Surestart with carburator mod bench test

Hi, what do you mean to check carb from the needle? You mean I should also adjust needle when at "idle"?

Raise the fuel tank as I show in the capture of your video.
Close the entire needle and open it about 3 1/2 turns.
Start the engine.
Keep the air valve fully open.
Once running, close the needle until reaching the maximum rpm.
Open the discharge needle just a few clicks.
Begin to close the air valve.
We see what happens.

Test again today as you said, raised the tank, run at about 3 turns open, lean it for max rpm and open up again the needle just a few clicks. When i closed the air valve and got about 2000rpm lower and then dies. I am running a 12% nitro fuel if that matters. (there is no difference from fully open to 3/4 closed of the airvalve). Also when you referring to ''discharge needle'' you mean the needle right? There is only one needle in my setup.

Thomas

I like your starter
were did you get it

Its a nice compact little starter that i design it my self and then 3d printed it. I have plans of selling (just the case) without the 540 motor, battery etc to anyone interested but i have to check the final cost as well as shipping charges before i set the final price. So stay tuned for this one.

Thomas

you you make it a complete usable kit
I am interested

Thank you, i will let everyone know when ready, but not sure for a full kit yet.

These are not RC-carbs but merely a a cold start choke, so they will reduce rpm mainly by making the engine run richer (plus restricting the air flow), there are lots of threads on this earlier on this forum.

What prop size are you using?
It seems like the prop load is too large, this makes the top rpm low and the needle setting has to be rich already at the top rpm. So then with the choke applied it easily/quickly goes too rich and dies.

With a smaller prop load you will be able to lean out the engine further and get a higher top rpm. The engine will then likely tolerate more of the choke, thus producing a lower lowest rpm, before it is choked too much and stops.

More nitro in the fuel also tends to provide a broader needle setting and thus a higher tolerance to the choke, so that might be worth testing too.

Prop is 6x3 but I can test a 5x4 that I have or a 3 blade 5x3 I might test it tomorrow again with the smaller prop. Is there any standard size for this engines?

Ok, buddy, if you've made those corrections, your glow plug may "go off" when you start to close the air valve.
I have noticed that some glow plugs are hotter than others, although they are all sold equally.
Maybe your glow plug is "cold" or that it is with some wear and does not maintain the necessary incandescence to maintain the explosion.
You can do two things and try:
1) Change your glow plug for another and do the test.
2) Add a fuel with 20% nitro.
If that doesn't help, then there is another problem that I can't detect.

Here I make a very short video, since my neighbors sleep !! ... ....
Cox .049
Regulator - air valve
Propeller 6x4
RPM: 8000/15000
Nitro: 20%
Glow Plug: (not original) (Merlin type)

Remember: that it IS NOT A CARBURETOR, the air valve is not instantaneous, it has a slowdown when accelerating and decelerating the engine.

Fuel might be the answer although I want to try one of this heads, what type of plug it is, I might convert one of my heads. Nice run by the way. I have run my neighbors nuts the last couple of days I guess

Do not modify your glow plug, try another one if you have one and go for nitro at 20%.
In any case, you can see to get this type of glow plug that this engine has and that I leave a link for you to guide.
http://www.exmodelengines.com/product.php?productid=17871&cat=279&page=1