Needle Valve settings...
 

Just this last summer, I cleaned up an old gummy engine and got it running... kinda. I could get the engine started but it would die soon after. I assume (so I hope I don't make an ***** outta me) that it's a good chance that its the gas as it is many years old or the tank needs cleaned out because it has set for far too long with no use. I will fix these things before I try again, but I think I got lucky starting it cause I have absolutely no idea where to have the needle valve set. Are there any tricks on where to start out or any advice on how to adjust it? This info will be put away until the weather is nicer for me to try again, but will definitely be used.

I just wanted to say thank you to you guys for helping me out in my last post. I didn't think I would get that much help so quickly. I appreciate it!

RE: Needle Valve settings...
 

If you are serious about getting it to run things must be in good order. Fresh gas, good fuel lines, good glow pug. If this is a 4 stroke you want to check that the valves atre both working freely. Turn needle valve all the way in and then back out about e turns. That should be a good place to start.

RE: Needle Valve settings...
 

It would help us a lot to know what engine it is. Definitely change out the gas for new stuff, clean out the tank and replace the lines.

Dr.1

RE: Needle Valve settings...
 

We can't really tell you much without knowing the engine. I would throw the gas right out, two year old gas isn't going to run good in any engine, new or old.

Good luck!,
Austin

RE: Needle Valve settings...
 

It is a 2 stroke, 40cc

RE: Needle Valve settings...
 

A 40cc engine is huge and uses a 18-10 prop. It runs on gasoline. It would be a chainsaw type engine. The plane would have a 8 foot wing span.

Do you mean .40 ci two stroke and glow fuel? What brand is it and what letters are on the engine

RE: Needle Valve settings...
 

You're right! lol .40 that uses glow fuel. It is manufactured by OS... several engines that I have are all OS.

RE: Needle Valve settings...
 

Most glow engines will start at similar needle settings. All the OS engines I have (all recent vintages) will start rich at 2 turns out on the main needle. For now don't adjust the idle needle.

As others have stated, start with known good fuel and a known good plug. New fuel lines inside and outside the tank are also a good plan. A .40 should probably be run in with a 10x6 prop.

Fill the tank, and hook up the fuel lines to the engine. Open the high speed needle about 2 turns from gently closed. Open the throttle full. Be sure no glow starter is connected yet. With a thumb over the carb, turn the prop over to draw fuel to the carb. Once fuel has reached the carb, turn the prop 2 or 3 more times to prime the engine. Remove your thumb from the carb and flip the prop briskly a half dozen times to move the fuel up into the cylinder.

Close the throttle to about 1/4 open or less. Now connect the glow starter. Use your electric starter or a chicken stick to start the engine. It should start in a few flips and begin running. If it starts backwards, just close the throttle and start again at the beginning of this paragraph.

Once the engine starts, move behind it (out of harms way!) and slowly (take 2-3 seconds) advance the throttle to wide open. The engine is probably running a bit rough now, in a "4 stroke" mode. Sounds a bit slow and labouring, this is good for just now. Disconnect the glow driver. Leaving the throttle wide open, slowly close the high speed needle. The engine speed will increase for a while, smoothing out into a pure 2-stroke rythme, and then plateau. If you go too far, it will begin to quit, back up a bit quickly! When you find the plateau (where the RPM's peak), open the high speed needle a click or 2 until the engine just slows a hair from peak rpm's. This is where it should be adjusted for flying.

Now close the throttle to an idling RPM. Should idle at less than 3000rpm reliably for minutes on end. If the idle slowly slows, tending towards quitting, but picks up if you pinch the fuel line a few seconds, you'll need to close the idle needle a bit (assuming a 2 needle carb.... If it's an air bleed carb, you'll open the air bleed a bit....). If the engine quits immediately when the fuel line is pinched, it's idling too lean. Ideally, you should be able to idle a minute or so, and when you pinch the fuel line, the rpms should pick up for a second or 2 and then the engine dies. If this is the case, your engine should be good now, with a good top end, reliable idle and reasonably clean transition from idle to giv'er.

Quit on throttle up = lean idle
Stumble on throttle up = rich idle

Good luck!

J

RE: Needle Valve settings...
 

Wow, very nice... using your method Jburry, the engine started in my head without fail! lol I can't wait to go out and try this on my plane. Thank you for such detailed instructions!!!!