ORIGINAL: tilsonm
HELP! It's driving me crazy!
New OS 61 FX. Has about 1/2 gallon of very irregular run time. Motor now runs only with glow igniter attached. It will run about 7 seconds at 1/4 throttle with the igniter off.
I have done the following in separate steps so as not to confuse the result:
1. Leaned the engire to the point that it wouldn't run, the backed off 1/4 turn.
2. Changed Glow Plugs
3. Changed Glow Plug ingniters
4. Changed mufflers from Pitts to standard and back
5. Changed gas tank and fuel linies.
6. Checked Head-Bolts and all other fittings
7. Changed props
8. Tripple checked needle valve for dirt etc.
9. Tried with and with/out a fuel filter.
I'm running 10% Nitro mixture. When it is running, it seems to run OK at full throttle and will idle ( a little bit high ). It does not transition quickly from idle to full very smoothly. A little hesitation or total stop depending on needle settting.
Thanks in advance.
Mike
Did you adjust or check your mid-range?
Many people don't know about this technique and they usually have engine problems because of it. Also if it only has a 1/2 gallon of fuel, it doesn't sound like you've properly broken in your engine if it is that new. No matter what the manufacture says- "Break in youre Engine!"
Normally we have to keep turning off the motor everytime we make a turn on the low end, and every time I did that, we have to re-adjust the top end needle. It can be a pain!
But I found a way that was taught to me by one of the Ol'times at my club on how to accurately find and set your mid-range, without all the calisthenics.
First I usually crank the engine at 100% then bring it down to 50% and take a long wire hanger, straighten it out and beat one end with a hammer and file the tip straight- and use it to adjust your low end while your engine is running at 50%. It will go up in RPM quite a bit and if it starts to decrease in RPM when you are tightening the low end, then you went too far. Back off on it! As soon as you have that nice smooth sound, back off 1/8th of a turn. Now Throttle up and re-adjust your high end.
What I just explained to you is how to adjust your low and mid-range. With a straight coat hanger, and by making a thin screw driver out of it, if you slip your wire will hit the prop and not your hand and you can get a more accurate setting besides all that. While making your adjustments keep your glow igniter on just incase she wants to quit on you while you are making adjusments.
I'm sure it will work for you. Most glow 2- stroke and 4- stroke engines run on the same principle. From my experience I found that O.S. is one of the easier engines to adjust. Saito second. JMHO
Try it, I think you will solve most if not all your issues unless there is something wrong mechanically.
Pete