kwik

Hello,

I have been doing lots of adjustments and testing lately on the FG-57 gasoline twin.

I will mention a few things here which might help others in the same situation as me;

A novice to 4 stroke gasoline twins.

My FG-57 is now giving 6500 rpm with a Mejzlik 22x10 , and the 50cc ESM Corsair is very agile in the air.

I am extremely happy with it; A wonderful engine.

Here are my list of tips and trix;

1) The tubes from the common carburator to the gas inlets on the cylinders are of different length.
The right cylinder has a shorter tube than the left. This is because the left cylinder is more forwards than the right cylinder.

Anyway, for some reason it seems the right cylinder always gets a bit more fuel than the left cylinder.

I dont mention this because its a big turnoff to me, its just that it gives some effects that is nice to know about;

If you lean the L needle to much, the left cylinder wont get any fuel, and it will only run on the right cylinder. In this case there is nothing wrong with your ignition; You must adjust the L needle to give a bit more.

If you let the L needle give a but too much fuel, the right cylinder will start couching and spittin and the idle will be erratic. The rpm display will start to flicker because the measurements are erratic. Again; Nothing wrong with the ignition, just lean the L needle a bit.

If you lean the L needle a bit more when running on only one cylinder, it will suddenly refuse to start at all, of course.

If that happens; If you somehow has adjusted the needles so much that you have "lost it"; It refuse to start at all; Look in the manual for the factory setting. Put it back on factory setting, and it will most likely come to life again. And you can start adjusting again. It will be almost impossible to get it starting again by just trying random settings on the L and H needle.

When you are doing all this, have a strong starter at hand....hand-starting it will lead to exhaustion at this stage; That must wait until it is properly adjusted.

Here is mine;
http://www.himodel.com/helicopters/1...rive_Cone.html

I made a wooden box at the bottom part of it, containing 2 A123 batteries. It is geared and gives quite a soft starting.

2) If the engine hasnt run for a few days, it can be difficult to start.

This is how all Walbro carburators can behave. BUT;

Choking it using the tool that comes with the engine can fool you; It would be smart to read the manual and carefully follow the procedure there when choking. Otherwise the choking doesnt do what you expect it to do, and it wont get any fuel.

Therefore, what I do is choking it by using my finger on the trumpet opening, and use a starter. It works every time.

If anyone is interested in how the pumping actually happens, I have made a video explaining it;

http://www.youtube.com/watch?v=5GW82csWkNk

Somethimes it actually helps to understand how things work; It is easier to remedy the situation.
When that area is dry, the lips might not be seated properly, hence no vacuum effect in the pump, and the membrane won't be moving.

Again, this is common to all engines having a walbro carburator, not just this one.

3. The carburator is VERY sensitive to what kind of oil / how much oil you have in your gasoline.

For example, if you tell yourself you are now finished breaking it in, and change from 5 % mineral to 3% fully syntetic racing oil, I can guaranty you will get a surprise. ( Personally I will continue using 5% . I think it is important; The conrods have no bearings at the crankshaft end.)

You will most likely be on issue 1) in my list here, and will have to start adjusting the L needle again. It might even refuse to start.

So, if this happens; Set needles back to factory setting, and start adjusting.....

Therefore, when mixing a new batch of gasoline, be careful and measure the same amount of oil each time. And if you switch oiltype, be prepared for adjustments.

4) When the engine is brand new, there might be little or absolutely NO oil in the cams-valves and crank case. This could damage the engine. This is explained in the manual....

I put my engine upside down, with the carb and venting nipple upwards. Easier to choke, and I can fill oil into the venting nipple. I have a tygon tubing on the venting nipple, which I can use for filling oil.

After all, when you think about it; Where should the crankcase and the cams/valves get oil from, really? It has oil in the gasoline, and no oil-tank. The gasoline gets sucked into the piston-chamber, explodes, and is ejected through the valve to the exhaust output. Thats it. All I can think of is some leakage via the piston rings and perhaps through the valve-stems? I dont know, but some fresh oil into the vent nipple must do wonders for the lubrication.

5) My engine came with ignition version 2.0 . No matter what I did whith the L and H needle, I could get only 5000 rpm with a Menz 22x10.

Very dissapointing for a few hours.....Well, to tell the truth I despaired...but told myself, relax, let it rest for a while, and perhaps an idea pop up.

And an idea suddenly emerged;

I loosen'd up the two screws holding the sensor a bit, so that it could be moved if you applied a bit of force. This so I could move it while running.

