Hi

I could use some expert guidance to help me get my RCGF gas engine to start. I am a complete noob to RC engines so I've been slowly trying to work out what's going on and I've got somewhere but it still won't start.

So, the engine is an RCGF 15cc and I've been trying to get it started for the first time. I have got as far as getting it to fire enough to spin the prop and a couple of times it had enough momentum to fire a second time but that's it. I know it's been firing because i get some oil smoke out of the exhaust. I've uploaded a video to show what happens most of the time -but I can't attach the url... Occasionally it sounds a bit louder and seems to have a more powerful firing but its still not enough.

I've been adjusting different aspects to try and work out what's not right and i've worked out that:
-It fires best with 0 to 20% throttle. If it open the throttle beyond that it stops even firing so I assume its getting flooded.
-Adjusting the spark timing makes a difference. I can get it to fire best when around 30 degrees, it also fires when advanced a bit further, but it won't fire when retarded by much.
-Adjusting the idle position has no noticeable effect
-I've adjusted the low and high needle valves but they don't make a noticable difference beyond stopping any fuel (no firing) or flooding it (no firing)...
-my garage is cold (10c) so I've tried warming the cylinder block with a hot air gun. Not sure it had any impact.

I really don't know what else to try. Please can someone spot my mistake or something?

Are you "flip" starting by hand? If so, do you have access to an electric starter? Maybe somebody you know has one?

Can you see fuel being drawn through the fuel line to the carb?

Have you tried pulling the spark plug and dropping just a couple of drops in the spark plug hole, then trying to start?

Ignition battery fully charge with maybe 6v available?

The manner in which I start all my gassers is:

1) prop at 1-2 O'clock
2) FULL throttle
3) Choke ON (or full)
4) Flip; until it burps
5) Close throttle to idle position
6) Take choke off
7) Flip until it starts - usually 4-6 flips.

That works for me, but for a newbie, I'd recommend the use of a starter.

Just my technique...

Thanks for the ideas -I'll try them today.

Ahicks -yes I've been hand starting, although I have also tried using an electric drill to flip it faster but it never really sounded like it was firing when I used that. How fast does a starter spin the prop?
I also tried putting fuel in via the spark plug but that didn't help.
How much fuel do these engines use? I mean how do I know if it's pulling fuel through properly? Some fuel is definitely getting in but I don't know how to tell whether enough is getting in or too much (flooding the engine). The pulse port is doing something -as I can see a pulse down the short pipe between the base of the engine and the base of the carb.
I'm using a 5v power supply rather than a battery as it's running on a test bench -i've checked it sparks at speed (rotating prop with spark plug removed).

Tailskid, thanks for the technique - it'll be good to see if your version does the trick.

Some more questions:
-How can I tell if the engine is either starved of fuel or flooded? Is there something I should look out for to differentiate between the two?
-Is there a risk that the gaskets on the engine are leaking and I don't have a proper airtight block? Would that result in poor fuel pumping?

Thanks

A starter motor will generally spin the engine at nearly idle speed (pretty quick). A drill motor may or not be fast enough to be effective.
The amount of fuel actually used by the engine is very small. The bigger question is if the fuel pump is operational. If it's pulling fuel from the tank to the carb, you're good to go.
If the engine does not respond well to a couple of small drops of gasoline mix dropped in the spark plug hole, I would suspect your ignition system may not be functioning as designed - OR - the engine isn't being flipped/spun fast enough. Not being familiar with your power supply, I would be suspicious of that.
Flooding is obvious when pulling the plug after a few minutes of starting attempts. The internals of the plug will be soaked with fuel - very obvious.
Opposite is true of a fuel starved engine. That plug will be dry, with no signs of moisture.
Cracked components or leaking gaskets shouldn't prevent the engine from starting. They'll be more obvious when trying to get it running right.Often you will see fuel stains on the outside of the engine - which can lead you to finding items like that. Keep an eye on the engine early on.
It may pay you to seek out a replacement spark plug. NGK CM-6. The OEM plugs delivered with many engines have a spotty history. Some work great for quite a while, others are trouble right out of the box. For that reason, many are replaced with the NGK plug immediately.

Are there any clubs or other flyers I your local area? Most of them would be glad to help out a fellow pilot. And if you are hand flipping a new engine, two suggestions.
1. Get a really heavy glove so you keep your fingers all in one piece or,
2. Get a Rolling Chicken Stick so you keep your fingers in one piece.
new motors sometimes are a pain in the butt to get rolling. Kick backs are not uncommon and until it gets running (and it will) protect your hands.

In short, my balky engine routine:

See gas pump from tank to carb?
Pull plug, check for wet or dry plus test for spark.
Dry plug; dribble about 6 or 8 drops of fuel into plug hole and re-try. If it starts and quits, problem is carb or carb settings.
Plug wet; wash plug in carb cleaner or acetone, spin engine over with plug out and cylinder down. Have a cup of coffee or a beer to let things dry. Try to start again WITHOUT choke. If it floods again, problem is with carb or carb settings.

Timing should be 28-30 degrees.

A starter is really good to have for a balky engine, and a drill will work just fine.

A new brand name plug properly gapped is a two strokes best friend, second only to oil.
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AV8TOR

As Ahicks mentioned, your "power supply" is an unknown variable. An ignition only draws around 300 mAh, which even a little USB power supply should provide, but I recommend going to a 6 volt battery fully charged.

Also, in your case, warming the engine as you have can't hurt. You might also try very carefully warming the ignition box. It should NOT get hot to the touch however.

Since you are new, I will mention that even the tiniest air leak at any of the fuel line connections is a big problem.

It appears as though you have an analytical mindset and patience. Keep at it, you'll win. You're going to love gassers in the end. Welcome to the forum. There's a wealth of knowledge and experience here.


AV8TOR

Thanks for the advice!
I managed to get it to run for about 10secs using Tailspin's method -I realised I'd left the fuel shutoff valve closed.. grr. Couldn't repeat that though and gave up when my arm got tired.
I've ordered a starter to give that a go. I'm guessing its probably a carb setting so hopefully with the starter I'll be bale to adjust it slowly till its working. I have an NGK spark plug too so I'll swap that one it.

Do change the plug and go back to the factory settings for the carb. Gently turn the high and low speed in until they stop do not force. As per manual low speed open 1 1/4 turns high speed 1 3/4 turns. Follow manual start instructions with new plug. Those off shore plugs are hit and miss at best.

Dennis

Fuel shutoff valve? Most airplanes don’t use any kind if shutoff valve.

Have any luck getting that puppy running yet?

Tailskid's (not Tailspin) method is one that's used for most every gas airplane engine... even with a starter. You engage the choke, flip the engine(or hit it with the starter).. until it pops/fires(it won't start with while choked, it will just fire a time or two).. Once it pops, disengage the choke and flip it. It should start.. but at this point who knows.

What the heck shut-off valve are you talking about. Therein might lie a problem too.. if you're inexperienced and there's components in there none of us are using, how did it get there? LOL... Did someone use a bunch of inexperience and throw a valve in there? It's not a motorcycle with a fuel shut off on the tank. There's absolutely no shut off needed of any sort...You drain the fuel at the end of the day is how you shut it off... haha.. Good luck with it.