Altered1

Hi all,

I'm new to forum, and hoping I can get some help with my Enya .61XF, any suggestions appreciated

I've got her installed in a body board airboat. After 8 years sitting in the shed.

She's started, and run several times over the last few weeks, and seems to run fine until she reaches operating temperature.

once I get her to temp, she will surge like there is a fuel supply problem. This surging will happen at WOT, 3/4, 1/2 .... until she stalls

I can restart her no problem, but she only runs for another 30 seconds or so before she surges and dies again.

So far, I have replaced the fuel lines, wrapped the tank in foam, re-sealed the engine for air leaks, made sure the tank is level with the carb.

the tank I'm using is a 10oz tank that is mounted with the outlet level with the carby. It's an ENYA airbleed carby.

I do have vids if I am permitted to post.

This is so frustrating after I get a good solid 5 minute run from cold... then I end up cursing for the next 10 before I shut her down and go home. At the moment I am just not confident enough to put her on the wet stuff.

Lnewqban

Welcome to the RCU forums!!

It seems to be overheating due to either poor cooling or lean mix.

The easier test is running it on the rich side.

You could also try adding some Castor oil to the fuel.

Best luck with that!

jaka

Hi!
It's an easy fix! Take it apart and have a look at the ballbearings! If the engine was prevoiusly run on Castor oil it surely needs new bearings after sitting for 8 years.

1QwkSport2.5r

You came to the right place, Mate. (This is Legal v8 from RCAW) Post your videos - these guys can better help diagnose the trouble with a video.

NM2K

My Feedback: (14)

Of course, you ARE burning model airplane fuel and NOT boat or car fuel. Right?

Stock Enya engines used to be set up to burn 0 to 5% nitromethane content fuel with 20% lubrication (castor or synthetic or a blend of the two). If using more than 5% nitromethane, you might have to add an extra head gasket or shim in order to lower the compression ratio for burning higher nitro fuels. Especially, if you are running the engine with a prop of larger load than an 11x8 or 12x7. Prop size should be from an 11x7 to a 14x4 or 5 and all in between.

Frankly, the first thing that I would check is the fuel tank vent line. It sounds as though it is crimped or partially plugged, but all of the aforementioned problems could be at play too. If it is a previously unused engine, it could be in need of a simple break-in.

Our model engines do require special running right out of the box before we can tune them for maximum safe rpm and then operate them on models. Some folks do not follow this simple practice. They are usually the ones that call engines "junk" a flight or two out of the box and after they have trashed a model or two. Life goes on. I look for these types of folks and try to buy their junk engines from them. There is usually nothing wrong but the need for a decent break-in.


Ed Cregger

earlwb

I would concur in the opinion that the crankshaft bearings need replacing. As the engine heats up the space between the crankshaft and crankcase opens up and it starts to suck in air past the bearings. If I remember correctly the front bearing was a sealed or had a dust cover on it and the rear bearing was open. So in your case the engine is sucking air in past the front bearing. That will cause the lean running and surging when the engine heats up.

downunder

You say you have an airbleed carb (some of the 60X's did come with a simple air bleed carb) but does it look like the one in the photo? The idle is an airbleed but the lever with the graduations is the midrange adjustment and is quite sensitive. Towards the + is rich and the - is lean and should be set to the centre initially. There were also many different size carbs used on the various models so hopefully yours is about an 8mm and not the extra large carb used with a geared fuel pump . How fresh is your fuel?

There were several versions of this engine and you'll most likely find a Roman numeral stamped on the side of the left mount. Mine has III stamped there. I've only ever run mine with straight 80/20 all castor. If in doubt about the bearings, just take off the front housing and flood the bearings with acetone, that'll dissolve any old gummy castor.

Altered1

Hi all,

Thanks for your suggestions.

to add a few details, I am currently running 10% Nitro Aero fuel, no synthetic. Spinning a 11x7 Prop. The engine has done several flights in it's previous life in a plane, and was run on FAI fuel. The 10% at the moment was all the shop had for planes.

The Carby has the hole at the front and the associated screw, but no mid range adjustment as in downunder's post.

i1211.photobucket.com/albums/cc434/Altered01/IMG_6239.jpg
i1211.photobucket.com/albums/cc434/Altered01/IMG_6236.jpg

Fuel tank vent line is new, and fuel had no trouble moving back up the line to the exhaust when the tank was full. I will take off the nipple and clean.


The vid: s1211.photobucket.com/albums/cc434/Altered01/

Lnewqban

In your case, the oil content is more important than the nitro-methane.
Check that the total oil is 18% ~ 20%, no less.
You either got a mix of Castor and synthetic oils in the mixed fuel or synthetic only.

I can see in the videos that the cooling is great; hence, lean mix or obstructed exhaust is the problem, I believe.

http://www.osengines.com/faq/faq-q654.html

Yes, you can tune the mid range with that air intake little hole; here is how:

http://manuals.hobbico.com/osm/40-46-65la-manual.pdf

Kweasel

My Feedback: (29)

Remove the rotating barrel and clean the mixture slot. Clean all the fuel passages while you're at it. The G8 is a good carb but will plug easier than other designs so always use a filter.

