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Author Topic: magnum pro 25 wont run properly  (Read 2447 times)

ron young

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magnum pro 25 wont run properly
« on: October 02, 2013, 05:29:57 PM »
      Well at Brodaks this year I bought a ringmaster complete with this engine have not been able to get it to run,the first pass with the plane the engine quit and had to land inverted it bent the needle a little but would run put up another flight and motor mid way coughed and went to maybe half power then at the end of that run picked back up.So went a couple times and coudnt get it to run period,today I got the ventury hole aligned with the needle valve?sorry the terminology isn't coming to mind anyway today it ran but only one speed with not enough power you can turn the needle valve probably 2 turns with no difference.i believe all is stock don't know if engine is new or not it looks to me like little if any use.i am using richs brew 10% nitro 11/11 castor syn.will these engines run .I do have b25 and la25 but would have to modify mounts to make holes right prefer not to proly long winded sorry any thoughts or suggestions will be appreciated
Ron
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ron young

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Re: magnum pro 25 wont run properly
« Reply #1 on: October 03, 2013, 03:01:21 PM »
Quote from: ron young on October 02, 2013, 05:29:57 PM
      Well at Brodaks this year I bought a ringmaster complete with this engine have not been able to get it to run,the first pass with the plane the engine quit and had to land inverted it bent the needle a little but would run put up another flight and motor mid way coughed and went to maybe half power then at the end of that run picked back up.So went a couple times and coudnt get it to run period,today I got the ventury hole aligned with the needle valve?sorry the terminology isn't coming to mind anyway today it ran but only one speed with not enough power you can turn the needle valve probably 2 turns with no difference.i believe all is stock don't know if engine is new or not it looks to me like little if any use.i am using richs brew 10% nitro 11/11 castor syn.will these engines run .I do have b25 and la25 but would have to modify mounts to make holes right prefer not to proly long winded sorry any thoughts or suggestions will be appreciated
Ron
:(
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ChrisSarnowski

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Re: magnum pro 25 wont run properly
« Reply #2 on: October 03, 2013, 03:32:57 PM »
Hi Ron,

One thought is that you have an air leak some where if the engine is not responsive to the needle valve adjustment.

Check to make sure that your engine's back plate screws are tight, and also that there is a gasket on the backplate (probably clear mylar on that engine).

Test/inspect the fuel line for leaking (pull it off, pinch one end, try to blow through it). Might just want to replace it anyway. Also check that fuel filter (if using one) is not leaky.

What kind of needle valve are you using? An OS type needle valve can leak on threads. I usually put a piece of fuel line on the threaded shaft so it reduces leaking.

Pressure test your fuel tank (remove tank from model, cap off vents, try to push air into fuel feed line with syringe). Easy to see leak bubbles if you put it into bowl of water.

Those are some easy things to check. Good luck!

-Chris
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Online Brett Buck

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Re: magnum pro 25 wont run properly
« Reply #3 on: October 03, 2013, 06:08:43 PM »
Quote from: ron young on October 02, 2013, 05:29:57 PM
      Well at Brodaks this year I bought a ringmaster complete with this engine have not been able to get it to run,the first pass with the plane the engine quit and had to land inverted it bent the needle a little but would run put up another flight and motor mid way coughed and went to maybe half power then at the end of that run picked back up.So went a couple times and coudnt get it to run period,today I got the ventury hole aligned with the needle valve?sorry the terminology isn't coming to mind anyway today it ran but only one speed with not enough power you can turn the needle valve probably 2 turns with no difference.i believe all is stock don't know if engine is new or not it looks to me like little if any use.i am using richs brew 10% nitro 11/11 castor syn.will these engines run .I do have b25 and la25 but would have to modify mounts to make holes right prefer not to proly long winded sorry any thoughts or suggestions will be appreciated
Ron

   It's really hard to understand what you wrote here, but yes, the engine will run reliably if it is fed fuel and air, and has no internal problems. It may or may not be a good stunt engine but it will run.

      Brett
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Offline Balsa Butcher

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Re: magnum pro 25 wont run properly
« Reply #4 on: October 03, 2013, 07:14:16 PM »
Start with the easy to change things...plug, diffferent batch fuel, loose back plate, plugged spray bar. You haven't told us how you are running it, what prop and what rpm in particular. If you are running too large a prop and/or trying to make it run in t 4/2/4 like a Fox 35 it may be telling you it does not like to be run that way. For this engine low pitch prop, high RPM would be the way to go. 8)
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ron young

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Re: magnum pro 25 wont run properly
« Reply #5 on: October 03, 2013, 07:33:54 PM »
Quote from: Brett Buck on October 03, 2013, 06:08:43 PM
   It's really hard to understand what you wrote here, but yes, the engine will run reliably if it is fed fuel and air, and has no internal problems. It may or may not be a good stunt engine but it will run.

