you do these run-ins the grooves will actually get a little filled with aluminum on the drive washer and a slight wear pattern in the spinner backplate, this is what cause the looseness. Do whatever you can to avoid a backfire, but if it does happen, make sure you check the prop bolts immediately. It's a bit of a hassle and the drive washer won't look new anymore, but I've not had prop slipping problems since I started using this method.

Just my two cents worth.

I use the following procedure to tighten the prop nut and the lock nut, with a good wrench (about 6 inch long).

1. tighten the prop nut first, with left hand holding the prop blade and right the wrench, until the wrench can not move further
2. repeat the above step for the lock nut

Never had a problem.

I exclusively use TruTune's YS prop adaptors (prop nut and lock nut).

Jimmy,

I'm not familiar with the abbreviation "OSH". What type of nylon washer are you using? Is it a thin washer with a diameter the size of the props thrust washer?

A rough 60-100 grit Emory cloth type sand paper will work. I have also heard of some folks using a thin piece of Leather. I have never done the Leather thing.

The prop will only slip if you run it lean and it backfires.

Troy Newman

Troy,

I have been reading in other posts about lubricating the cam before the break in process. The instructions that came with the motor said nothing of this process therefore I neglected to do this. I have run my first tank of fuel already. Have you seen much damage from this type of first run scenario. I guess I am really concerned that I may have shortened the life of my brand new engine and if this is a critical step then why is it not in the manual?

Putting oil on the cam before the first run is not required. I just personally do it. Just like any model engine on the market. When assembled at the factory they get some oil inside, but my question to you is how old is your engine, or how long has it been since it was built?

You can't answer that question and neither can I. So common sense says that if a engine is new, and the parts are metal to metal, would it not be prudent even if not stated in the instructions to oil those parts?

Did you hurt it probably not. Could you hurt it, possibly.

Its not critical, and I don't write the manuals, I'm not an employee of YS. I'm a modeler just like you. I just happen to have flown YS engines for many years and have experience with them. I'm demanding of my equipment and do my best to keep it at the top in performance. In the competition world you can't afford to have problems with your equipment. The oil in the cam gear area is just that, a ritual I use to eliminate problems with damaging cam gears. Before I started the ritual, I might have had 2-3 cam gear failures in the previous 3 years. Since I have started the ritual I have not had a cam gear failure. Its been almost 5 years since I have had any cam gear trouble at all, and 5 yrs of oil before the first run.




Troy Newman
Team YS Performance

Troy,

Does fuel/oil get to the cam gears after a few runs or is this something that should be oiled manaully?

RcShacknet

It works its way down in there after a few runs. Mainly on the DZ engines this is an issue. The 110 has the fuel air mixture going through the bottom end of the engine and this helps lubricate it.

THE DZ engines are different. They only get fuel directly to the intake valve. So any oil that gets down below must work its way through the various passages and past numerous road blocks. Example, the DZ engines must get lube to the cam gear area. This can come a couple different ways. First it blows by the piston ring, then it has to work up past the crank shaft ring, then through the rear bearing, and into the cam area.

Another path is from the top down. It flows down the push rod tubes, and must get past the cam followers. These followers have tiny little holes in them to allow oil to pass. The holes are very small.

next option is the tubing that connects the lower end of the case to the fuel pump. This again is only on DZ engines. This line is for pressure to the pump, but some oil will drip down through this fuel tubing and get into the area.

These methods to lube the cam are effective if the engine is running, but let it be dry it might take a couple minutes of running metal to metal before it gets any good lube right?


Troy

Ed,

OSH stands for Orchard Supply Hardware. They have a good selection of nylon washers usually. I believe they are usually sold in 4 packs, but I don't have the part number or any other information at this time. The outside diameter is close in size to that of the thrust washer, the inside is somewhat larger, I just tack glue the nylon washer to the thrust washer with a couple drops of medium CA to keep it centered. Once the backplate, prop, and prop washer/nuts are installed it will hold just fine. I have attached a picture as well. I hope this helps.

Jim Smith

Troy,

I apologize for my ignorance on this YS engine. I guess I assumed that you were the resident expert here as you sign your posts with your name and Team YS Performance (This implies either Employee or Sponsored by to me anyway). I do want to thank you for your advice here, I just can't help feeling stupid that I didn't have the "common sense" to pre lubricate. I have had a few 2 stroke engines and this is my first 4 stroke. I know that with a 2 stroke, it is getting lubricated with the first amounts of fuel that travel through it. Where this 4 Stroke has no specific "oil" reservoir or pan I figured it was internally lubricated with the 20% oil mix in the fuel. I have learned the lesson that maybe one should scour the forums first on any new technology and find out how it is done rather than just jump into the manufacturers instructions.

