[JohnM]

John: I own an O.S. .55 ax as well. It has had about 400 flights and works perfectly, In fact, better than new! I also know that you are a very experienced flyer but something is fishy here. What can go wrong? Either the engine is not getting fuel or your glow plug is acting up. I know you have replaced everything. Perhaps your engine is simply worn out! It does happen! For my two cents - I go along with those who believe you have fuel line problem in your tank. I have had similar problems and it always seems my fuel lug has come off in the tank. ( I know you have checked this). . . Good luck - John M.

[pianodude]

hey john. nice to see you last week at skycraft! i replaced the stopper with a two line(pressure,carb) instead of the three line that is on there now. i will try it tomorrow and see, but i really still don't know what could have gone wrong so suddenly. after each deadstick there is still fuel in the line to the carb with no bubbles. i replaced the glow plug with a brand new one. all the bolts are tight and the needles ssem to be right where they ought to be. i am quickly running out of ideas

[AJCoholic]

Originally Posted by pianodude

i have been flying my revolver with this engine all season(probably 8-10 jugs through it). hasn't so much as hicupped since new. last week four deadsticks in a row after flying for exactly five minutes. replaced the glow plug, same problem. took out the tank, replaced all lines inside and out and pressure tested ok. same result today. hi end and low end seem to be fine. i haven't needed to change the hi end more than a few clicks either way since new. any thoughts or suggestions? john

Have you tried a different jug of fuel? Just thinking..

AJC

[pianodude]

hey andrew. come to think of it, it was a brand new jug out of a fresh case, but i am already through that jug and onto another. i will break out another jug tomorrow and see what happens.. stay tuned folks! john

[Gooseman240]

That should be very intresting if it is the fuel. Suck to, do they refund?

Possible the whole lot is bad since all jugs would most likley be from the same batch packaged in a case perhaps.... so hope it is not that. Try getting a refund on gasoline :P

[mjws]

I know a bunch of people that really like an OS F on these. The extra platinum (stronger reaction) supposedly cures the random dead sticks with them. The 'five minutes' every time really sounds like a leak/fuel level/pressure type problem. But if I'd try the other plug for fun as well. Will it quit on the bench?

Mike

[mdscientist61]

Hello John,

You might possible have a piece of grit stuck in your
needle valve assembly. It makes your mixture go all over
the place as the grit moves around the end of the needle
valve inside the assembly. This is how I flush out my
needle valve.

1) disconnect the tube that goes from the tank to the
needle valve and connect the tube from your fuel jug
directly into the needle valve.

2) completely remove the needle valve. (count out the number of turns for its mixture setting first)

4) stand back so the fuel does not squirt on you and "blip" your fuel pump. A little stream of fuel will squirt out where the needle valve used to be. The first pathway is flushed.

5) Leave the pump connected to the needle valve assembly. Now look at the needle valve and wipe off any grit from the needle. Now re-insert the needle valve but only put it in enough to barely make the contact with the O-ring. Open your throttle wide open. Blip the pump again. Now the fuel will squirt up in the carb. The second path is flushed. Now put your needle valve back to its correct mixture setting.

6) As a side note, I had one engine where the was some grit trapped in the spray bar assembly so I had to take the barrel out to remove it.

7) Now be advised that your engine is really flooded and you have to be careful not to get hydraulic lock in your cylinder. (I ruined a perfetly good engine like that once). So you have to pick up your airplane and hold it sideways and upside down or whatever and flip your prop by hand until you get the excess fuel out of the crankcase, over the piston, then out of the muffler and away from where it can cause hydraulic lock. (Note if you still have the baffle in your muffler it will inhibit the fuel draining out and the execess fuel can flow from the muffler back into the piston)

9) Now that any risk of hydraulic lock has been removed, you can start your engine and re-tune your mixture and off you go.

10) you might have to repeat this procedure maybe three times, once after each of your three next flights, to get it totally clean.

Another thing is that maybe your needle valve O-ring is leaking air. You can try replacing the O-ring too.

[Gooseman240]

Good advice MD!

[pianodude]

hey mad scientist. a great idea and i will definitely do that next time as that was the only thing i didn't try, but WOOHOO! five 15 minute flights today with absolutely no trouble. every possible aerobatic/throttle combination i could think of. must have been a leak in the old stopper, but i will never really know. thank you gentlemen so much for the good advice because even though i have have been doing this a long time i love the fact that there are still many things to learn. cheers and happy flying, john.