72cheyenne

Hi folks, I have been out of the hobby for a few years. Now I am getting back into it and have a little fun fly plane that takes a My O.S. .32 sx. The engine is cleanand turns over just fine, but it seems like it has to much compression and I cant get it to turn over more than once with the electric starter. I am using a dynatron hi torque starter with a full battery. Also tried another cone on a cordless drill which keeps turning but the prop doesnt. Even using full spinner for more traction. Itried using chicken stick and it fires but doesnt start up. I never had good luck with the sticks except on bigger engines. Could someone please point me in the right direction? Any help is appreciated. Thank you
Nigel

Bax

My Feedback: (11)

Your engine is an ABC-type of engine. This means that the particular construction of your engine has an Aluminum piston, and a Brass Liner that is plated. Traditionally, the plating was Chrome, but some engines use a different metal, usually a nickel alloy.An ABC-type engine will have the cylinder liner manufactured in such a way that it is tapered towards the top. This will cause the piston to jam or "grab" as it moves towards Top Dead Center. Some engines will actually seize if you turn them over when cold, and will require considerable force to turn them through the jammed area.

You may feel something that you may interpret as play in the connecting rod. This is almost certainly not the case. What you are feeling is a slight springing of the connecting rod as you force the engine through the top of its stroke. The piston doesn't go all the way to the top, and the rod will flex slightly, which gives an "over the center" feeling. Many people have interpreted this as play in one of the rod ends.When an ABC-type engine is run, the heat of combustion will cause the metal parts to expand. Because the piston and cylinder liner are made of different metals, they will expand at different rates. The cylinder liner will expand just enough to make a nice fit for the piston once the engine warms up. The liner is tapered because it is hotter near the top of the cylinder than lower. The different temperatures cause different amounts of expansion.

Your ABC-type engine must be broken-in at full throttle. You don't want to run it too rich. Too-rich running will not allow it to warm up to proper temperatures. Lean it until it is running just out of what is known as "four-cycle" mode. You can lean it to peak RPM as soon as the engine will accept it.You should prop your engine to allow it to turn up. ABC-type engines work better at higher RPM. You should also use a fuel that contains castor oil in the lubrication mix. Castor oil helps the engine run well because it's still the better lubricant for ABC type engines. All-synthetic fuels have been known to cause difficulties in running, at times.Once properly broken-in, your ABC-type engine will serve you well and deliver lots of reliable performance.

Mr Cox

If the engine is brand new you can preheat the cylinder with a heat gun or small butane torch to remove some of the pinch at TDC before the first start. Once the engine has been run in, you will not have to pre-heat it anymore.

kmeyers

Pre-heat is what the alcohol guys do with there cart engines and is good for startup of a new ABC.

But if this engine has been run before removed from storage cleaned and fueled and now won't start. Sounds like it might be flooded.

1QwkSport2.5r

+1. A fully charged battery on a Dynatron won't turn an ABN OS engine over? Yeah, probably flooded. Dynatron starters turn over 100cc gas engines with ease... Hopefully the OP hasn't bent the conrod from their attempts to start the engine.

72cheyenne

Thank you for the advice. I will try heating it up first today and see if that does the trick

1QwkSport2.5r

I would first ensure the combustion chamber doesn't have a pool of oil in it or that it's flooded first. I'd also suggest hand flipping it a few times before putting a starter on it. This will also give you a good idea of how tight the cylinder fit really is. The Dynatron starter is a heavy duty unit and should start that engine without breaking a sweat.

jaka

Hi!
Sounds flooded to me! Just see to that the fuel in the combusting chamber is poored out, you turn the prop over and at the same time tilting the engine over to the side so the exhaust port is pointing down.
Then flip the prop over with two of you fingers and it would start easily! See to that you have a glow driver and not those tiny 1,2V batteries that you put on top of the glow plug, those are not adequate for a newbie. Instead you a 12V, 9amp motorcycle battery (or better yet , use four 3A LiFe cells in series ) and a "glowdriver" that converts the 12V to 1,5v for the glowplug!

1QwkSport2.5r

1.2v glow drivers work just fine. Just make sure it's fully charged.

Mr Cox

They are not beginner friendly though as the voltage will drop off fairly fast after some fiddling with the engine and will then not have enough juice for a wet plug...

1QwkSport2.5r

I disagree. They are all I ever used even when new to glow engines (in RC cars) and never had an issue. My first glow powered car had an easy starting system that heated the plug and started the engine at the same time. I found that more cumbersome than using a standalone glow driver so I pitched the starting system before the 3rd tank of fuel and went to a rechargeable glow driver and never looked back. If an engine won't turn over with a beefy electric starter, then common sense should kick in to remove the plug and dump the fuel out of the engine. Or at least hand flip it without the glow driver connected to verify it isn't flooded. If a glow plug is wet, a field box glow driver will do no better to dry the plug off than a standalone glow driver would. At least in my experience anyway.

rcguy59

My Feedback: (8)

That's really weird. I have several 32SX's and have never had that problem. Gotta be flooded.

jaka

Hi!
Not for the gentleman I helped last weekend!

Too Little power in those tiny C-size nickel cadmium /hydride cells when you are a totall new bie and it takes hours to start/understand how to start and set a glow engine.

1QwkSport2.5r

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