stalling

[joe1960]

Hi: I have a OS 61FX engine which is new. I proceeded to run in the engine with a few tankfulls of fuel. I did what the instructions said and noticed a pinging kind of noise at one point as if it were running hot so I richened the mixture and that problem ceased. I notice however that in the air as well as on the ground that when I thottle up sometimes it will either stall out or hasitate. I have adjusted the low end needle and was wondering if it just isn't broken in enough yet or am I missing something. Thanks, Joe

[tandemairbike]

Have you tried changing the glowplug? The original might have been damaged by a short , hot lean run.

If that doesn't work try slightly richening the idle mixture.

Tandy

[Artisan]

Glow engines must be ran slightly rich. That means you need to open the needle valve (high speed only) more than when tuned for absolute peak rpm in order to have sufficient extra fuel to help cool the engine. It also helps to compensate for the leaner and leaner mixture the engine will have as it burns fuel from the tank.

Always err on the side of running too much fuel through the engine. Too much fuel will not hurt the engine. Too lean of a mixture for prolonged periods can ruin your engine.

Is your engine equipped with a piston ring? Or is it non ringed? Non ringed engines do not need much of a break-in, while ringed engines take slightly longer. Both benefit from being ran in a slightly rich two-stroke. You should not run either engine in a four-stroke (so rich it sounds like it is missing every other beat).

Follow the instructions to a tee and you will be okay. Just always err on the side of being slightly richer than peak rpm. Good luck.

Ed Cregger


Addendum: The low speed mixture screw is the one that has the most effect on adjusting the engine to transition properly. You can try tweaking this needle a little bit to improve the transition.

But you are right, in that the engine will improve in its running characteristics the longer you run it. Check your carb needles frequently. Your engine's demand for fuel will change quite a bit during the break-in process. Generally, you will have to lean the mixtures a bit as the engine breaks-in. But don't be in a hurry.

That noise that you have mentioned could be the result of running too much nitro in the fuel. Two-strokes run best on 5% to 15% nitro. Using 30% nitro left over from heli or boat use is not the best idea.

[Abraze79]

Can you tell me how many turns the needle (the needle adjusted with fingers) must be turned when running in a engine? Its a SC .46 engine

Andrew

[tandemairbike]

With the engine stopped, close the high speed needle( the one turned with fingers) all the way and then open it 2 to 2 1/2 turns. Start the engine and with the throttle wide open turn the needle in until the engine oscilates between a fast four stroke and a smooth 2 stroke mode. When the model is picked up and the nose is pointed straight up the engine should run in a smooth 2 stroke mode without stalling. If the engine stalls it is too lean. If it will not maintain a smooth 2 stroke operation but still oscillates between 2 and 4 stroke engine is too rich. After the high speed is adjusted properly the idle speed can then be dialed in.
Hope this helps.

Tandy