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  1. #1

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    cox 049 will not start

    The owner/good friend at my lhs gave me a 049 to bolt up on my 1.5 meter sailplane. It is used an he was nice enough to give it to me for nothing. I took the motor completely apart an cleaned everything properly. I also replaced the little fuel hose in the tank an placed the spring back into the tubing. I made sure to replace the gasket properly as well which mounts to the tank an back of crank case. I tried for a solid hour to get this thing started an nothing. I have glow, Im only using 1 D size battery (didn't want to go overkill with the power panel), used 20% nitro as well. Tried starting with the needle 3 turns and 2 1/2 turns out. I can only get a 5 second sputter when I prime the exhaust with fuel. Am I missing something? Been in the hobby for many year an im dumb founded by a 1/2a size motor!

  2. #2

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    RE: cox 049 will not start

    How about the reed valve? When you took it apart, could it have gone in backwards?

    What percentage of nitro are you using? I think that 25% might be a good starting place for that engine.

    Just my $.02

    Bob
    Club Saito #61 Cub Brotherhood #107
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  3. #3

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    RE: cox 049 will not start

    You can put the reed in backwards? I thought it was flat? An then you just replace the little circlip holding it in place.

  4. #4

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    RE: cox 049 will not start

    Sometimes, after a while, they take a 'set' and won't seal. Place it on a flat surface. If itisn't flat, place the four 'legs' against the fuel tank.
    \
    How about the nitro in your fuel? Are you using half-A fuel? Are you sure that the glow is lit? You should be able to look inside the exhaust port (in the shade at least) and see the reflection from the glow plug.

    Is it popping at all? Try a squirt of lighter fluid in the exhaust port if you happen to have some. Have you been priming the engine using glow fuel in the exhaust port??

    Just a couple of thoughts,

    Bob
    Club Saito #61 Cub Brotherhood #107
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  5. #5

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    RE: cox 049 will not start


    ORIGINAL: N1EDM

    Sometimes, after a while, they take a 'set' and won't seal. Place it on a flat surface. If itisn't flat, place the four 'legs' against the fuel tank.
    \
    How about the nitro in your fuel? Are you using half-A fuel? Are you sure that the glow is lit? You should be able to look inside the exhaust port (in the shade at least) and see the reflection from the glow plug.

    Is it popping at all? Try a squirt of lighter fluid in the exhaust port if you happen to have some. Have you been priming the engine using glow fuel in the exhaust port??

    Just a couple of thoughts,

    Bob
    Bob,

    I deff have glow because when I squirt nitro in the ports to prime I can hear it sizzle an see it smoke. Yes it is popping when I turn it over. No im noting using 1/2 A fuel. I don't even know where to purchase that. Would 30% heli fuel work because that I do have.

  6. #6

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    RE: cox 049 will not start

    Your engine will run on 20%. The oil content is more important and should be in the range of 18% to 20% with the majority being castor.

    It sounds like your engine is running on prime only my inclination is that your venturi/NV is likely clogged with congealed castor and is blocking fuel flow. When you replaced the fuel pickup tube, did you use the same tube or new fuel tubing. Generally, we usually toss the old tube because is has hardened and will allow the engine to suck air where it attached to the fuel nipple on the backplate.

    Remove the needle and flush the NV seat well with fuel. You can also add fuel to the air inlet screen on the backplate. To check the reed for seating, remove the tank, wipe the reed housing clean and place your mouth over the reed housing. By alternately sucking and blowing air, you can determine if the reed is seating. You should be able to easily suck air past the reed, but when blowing lightly, the reed should seat and not allow air to pass. If you have a syringe or fuel bulb, pumping fuel under pressure into the fuel nipple will help clear any blockage around the NV seat.
    the "other" andrew
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  7. #7
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    RE: cox 049 will not start

    Be a bit careful with the 30% heli fuel. Does it have any castor in the lube content? I'd be wary if it's 100% synthetic. But I don't want to hijack the thread into a castor vs synth discussion. That's been done many times before.
    I've run .049s on 15% nitro, 20% oil (50/50 castor/synthetic) and they run just fine.
    Are you hand starting or using the spring?
    I use an electric starter (carefully) and they go every time.

