Whats the Webra going for $$$$$$$? What pipes are being run on it? Thanks, Chris

Hello Chris,

I bought my for $ 438,97 from [link=http://www.centralhobbies.com]Central Hobbies.[/link]



Danny

Hello everyone,

I’m currently gathering information on how to Break-in my 1.60 with the MC-Carb.
And I would like to know how should I put the Mix curve.
In the Instruction manual for the MC-Carb they said it as follow:
If you are using a transmitter which features curve Mixers, it is essential to check
at the control servo mixer really is set to ‘linear’. Once you have established this, open
the carburetor barrel by about 1 to 2mm, and start the motor.

Has anyone done this before?
And if not, could you tell me how you did you set the mix for the MC-Carb for Breaking in.?


Any comments and or suggestion will be appreciated.

Danny Koolman

What kind of radio do you have???

My radio is the JR XP8103.


Danny Koolman

The 8103 handles a bit differently to the 10X, so I spent 1/2 and hour exploring and documenting the
Radio using an MC Carb. The result is the same as the 10X but it is a different journey.

INITIAL STEPS
Plug in the throttle servo to Throttle Ch-1 and the mix servo to CH 7 AUX-2.

Go to AUX-2 end points and set the values to 0% in both directions. This prevents you from accidentally spoiling all you settings by moving the AUX-2 rotary knob.

MIXING WITH THROTTLE
Select Mix -1. This mix has a 5 point curve labeled “L-1-2-3-H�

Choose Throttle to Aux-2. (Aux-2 is control knob is not used. See below when Aux 3 is mixed in.)

Use SEL key to scroll down to Point-line.

1st question is “Expo Curve�. Say yes with + or – key.

Use <CH-key to select first point “L�. Hit clear key to move graph to center line.

Use <CH-key to scroll across to select last point “H�. Hit clear key to move graph to center line.

Leave mix switch-setting = ON

The mix is now set so that you can run your engine. The mixture is electronically set in teh middle so that you can adjsut either way. Position mix arm vertically to MC-carb using guide marks on carb. Set mix servo arm to center position. You could now run the engine and set the mix values using the positions on the “point-line�. The problem is that the mix may initially be lean or rich and you will not be able to “Beep� quickly enough to adjust the mix while the engine is running.


MIX-1 OVERIDE KNOB
To help you set the motor initially AND to also give you “run time� overrides in flight etc, you can also mix another channel knob to work the mixture servo. I put this mix on a switch so that the primary mix is guarded against accidental knob rotation.

Select MIX-3 (because it has no graph.)

Chose AUX-3 Ch-8 to AUX-2 Ch-7

Turn the AUX-3 knob all the way counter clockwise. This is richening if it were a needle on a motor.

Using the + or – keys set 30% mix so that it moves the mixture arm in the direction of richness.

Turn the AUX-3 knob the other way – clockwise – and dial 30% of mix to lean the MC Carb.
(30% seems to be a sensible, “not too rich, not too lean� choice that prevents you over adjusting in-flight)

Drop down the menu and chose a switch. Mine offers Gear or Land s/w. I chose Gear lever because I have fixed gear.

Now you have a fuel mix control that will allow you to turn it on, start the motor and rotate the AUX-3 knob to richen or lean at all throttle positions.

In initial set up what I do is open the menus to MIX-1 so that I can adjust the mix graph.

Select point position 1.

Turn on the override-mix-knob.

Start the motor and move the throttle to Point-1 position on the graph. Adjust the mix with Aux-3 knob.

Then reproduce that setting with the + or – keys on the graph at the same time as backing-off the override knob position to its mid-point. Switching off the mix override confirms the graph mix.

You do this at each point-mix("1 - 2 - 3 H"), gradually going up in rpm. Then you go back to the “L� point and set the idle mix. You soon get pretty good at setting the mix with the graph-mix-function.

In normal use leave the override-mix “off�. Sometimes I use it if it is cold and the 2-c needs a little bit more fuel of if I have flooded the engine I close the mix for a few spins of the motor.

One trick is to leave the override a set a little lean. Then if the engine loads-up on the flight line I “click-in� a lean mix and then “click-it-out� when airborne.

Hope this helps.

Hello Eric,

Thanks for the info.
It seems that you help me out, but I will know for sure when I try it out.
Hope fully I will run my motor in early July.