I plan on trying to find a 0W or 5W Mobil 1 synthetic oil to use as has been stated in other posts. Is this the correct oil to use? As I remove covers on this motor to lubricate, is there any torque specs that I should know during the reassembly? If screw torque is not critical then I will plan on using some blue loctight and snugging them up. Also, do you know of any websights that will allow me to learn more of the in depth details of 4 stroke engines as they pertain to model aircraft. My ignorance on this stuff is my own fault and I want to remedy this.

Thanks Troy and everyone else for the info you have given thus far!

Shaun

Actually I am sponsored by YS. I am not paid by YS. SO yes there is a bit of a fine line there. Richard and Dave are changing their relationship in the business. Dave Shadel and Richard have been the importers of YS engines since about 1999. Before that Richard worked for Futaba Corp of America handling repairs and the importing of YS engines through Futaba Corp of America. Right now Richard and Dave have been partners since 1999 and Richard is in the process of buying Dave out. In the interim I have offered to help Richard out with the RCU forums in order to keep a valuable support system in place for guys that are on here and need advice on the engines.

There are some changes that are in process but things are not finalized just yet. The new website is up and operating, and Richard is trying to get some content on it regarding basic setup techniques and procedures. I'm sure some changes will be coming to the instruction manuals and also other things to improve the experience folks have with YS engines.

That all being said:

The FZ style or pressurized engines get fuel very similarly to your 2 strokes. It goes through the bottom of the case on its way to the big boom.

The cam gear is a part that is pretty far removed from the other internal parts. Yes oil will get there and actually it will get there pretty quickly in that first run on your engine. The DZ engines are the ones to really be concerned about. These are the engines that are direct injected. The fuel goes right up to the intake valve. Your 110 is not this way and its not as critical. Its a good idea on any new engine to oil it up, but on the other side of this coin if you put too much oil in on a new engine they can become difficult to start the first time. So any oil you add it doesn't take much at all.

I would bet that your engine is fine.

4 strokes are a little different and the major manufacturers do things slightly different. Saito vs OS vs YS all have their own little design that changes the needs for care and feeding.

The main thing is that the engine is not running lean and backfiring, on that first run. If it was lean and backfires and the cam gear is dry chances are its gone or will be soon. If you are not having trouble don't worry its fine. Just remember the next time out.

You did nothing wrong, and I ran YS engines for over 10years with never oiling the cam gear area specifically on a new engine. I really didn't have cam gear issues sometimes I would have a failure or a premature worn part, but as I got more experience with the engines I started doing this. Its a little ritual I do. I have searched the forum a bit and don't see much posted about it by Dave in previous months. So Obviously its not a critical issue to Dave and Richard. To me its a good idea. I will continue to do it. It doesn't hurt anything.

On the screws. I don't have toque values but if you have a torque wrench you can find the torque values for the small 2, 2.5 and 3mm screws in a standard machinist handbook. You don't need lock tight on these screws. make them tight but don't torque them down like a gorilla. Namely the carb, airbox, and backplate screws. tighten them in a crossing pattern to keep the part from warping when you tighten it. It should be tight, but not so tight you are threatening to strip threads.

I will do some research and come up with some torque values for the bolts on the engines.

I've never needed them before.

Troy Newman
Team YS Performance

Jim,

Thanks for the reply. We have no OSH's here in Georgia, but I'm sure Lowes, or Home Depot will have them. I like this idea if it works better than the emery paper and will give it a try.

Ed,
Not everyone has them, but most hardware stores that have bins with different size screws, washers, etc are usually your best bet. These washers also work well with nylon wing bolts to spread the load so maybe micro fasteners would have them as well (or anyone who sells that type of item can order them for you). On a side note I've used them on both knurled and smooth back plates and they hold up well......even in high RPM applications.
Good luck,
Jim

I use a washer made from leather to prevent slipage between the drive washer and the aluminum spinner back plate.

Troy, here is a link I came across from a freind concerning tunning on these motors. It is very in-depth and should make tunning alot easier even for a newb to YS such as myself. It seems to be a little old as it uses the .91 and not the 1.10. Would there be any recommendations for the 1.10 that aren't covered on here that are different from the .91?

I use full syn. high performance oil from CoolPower to prelube all my motors after purchase. Ususally I would disassemble and clean the motors with denatured alcohol prior to running, but four strokes are alot different than 2 strokes when it comes to this. So I just stick to lubing them externaly. You'd be suprised how how much material can be left in a 2-stroke after assembly at the factory. Mostly shavings from being machined.

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

Thanks Shane

Yes that is Phil Williams from the UK. He also is very knowledgable about YS engines and I will say his recomendations are good.

I tend to shoot a little higher on the rpms than he recommends but not too far off. Example is he says the 91 should be about 8800-9300, I'll go for a bit higher rpm and less load and say mid 9000's

The 91 and 110 are basically the same engine in this case.

Following his recomendations you will be fine.

Troy Newman
Team YS Performance

Thanks Troy, this will be my new bible for my feild box..

Shane