      Brett
yes in addition to my mechanical difficulties I have trouble putting my thoughts down,but I thought I would try anyway Ron
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ron young

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Re: magnum pro 25 wont run properly
« Reply #6 on: October 03, 2013, 07:39:26 PM »
    Thanks guys I will run through the above ideas and try
Quote from: Chris Sarnowski on October 03, 2013, 03:32:57 PM
Hi Ron,

One thought is that you have an air leak some where if the engine is not responsive to the needle valve adjustment.

Check to make sure that your engine's back plate screws are tight, and also that there is a gasket on the backplate (probably clear mylar on that engine).

Test/inspect the fuel line for leaking (pull it off, pinch one end, try to blow through it). Might just want to replace it anyway. Also check that fuel filter (if using one) is not leaky.

What kind of needle valve are you using? An OS type needle valve can leak on threads. I usually put a piece of fuel line on the threaded shaft so it reduces leaking.

Pressure test your fuel tank (remove tank from model, cap off vents, try to push air into fuel feed line with syringe). Easy to see leak bubbles if you put it into bowl of water.

Those are some easy things to check. Good luck!

-Chris
I will give these a try let you know what I find thank you
Ron                                                                                                                                                                                                     
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ron young

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Re: magnum pro 25 wont run properly
« Reply #7 on: October 03, 2013, 07:49:01 PM »
I forgot to check the back plate.I am running apc 9/4 prop the problem is I cant get any rpm seems to be fat to me.I believe I forgot the needle is bent a bit out toward the knob I don't know if there is other nva assemblies that will interchange on this motor I did a little search and didn't see any info about the engine.
thanks for your help
wish I could communicate a bit better
Ron
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Offline Balsa Butcher

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Re: magnum pro 25 wont run properly
« Reply #8 on: October 03, 2013, 08:00:51 PM »
I may be mistaken here but I think the Magnum Pro is a ball bearing engine. If so it should be more powerful than an FP or LA-25. After trying all the other things that have been suggested try an APC 10-3 or 10-4 prop. More diameter may help steady the run. 8)
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ChrisSarnowski

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Re: magnum pro 25 wont run properly
« Reply #9 on: October 03, 2013, 08:41:43 PM »
Hi Ron,

This engine is likely an RC type that has been retrofitted with venturi and needle valve assembly. It is possible there is something not right with the needle valve assembly. Below is a picture of an OS 25 FP needle valve assembly, and it is possible you have one of these on your Magnum 25 pro.

If you unscrew your needle and look at it, it should be nice and straight. If not that is one problem and you would need a replacement needle.

You should also check that the needle can seat properly and close down the air flow. Put a piece of tubing on the spray bar then screw the needle into place a little bit. You should be able to blow air through the tube and out the spray bar. Start slowly screwing in the needle (gently). Eventually you should be able to slow down and stop the flow of air through the needle. Do not screw the needle in tight once the flow of air stops. That could also mess up the needle or valve seat. If you can't stop or nearly stop the air flow then you need to replace the needle valve assembly.

If you have one like the OS that I show, you need to take some measurements to get replacement. There are Enya needle valves that look similar but have different spray bar diameter.

-Chris
 
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Online M Spencer

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Re: magnum pro 25 wont run properly
« Reply #10 on: October 08, 2013, 06:07:09 AM »
Anyone know where you can get the real McCoy N V A for these things , theyre relieved at the middle / smaller Diameter .Otherwise similar to Super Tigre 21 series dimensions - they fit .

Std is peripheral hole venturie , dimensions similar to ' C 35 ' Super Tigre one , - they fit . Std one is small ( 3.5 mm odd ) hole .

Im after a few Magnum 25 / 40 NVAs & Venturies , for MAGNUM GP 25s . ( hence above info . Years bach I used the Magnum NVA in a McCoy 35 redhead - thus  resulting bigger area .

SO for the Magnum I used a Fox 25 intake , a round one with a 7.5 mm bore , and filed the bit that plugs in the case down a mm to plug in , and used a Taipan N V A .
used the old cow again the other day . Fell out & into prop & bent spraybar at needle , Fear Not , I bent it back ( eventually  '') so it adjusts freely , leaks air , and burrbles nicely again .

 n~ D>K H^^


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ron young

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Re: magnum pro 25 wont run properly
« Reply #11 on: October 08, 2013, 05:41:05 PM »
  Thanks fellas for the responses turns out i didnt have venturi hole properly aligned with spray bar hole once i finally got em right it runs pretty consistent for me.it will be ok for me to try to learn the pattern.
Ron
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ChrisSarnowski

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Re: magnum pro 25 wont run properly
« Reply #12 on: October 09, 2013, 05:53:24 AM »
Glad to hear you have solved your problem, Ron!! Good luck and happy flying!!!

-Chris
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