Again thanks for the info,

Danny Koolman.

.

Hello everyone,

I’m currently setting up my engine, ok better said a friend off mine is setting it up for me.
(Aruba Maverick aka Chee Chong)
I don’t understand this engine (MC-carb) yet.

Now were wondering what RPM we should get it at full throttle, and idle.
This is my set-up : I’m using Morgan’s Coolpower 10 % Nitro
The prop is a 17X12 APC.
The plane is a Focus II
Elevation is non, were at see level



In advance I thank you for the info.

Danny koolman.

As a reference, my 160 is turning in the 7700 plus rpm range on 15% nitro and a 17X13 APC. I like to leave my top point of the mixture a touch on the rich side. Idle should easily be around 2000 - 2200 rpm. I really don't bother with taching my motors much. I listen to the engine and observe the exhaust smoke trail. Make sure your pushrod on the mixture side does not flex a lot. Sooner or later from wear and tear the mixture side barrel may get stiff causing enough resistance to make the pushrod flex and not give you a consistant mixture. You also need to listen to the engine in the air. Listen for a harsh sound at various throttle settings(usually in the 1/4 to 1/2 throttle position) that almost sounds like a pushrod rattling. I it does you need to richen a few points on the mixture curve(usually the 1st 3 points on a 10X 7 pt mix).

Make sure you get ample cooling directed to the main bearing and the pump area.

Hello jlachow,

I’m getting @ 7700 RPM on my set-up.
Idle at @ 3000 RPM.
I have the rattling sound like you’ve explained, but mine happens only in flight.
When the engine is running at the ground no sound at all.
We thought at first that the pipe was hitting some where, and we had a look, and doesn’t
appear to be so so. That I’ve thought it was the elevator pushrod hitting inside the plane.

Could you explain more precisely what I could do.
I’m using a JR XP8103.

Thanks in advance for the info, it will be greatly appreciated.
Danny

If your engine is rattling in flight you have it too lean at that point, so you need to richen the mix. I have mine set to an idle down of 1700, and normal idle of 2000. I get max of 7800 rpm on a 17x13apc and 15%.

Im not familiar with the 8103 but assuming you have a 5, 7 or 9 point curve slaving the fuel valve to the air valve, you need to adjust the point at the stick position where the engine rattles in flight to open the fuel valve more.

I also found the mix side barrel to be stiff when new and had to free it up by lapping with toothpaste, oddly when dry the barrel didnt bind but when fuel was added it stiffened up. The small servos I have used also wear out; and I had a ball link strip the threads. These things caused me some troubles.

You should be able to acheive an idle lower than 3000, if the engine is rich on the idle side it may die after snaps. The high idle RPM makes me think it migh be rich. I have begun taching my engine for high speed and idle, I insure 7700rpm or better and a 2000 rpm idle before flight. It just helps my comfort level.

Glad to see Ivan skirted your shores. I didnt realize Aruba was considered outside the hurricane belt, maybe we should spend our vacations in Aruba.

Funny, I have just the opposite happen to me, mine got stiffer with time. On one of my carbs I replaced the mixture barrel and o-ring after about 100 flights. The in flight banging is what I think really shortens the bearing life in addtion to the rust.

I use a JR 4231 on mixture and a 368 on throttle barrel. Both are digitals.

Find out which point on the mixture curve is closest to where the stick is when it bangs and then richen that point a percent or 2 at a time and do the same for the point before and after it and see what happens. Make sure your transition is still good. I think you may also get a better idle with a higher nitro fuel. Most everyone I know running these motors in the states is using 15% nitro with anywhere frome 16-18% oil. Like I said before, the cooling of the main bearing and pump area are important too.

I had two of the MC barrels get tight after about 2 gallons of fuel on my 1.60's. This was something that did not happen with my 1.45's last year.
If the MC barrel is sticking, it is nearly impossible to tell until you see it acting up on the ground with the engine off. The symptoms I experienced were that it could quit at any throttle movement, opening or closing from any throttle position.

