Needle Valve Initial Settings?
 

I picked up a couple of used trainers. I did not get any paperwork with either one.
One starts just fine, the other starts and then dies (I am priming the carb to get it started)
I may have a bad glow plug but the other thing I am not sure about is the initial needle valve settings.
It's a Tower Hobbies .46 Ball Bearing ABC motor.
Tower does have have a link to a manual on this motor (or I missed it).
Anyone?

RE: Needle Valve Initial Settings?
 

From Tower's website

Ken

RE: Needle Valve Initial Settings?
 

OK, thanks. I started with 1 turn out and around 1/3 throttle or a little more. It started about 1 1/2 or 2 turns out but it seems to burn just the fuelI primed it with, maybe a little more. Adjusting it seemed to make little difference.
I will pick up some more glow plugs, I will need them anyway for the other one.
I will also attempt to determine if fuel is flowing to the carb or not.

RE: Needle Valve Initial Settings?
 

Good plan for the future, but if your engine runs the prime out, something is firing that fuel, and good probability it's the plug. So it's a better than even bet the plug isn't why it's only running out the prime. You really should pull the plug and look at the element no matter what. Look to see if the element is mashed down or to one side. If it's clear of the sides and doesn't look broken, test it while it's out. Connect the battery and see if it gives a strong glow. If it passes all the checks, put it back. Tighten firm, but don't go overboard.


You can easily do that by finger choking. Put your thumb over the opening in the carb to plug it tightly and turn the prop a revolution by hand. Watch the delivery tubing while you do it. It should only take a couple of turns until fuel shows up being pulled to the carb. Used engines sometimes have crud in the tank, fuel tubing, or inside the needle valve. Back pumping sometimes pushes the blockage back into the tank. Try to fill the tank from the engine's fuel line. It will at least show you how clear the path is from the carb back. While the line if off the carb, try to pump right into the carb. If it seems blocked, pull the needle completely out and pump again.

RE: Needle Valve Initial Settings?
 

+1

The above is a good check, but it should be mentioned that you do this without the plug heat on it ;). I have to admit that I've seen some people over the years do just that with the heat on.

RE: Needle Valve Initial Settings?
 

OK and thanks
I figured it would not hurt to have the glow plugs anyway for spares. I didn't really think it was the problem.
I remember pulling the needles out years ago and blowing back through to clean.
I had forgot about the finger choking~man does that take me back. I had forgotten
And yes, I know to have the heat off.
I still have some scars on my fingers from the old days of batteries and engines kicking back when we all started without the aid of an electric starter. They are faded as are the memories.

RE: Needle Valve Initial Settings?
 

If the engine kicks over and starts for a brief interval, then dies AND you have the needles set as per the factory specs... then choose any of the following

1 - The carb is not getting fuel or enough fuel.
2 - The tank is not getting muffler pressure
3 - There is an obstruction somewhere ( see 1 )
4 - There is a leak somewhere ( see 1 )
5 - Your lines may be too long
6 - You may have your lines reversed
7 - The clunk line may have fallen off within the fuel tank.

Open the needles about 1/4 - 1/2 turn more than factory specs to start with.

RE: Needle Valve Initial Settings?
 

OK, I examined the lines and the needle valve and found no problem. It was still having problems getting fuel.
I then noted that the tank seemed to be out of position (too far back or a really large tank)and found it was not fastened down or held in place. The stopper had come out of the tank and the fuel pickup was intermittent as it was barely still in the tank.
I sure am glad that I only put a little fuel in the tank otherwise I would have had a mess on my hands.
I hooked the engine up toanother tank outside of the plane and fired the motor and it runs fine.
I will have to do some repairs but it appears when the guy put this one together he failed to secure the tank.
The scary thing is that he is a commercial pilot completing his master's degree at Embry Riddle Aeronautical.
I certainly hope he is better at flying them that he was building models and following instructions! http://www.rcuniverse.com/forum/js/f...wink_smile.gif