Mr Cox

That is not correct, the midrange on this Enya carb is controlled by a slot in the throttle barrel. The barrel is very easy to take out and clean.
The airbleed screw only affects the low end.

Altered1

Thanks everyone,

I'll break it down and give it a solid clean, from barrel to exhaust.


The airbleed is locked off at WOT, and inneffective when throttle closed.

Mr Cox

Don't clean the piston and cylinder, that is just asking for trouble as you will loose the all important castor. A simple cleaning of the carb is probably all it takes.
If you do take it apart then also check that the conrod is moving freely on the wristpin. Castor can freeze this up and then it wears on the piston instead.

Altered1

Today, I took off the carb, and broke it down for a clean.

It's too windy to take her out, so started her up in the back yard. - summary: problem still there.

I didn't get around to checking the bearings, apart from spinning the engine and looking / feeling for any slop. Everything seems tight. The bearings rotate smoothly, and there is no back and forward movement. Do I need to take her apart? If so, what am I looking for in a failing bearing ?

Once I got the engine warm, just because I had one in the flight box, I tried a ENYA #3 plug, which I see is similar to the OS#8 I was using, I can tell you that she ran a lot rougher, coughing and missing. Would it be worth my while to try a hotter plug, or an idle bar plug?

w8ye

My Feedback: (16)

I was thinking that a Enya #3 was pretty hot.

If the bearings are smooth and tight, don't take the engine apart if you do not need to.

Altered1

I've seen references to the ENYA #3 and the OS#8 being roughly equal, and the Enya plug was what I used when the engine was in my Senior Telemaster.

I don't want to hijack my own thread, but....

From Enya website:

No.3	HOT	For standart engines It is supported all 2 cycles 4 cycles engines.				EP00003
No.4	MEDIUM-HOT	For standard engins It is supported all 2 cycles 4 cycles engines.				EP00004
No.5	MEDIUM	For hot engines A helicopter or a car to use in high temperature, high speed				EP00005
No.6	COLD	For competitions For high speed, long ranges with a high compression engine				EP00006

Cheers
on the bearing info

w8ye

My Feedback: (16)

The OS 8 is a medium plug

The hot OS plug is the A3 or at least it used to be

The Enya #3 is a hot plug If you engine sounds ragged with it, the engine may have detonation and preignition?

Altered1

I think I'll have to get a range of plugs then... oh bugger - that means a trip to the LHS.... how unfortunate !

I'll try a cooler one.

downunder

Actually it mightn't be a bad idea to take off the front housing because that's an easy way to check the bearings and doesn't disturb the rest of the engine. As Mr Cox suggested it also gives a chance to check that the rod is free to move on the wrist pin. With the piston at BDC, hook an allen key behind the rod as far up inside the piston as possible then pull with the key and push back with a finger. If you feel the rod move a little then all is good. If it doesn't move then invert the engine so you can fill the inside of the piston with either fuel or acetone then continue pushing/pulling on the rod until it frees up.

You didn't mention if the Enya #3 was a new plug or an old one in your field box. If it was an old one then try a new hot plug. Also, was the rough running at idle or high throttle setting?

Altered1

Hi Downunder,

The plug was old, and the rough running was at all speeds.

I'll take the plate off and have a look. I'll also have a look around for a video of someone breaking an engine down.

Cheers!

Altered1

I took the prop washer off, and had a look at the front bearing. both the inside and outside of this bearing rotate. It is not an interference fit, and given that right behind this is where the carby drops it's air fuel mix, I can appreciate how it could be slobbering rich in the carby, but lean in the combustion chamber. So it looks like I'll be doing some bearings. But there is no slop in the bearings... thats odd ! I'm right that the bearing shell should be interference fit to the engine body, right ?

I tried to take this plate off the engine, but chickened out when it didn't give easily once the bolts were removed.

I then found a video where the guy put new bearings in t thunder tigre .50... so I know what I have to do. I'm just amazed at how little information is out there about bearing sizes !

[img]file:///F:/DCIM/100CANON/IMG_6241.JPG[/img]

downunder

The outer race of the bearing should be a light heat shrink fit in the crankcase and definitely shouldn't rotate. It also appears to have a rubber seal which would indicate it's probably a sealed bearing that someone's fitted. Unfortunately that really means you need a new front housing which is most likely still available from Enya.

The front end of yours is slightly different to my 60X-III which doesn't have the raised part around the front bearing so I'd guess yours is either an X-I or X-II so I'm curious as to whether yours is ringed or AAC.

jaka

Hi!
Do you really mean that the front bearing (the outer part) rotates in the engine housing???

Altered1

That's exactly what I mean Jaka

So it will be sucking air, and leaning out the mix before it gets to the combustion chamber.

Downunder, its a ENYA 60 XF TV AL-CHROME. The paperwork that came with the engine lists 4 .60's - this one, and the II and IIIB and IIIB TVG-8.

That bearing is Japanese.... could it have been from factory ?

jaka

Hi!
If the bearing rotates in the housing you have to replace the whole front housing.
See to that you get either C3 or C4 ball bearings, shielded or not is not important.