Here is what worked for me.
I switched from a cable pushrod to a .050 steel rod. (you could try smaller diameter, this is something I had on hand)
My servo is a small JR 341, so I maximized leverage by going to the inside hole on the servo. Being careful to maintain enough throw for the MC barrel.
This next part can be touchy so be careful if you try it. Disassemble the carb and remove the MC barrel. Take off the small o-ring and find a small file that fits the groove where the o-ring came from. Chuck the barrel in a drill press and turn it at a very slow speed. Just barely touch the file in the groove a time or two to make the grove .003 of an inch deeper. Clean it up good and put the o-ring back on and put the carb back together. If the o-ring is at all damaged, replace it. It should now move very free now and even easier after flying.

As I said, it is a delicate process that I am sure would void any warranty.

The only time mine quits now is when I run it out of fuel. It has been very reliable and smooth for hundreds of flights since the change.

Bob,

I have since gone to steel wire, as well. Do yu have any idea what the dimension of the O-Ring is. Spending around $20 for a couple of o-rings and some e-clips is obsurd. Especially when all you need to replace is the tiniest o-ring. Will also consider the milling thing in the future.

For deepening the o-ring groove you could probably strip some fine sandpaper if you dont have a file small enough.

If you find your own o-rings investigate the material type so its compatible with the fuel. When I happened upon this problem I considered a silicon o-ring but couldnt find one as fast as I wanted it.

I have taken to running my cylinder to tdc and holding it to let off compression closing the exhaust port for storage. This at the suggestion of Verne Koester (sp?), hopefully to prolong my bearing life. Just an experiment at this point.

Hello Joe,

I find it difficult to measure the o-rings. And I am using the parts from Webra.
Like others, I would be interested in a silicone o-ring supplier.

If you have one of the old o-rings and can get some dimensions, like the thickness id and od I can check a catalog and pick out a number for you. Its probably a metric size, the o-rings come in standard sizes so I would select several sizes if in doubt. You could also measure the shaft size, bore, groove width and groove diameter and select a size from that.

Probably what you will find is in this size someone will want to sell you 200 for $20.

I bet webra produced some parts out of spec, so even a new o-ring might bind unless the groove size is corrected.

Hello Everyone,

I’ve richen the fuel mixture, but now at mid range it has some problem.
When I go from idle to mid range, it hasted for a few second and than begin
to pic up speed. A friend Chee Chong, who is helping me, was telling me that
that is a sign that it’s to rich.
I’ve checked inside the cowl and yes , there is plenty of oil. It doesn’t seem to
be lean at all. But didn’t got the chance to try it out, flying it.

Any help please. Everywhere they tell me it’s easy, but frankly I don’t see the easy part.
(Getting frustrated) [sm=bananahead.gif][sm=bananahead.gif]
Do I have to do some setting on the fuel pump? [sm=rolleyes.gif]
I’m now waiting for my hobby shop to get Morgan’s coolpower 15%.
Could that be the solution?[sm=rolleyes.gif]

Thanks in advance for all the help suggestion.

Danny koolman.

I didnt find it easy, but with patience and being careful the engine will run well. You want to avoid the lean runs for sure, I pinch the fuel line as described in the manual, if the engine picks up rpm in a few seconds then slows down its set about right at that throttle point. If it stalls immediatly when you pinch the line its too lean, if it takes many seconds to pickup rpm then its too rich; adjust you mix curve accordingly at that point. If it hesitates as you describe it is probably RICH, try leaning the mix and see if it improves, if it does your on the right path.

This will get it close to fly, final adjustments will be made in flight.

I didnt adjust the pump on mine. Pay attention to the mix valve as described above so you know its not sticking.

Im not sure fuel would make a differencel, 15% nitro is what I use, I have used 3 brands succesfully.

Hello byoung466,

Did you mean lean or rich, it sound like it too rich. ( well for me )
The first lean that you mention.

Thanks,

Danny Koolman

Now that is my only problem I thinks Getting for 2 to 3 point on my radio. It’s a JR XP8103. It has 5 point curve.

woops... I meant rich...sorry.

I use the Futaba 9CAP, it has 5 point curve also and works ok.

Pro Pattern,

Eric listed a good setup procedure for the 8103 at the start of page two on this thread.

Get your radio set up so you can turn a knob at any time to test if you are lean or rich.
Then you can get set up close on the ground and test to a finer point in the air, then land and reset a point or two on the curve mix.
Pay attention to how much a click on the knob moves your MC linkage. This will help when trying to match it's movements with a throttle point setting after testing in the air.