  8. #8

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    RE: cox 049 will not start

    These engines will run fine on 15% nitro so the type of fuel is NOT the problem. The problem IS that fuel is NOT getting to the combustion chamber.

    So starting at the tank pick up you will need to trace the flow of fuel into the engine step by step. Remove the pickup tube and blow into it, does air flow? Next attach a long piece of fuel tubing to the fuel pick up nipple inside the tank, blow into it, does air flow with the needle 2 turns out or so? Take the same length of fuel tubing and attach to the venturi tube inside the tank that goes to the reed, blow into it and then suck on it, does the reed allow airflow and then stop airflow? Make sure all of the tank vents are clear too.

    Be sure to check the intake screen for obstruction. If there is blockage in the needle valve it can be cleared by removing the needle and gently inserting a fine piece of music wire into it to clear the obstruction, you should be able to pass the wire all the way through so you can see it through the intake screen. The music wire will need to be about .032 or smaller in diameter, a fine dressmakers pin might work, do not force it or you will damage the seat.

    Re-assemble the engine and hopefully it will start.
    I fly aircraft at the leading edge of trailing edge technology!

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    RE: cox 049 will not start

    If you have an engine with a 'G' clip style reed retainer, you might also want to check if you put it in backwards. These clips are not flat and they need to stand up away from the reed, or they will pin it to the reed seat and prevent the fuel/air mixture from entering the crankcase.

    If it's not a 'G' style clip, then follow the others' suggestions about clearing the fuel supply route.

    Good luck and don't give up.
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    RE: cox 049 will not start

    There is also a very tiny gasket at the center of the backplate where it connects with the tube leading to the needle valve. If that is lost or damaged you will not get any fuel draw. You can make a workable one from a very thin slice of small silicone fuel line. I have seen these missed in so many engines that I am have lost count.

  11. #11
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    RE: cox 049 will not start

    Bernie sells the 'O' ring by the 10 pack I believe
    Real Airplanes have Round Engines and Two Wings.

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    RE: cox 049 will not start

    I've run .049's on every fuel I have and never had a problem because of fuel. Different fuels give me different RPMs but they always ran. Just because you hear "sizzle" doesn't mean the plug is getting enough juice.

    .049 plugs are just like regular plugs. You can use your power panel to power it and it will be ok. The first thing I would do is try using the power panel. If it still won't start I would take it back apart and make sure your tube didn't fall off the backplate.

    Also, I didn't notice if you said the engine kicks or not. If it's kicking then you probably are getting enough power to the plug. If it isn't kicking at all then I would bet money it's not getting enough juice.
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  13. #13
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    RE: cox 049 will not start

    Could be pluged with dried caster oil in the fuel jets or needle valve. Very hard to clean. Try soaking back plate in lacquer thinner about at lease a day and blow out with compressed air.
    Mike Burg

  14. #14
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    RE: cox 049 will not start

    ORIGINAL: skaliwag Bernie sells the 'O' ring by the 10 pack I believe
    In a pinch, I've used a very sharp Exacto knife or razor blade and cut a thin sliver of small silicone fuel line for a tank venturi gasket.
    George Hostler
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    RE: cox 049 will not start


    ORIGINAL: GallopingGhostler

    ORIGINAL: skaliwag Bernie sells the 'O' ring by the 10 pack I believe
    In a pinch, I've used a very sharp Exacto knife or razor blade and cut a thin sliver of small silicone fuel line for a tank venturi gasket.
    If you have the skill or patience that's a good way. A foolproof way is to stretch a piece of fuel line over a dowel. Leave enough dowel uncovered that you can chuck it into a drill or drill press (better). Then hold your hand steady with an X-Acto and cut a bit to give a clean end. Make another cut just a sliver. Works like a charm.