I moved it a tiny bit at a time, very carefully; Did not want too much advancement. Just to see if some more advancement would give more max rpm. And it did. I stopped when I got 6500 rpm on a Mejzlik 22x10. Very happy! Hopefully this won't damage the engine....I didn't dare move it more than that; About a 1/4 inch ( 0.6 cm).

Pete Bergstrom

These are all great tips! Thanks for sharing.

Pete

w8ye

My Feedback: (16)

I would keep the oil at 5% or 20:1 even after break in and running your Motul synthetic oil.

The detail about priming the engine with the carb tool is that the throttle must be closed when pulling out on the throttle barrel.

Simple just to use your thumb like you say.

Rudolph Hart

Kwiks thumb knuckle must have eight joints in it if he is manually priming the engine every start

kwik

Ha ha!!

I installed the engine "upside down". So the trumpet is pointing upwards. And 2 big hatches covering the upper 50% of the radial cowling.

I like access to the engine.

Normally I only need "manual priming" on the first start of the day. The next one is firing right away.

kwik

Yes. Will keep two cans of gasoline from now on; One fourstroke 5%, and one two stroke 2%.

The Bel Ray oil is simply too expensive here in Norway to use 5% for the 2-strokes.

w8ye

My Feedback: (16)

+1

Rudolph Hart

Over here belray are well known motorcycle oil suppliers,good one's too have used them.As far as i can remember oils made for m/c's have a lower flash point and tend to burn around our fourstroke exhaust temps

kwik

So, are you saying it is not so smart using the Bel Ray H1R on the RC four-strokes?

http://www.belray.com/bel-ray-h1-r-r...-2t-engine-oil

Rudolph Hart

From what i've just read in your link i think so.How did you damage the first engine?

kwik

If I tell it here, it will only create lots of discussions and theories.

Rudolph Hart

Fire away friend

kwik

The Saito FG-57 in action again. First flight on our airfield this spring.

Life is good.

http://www.youtube.com/watch?v=8oK44...ature=youtu.be

FlyandMighty

Kwik

I wanted to know if you have any baffling in you cowl for the engine. I have the same engine in a tf fw190 and I'm getting some overheating.

T

Rudolph Hart

Good baffling is essential to the longevity of these gas fourstrokes.Rather than explain it longhand here i recommend you go to pe reivers site for an in depth explanation on cooling.

FlyandMighty

Old fart
I have seen that explanation. I was referring to Kwik because he like me has a cowled 57t. But thanks for the response.
Do you have one of these engines?

Rudolph Hart

Yes,it too is tightly cowled in a 92" 540 v3 edge

FlyandMighty

I'd like to see your baffle set up. do you have any pics to share?

T

MKnutson

I've got mine in a GP Ultimate bipe 160 and it flies it great. I haven't had any cooling issues with it yet short of the carb getting heat soaked after a flight, then trying to start it with the carb hot.
Watch the cam lube! They run real dry! I like to inject some oil into the breather tube then tilt the nose down so the cams get drowned with oil.

Mark

FlyandMighty

So when th carbs hot it won't start? Mine does that. I am having overheating issues but i needto get more air running through it.

MKnutson

I found out after flying that the heat from the engine soaks into the carb after being shut down for a bit and it gets a little vapor lock. I just let it cool for a bit longer before the next flight.

Mark.

JamesPool

My Feedback: (3)

Hello. I just read your post and everything you've noted is exactly as I have experienced. Thank you for a well written summary.

I adjusted the timing as you noted and I'm now able to get my 57t to reliably maintain 6300rpm. Prior to adjusting the advance, I could barely reach 5900rpm with a xoar 22x10. My motor is mounted vertically so I think I'm also fighting a notably richer bottom cylinder too.

With this said, are you having any issues with your increaded timing?

Thank you,
james

FlyandMighty

why would saito not set it up to the highest rpm from the factory? Are there cons to moving the spark timing around? what is the factory setting?
I look at mine and it's clearly not the 28 degrees BTDC that I have read is the sweet spot for 2 cycles.

JamesPool

My Feedback: (3)

I don't know what the original/factory timing is or even if my motor was setup correctly, but I know from my nitro boat racing days that if you get the timing too high performance is erratic and unreliable.

With this said, I plan on digging into this more.

FlyandMighty

I talk to Horizon and they say that the factory timing is to set the sensor up evenly between the 2 screws. they do not have a spec for how may degrees BTDC the timing is. Saito has not provided Horizon with that info and it is not in any service info that they posses. 5900 RPM is the normal RPM for a 22x10 prop according to my sources at Horizon.