Engine Dies at Idle when Glo Starter is Removed

by Pieter
(Nigel)

When I remove the glow start from my 40 OZ MAX FP engine it dies.

If i open it to full throttle it runs nicely without the glo starter. As soon as I bring the revs down to idling it dies.

It idles perfect with the glow starter attached.

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Engine Dies at Idle when Glo Starter is Removed
by: Anonymous

You need to tune your low end needle valve.

Does it die on anything below half revs or only when it is at idle?

If so, the idle may be set too low.

Have you tried a new glow plug?

What angle is the motor mounted, ie is it upside down?

Are you giving the engine plenty of time to warm up?

Is your fuel OK? Does other planes run OD on the same fuel?

So many thing we need to know to give a good answer.

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idleing problems
by: Pieter

On half revs it runs fine.

No I have not treed a new glow plug yet. I'm not sure which number glow plug to use.

The motor is mounted straight up. I gave the motor two minutes to heat up. It starts with the first turn.

I am using brand new 10% nitro plane fuel, it's one week old now.

When I take the glo starter off, the motor dies immediately.

Do you think I have to get another engine. I am new to all of this.

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Engine Dies at Idle when Glo Starter is Removed
by: Anonymous

The engine will be OH. It's all in the tuning and glow plugs.

It starts, so you will get tuned right eventually.

Do you have a taco meter / rev counter? If not, you should get one.

Get a length of fuel tube put it on the carb. As you got it running a little, turn the high end needle in to close it right up COUNTING THE NUMBER OF TURNS IT TAKES TO CLOSE IT .

Then open the high needle five turns and put a sowing pin in the top of carb and close the throttle to just hold the pin in place.

You blow down the fuel tube at the same time turn the low end screw so you can just hear a little air coming out.

Then replace fuel tube from the tank and try starting the engine. Adjust the high end needle this will give a good starting point.

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Is your fuel fresh?
by: Michael from Oz

G;day

The OS FP Series of engines have an air bleed carby. First thing to check is that the air bleed screw (small screw on one side of the carby which partially blocks a small hole in the front) is about half way blocking the hole.

But ... there is another simpler problem that will make engines idle poorly. Stale fuel. If your fuel has picked up water (and all fuel does), then the engine will not idle.

Air bleed carbys are a compromise and never give the best possible idle so be prepared for this.

Also, if the revs drop when the plug driver is removed, the plug is often too cold. Try a hotter plug.

The Enya #3 is a great plug for slightly difficult engines. They are around on eBay. The OS #3 is also suitable for low nitro.

You did not say what sort of fuel you are using. This engine should have a fuel with a fair percentage of castor oil in it as it is a plain bearing engine (bronze bush). 10% nitro is about right for these and at least 20% oil.

To tune the air bleed, you have to open the hole to make the idle mixture leaner and close it to make it richer. Sometimes, the hole gets blocked with fuel residue and this will stop the engine idling as no air can get in at low throttle openings.

Hope this helps a bit.

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Low Idle
by: Factorywriggs

When i adjust an engines fuel requirement, firstly you will need to establish
1/the correct Prop size
2/Fuel type and strength. ie 5%-10%-15%
3/suitable Glow Plug that suites the nitro content, you will not need to use a hot plug with high nitro content unless engine is tuned for competition.

When you have started the engine, adjust the main fuel feed needle to achieve the highest RPM.
drop down to idle and listen to the engine, does the RPM begin to drop and sound flooded.
If yes! then this is the low end needle being set too rich and allowing too much fuel into the engine than the engine requires to idle.What is happening, is that the excess fuel is trying to extinguish the ignited glow of the plugs coil , like throwing a bucket of water over it. If it goes out, then the engine will stop.
Re tune or turn in the low needle half a turn at a time until the engine idles smoothly and will pick up from idle to full revs instantly, but remember to re tweak the top end main needle each time you do this as it progressively shuts off the original main needle setting that you had before the adjustments.
This method only applies to back to back needles like most 2 smokers and saito four strokes.

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