    Sort of related, I also found that I can cut 1-1/2" pvc into as thin as 1/32" rings using a table saw with a starter block clamped to the fence and a cut-off sled. The rings were very clean.
    Work is what I do for the love of it. A job is how I pay for it.
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  16. #16
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    RE: cox 049 will not start

    I'm sure there are ways to improve, CafeenMan, and you certainly have done that by amplifying the thinness of the tubing prior to cutting, as well as get a more precise cut. A reflection of my prior martial arts days, my cuts were with Ninja precision, LOL.
    George Hostler
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    RE: cox 049 will not start

    Ah yes... the Ninja Builder!!! The greatest level of craftsmanship attainable. I hear the ninja builder's sharpened fingernails can strip balsa sticks with an accuracy of less than 0.001".
    Work is what I do for the love of it. A job is how I pay for it.
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  18. #18
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    RE: cox 049 will not start

    Of course! I practice the art of invisibility! Crash damage vanish without a trace!

    (May be a slight trace, LOL!) [8D]
    George Hostler
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  19. #19

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    RE: cox 049 will not start

    I think it has been said but the G clip has to be installed correctly and the reed must rotate under the clip as well as it center of the reed move back and forth to allow air and fuel movement. The center of the G is raised when lying on a flat surface such a piece of glass. If the reed wont rotate and move it will not run.

  20. #20

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    RE: cox 049 will not start

    I it's burning off the prime it's a fuel issue.

    1. Use 2 D cells to bump up the current not volts current.

    2. Try 4 to 5 turns open on the needle to get her running.

    3. If this dosent work then check the G- clip. The reed needs to be able to move under the clip (open and close the oraface it covers) if the clip is installed backwards the reed will not move. Also check the fuel pick up and seal at the nipple as previous respondes have suggested.

    rrragman
    \"Half a bee, philosophically, must ipso facto half not be. But half the bee has got to be, vis-*-vis its entity - d\'\'you see?

  21. #21
    GallopingGhostler's Avatar
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    Got to agree there rrragmanliam. I have a .049 Black Widow that was mounted to a Sterling Beginners Fokker D-Vii, given to me in the mid 1980's. Recently I attempted to fire up the engine, wouldn't run. The needle valve assembly portion of the tank back was gunked up. After soaking in solvent overnight got rid of the Castor oil clot. Checked reed valve for freedom of movement and open venturi. Now it fires up readily.
    George Hostler
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  22. #22

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    Also place a small piece of small fuel line on the needle to seal it from leaking air around the threads. And what size (Dia. pitch) prop are you useing. As these engines can be very unhappy with the wrong prop.And do you have a head gasket (s) ?

  23. #23
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    Will these run 4-5 turns open on the needle?
    I've never had to go more than 3 to get a .049GB running and not sure it would stay running or start at 5 out.

  24. #24
    GallopingGhostler's Avatar
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    My son's field find that I cleaned up the exterior, a mid 1960's Babe Bee required 4 turns to run. Usually it is less than that for others. A piece of fuel line might work for leaks on a venturi back that has some threaded nipple extension. The tanked engines did not have that. But then the Cox made ones were tight enough that it was never a problem.

    I really like the old Cox 290 engine backs, because they came with really fine threaded needle valves, a real prize. These were the ones molded in red that were rectangular in shape. Goldberg used to make a nylon engine bracket that allowed these to be bolted into an aftermarket or kit built airplane, since they had no provision for mounting holes.
    George Hostler
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    And we know love by this, that He laid down His life for us, and we ought to lay down our lives for the brethren. 1 John 3:16

  25. #25

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    Quote Originally Posted by xplayer930 View Post
    The owner/good friend at my lhs gave me a 049 to bolt up on my 1.5 meter sailplane. It is used an he was nice enough to give it to me for nothing. I took the motor completely apart an cleaned everything properly. I also replaced the little fuel hose in the tank an placed the spring back into the tubing. I made sure to replace the gasket properly as well which mounts to the tank an back of crank case. I tried for a solid hour to get this thing started an nothing. I have glow, Im only using 1 D size battery (didn't want to go overkill with the power panel), used 20% nitro as well. Tried starting with the needle 3 turns and 2 1/2 turns out. I can only get a 5 second sputter when I prime the exhaust with fuel. Am I missing something? Been in the hobby for many year an im dumb founded by a 1/2a size motor!
    While you are checking all the excellent things that have been suggested, pull the fuel tubing off the backplate and with the needle turned 3-4 turns out, squirt some fuel into the fuel intake on the backplate. That will eliminate castor blockage to the needle. I believe everything else has been covered.

    Good luck and keep us posted of your progress.

    George


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