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MOKI RADIAL Care and Maintenence

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Old 05-31-2014, 01:04 PM
  #2926
reyn3545
 
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Can the ignition module get hot and shut off?

I've had my 250 running a little on the ground, just trying to break it in a little before flying. I know I should break it in flying, and I will, just not enough free time right now. Yesterday, and again today, after maybe 5 minutes of running at slow speeds, the motor shut off. Just like you turned off the ignitiion. You can try to re-start, and it might run for 5 seconds, but it will die again.

Yesterday I assumed that maybe I had a fuel tubing issue or something like that. I checked all that out today, charged the batteries and went back outside... same situation. After about 5 minutes, it just cut off. Gotta be the ignition.

I took the cowl off and ran the motor again... cranked right up, but only ran for about a minute before it cut off.

When it stops, it's just like you cut the ignition. Just a dead stop. I need to check all the wiring to be sure I don't have an intermittent connection, but I think everything is solid.
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Old 05-31-2014, 02:00 PM
  #2927
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Unfortunately, I think I found my problem. The grey ignition wire running from the ignition module to the coils inside the motor housing was touching my exhaust ring. The outer insulation didn't melt through and expose any bare wires, but it did melt at least some of the outer layer.

Not sure now if I can replace just that cable, or if I need to replace the coils. I've got a note into Goetz, we'll see what he says.
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Old 06-01-2014, 09:15 AM
  #2928
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I have two comp arf planes with moki 250's. Carf suggests a 50 oz tank. The p-47 I bought came with an 80oz tank. I feel like this is overkill and will be packing two pounds of extra weight on every flight. What is the flight average time on the 50oz tank??
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Old 06-01-2014, 11:29 AM
  #2929
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I think a 50 ounce will give you as much flying time as you want.
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Old 06-01-2014, 11:49 AM
  #2930
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reyn, yes the module can get too hot. It should not be in the engine area, rather behind the firewall. -Tom
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Old 06-01-2014, 04:43 PM
  #2931
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I doubt that the coils got damaged but I guess it's possible. Do a continuity check on each wire in the cable.. If the grey plastic outer got a hole melted in it it's possible that the wire insulation inside melted at that spot and shorted while running but not when it's stationary.. There might be enough movement of the cable while the engine is running to make wires touch. While doing the continuity check wiggle the cable and see if that turns up the problem. Good luck. Mitch
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Old 06-02-2014, 08:44 AM
  #2932
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I have an early version Moki 150. I have heard that there is an RPM governor built in to the ignition. Is that true? If so:
1. What RPM does it limit the engine to? I have heard it is 5500, but I want to know for sure.
2. What is the behavior when the engine exceeds the maximum RPM? Does the ignition cut out until the RPM is below the maximum?, or what does it do?
Thank you.
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Old 06-02-2014, 03:40 PM
  #2933
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Quote:
Originally Posted by DrScoles View Post
I have two comp arf planes with moki 250's. Carf suggests a 50 oz tank. The p-47 I bought came with an 80oz tank. I feel like this is overkill and will be packing two pounds of extra weight on every flight. What is the flight average time on the 50oz tank??
I installed a 40oz tank into my P-47 and after 8 minute flights there is still around a half tank left over. So i'm sure it is good for around 12 minutes. If your looking for longer flight times then 50oz will work just fine.
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Old 06-03-2014, 02:52 AM
  #2934
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Quote:
Originally Posted by bcrc View Post
I have an early version Moki 150. I have heard that there is an RPM governor built in to the ignition. Is that true? If so:
1. What RPM does it limit the engine to? I have heard it is 5500, but I want to know for sure.
2. What is the behavior when the engine exceeds the maximum RPM? Does the ignition cut out until the RPM is below the maximum?, or what does it do?
Thank you.
bcrc,
I have found out this question in an interesting way{not recommended}.
While starting my 150 on the test stand I had inadvertently reversed my throttle servo. After 2 flicks it started in full throttle!!!!
Before I could gather my thoughts and react in any way it reached high revs. and then immediately started to oscillate from high to low revs. at a frequency of about one or two cycles per second!
I turned the engine off quick -smart , calming my nerves and started to count my lucky stars.




I am not sure whether this was the so called " over rev cutout" or not, I am at ease now, knowing the engine will not over rev into a dangerous range and destroy itself.
Regards, Karl-Heinz.
P/S, judging by the sound, it did not appear to be in the extreme high range!
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Old 06-03-2014, 04:13 AM
  #2935
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Kipuetz, You must have a way too small prop on your engine. I use a SEP 28x14. On the bench I would set it up for 4500 rpm or so because it will unload in the air. The rev limiter should not be allowed to be reached. Yes that was a dangerous situation and also hard on the engine. Glad you are OK. -Tom
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Old 06-04-2014, 06:56 AM
  #2936
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The number three cylinder issue! A friend of mine was at the Joe Nalley event this year and had the opportunity to talk with one of the design engineers for the Moki radial engines. The gentlemen suggested to adjust the engine by the Number three cylinder, bringing the temp up to 165 F and forget about the rest of them. Can any one confirm that?
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Old 06-04-2014, 08:10 AM
  #2937
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Not good enough for me. With Detlef Kunkel's turbulator I was able to bring my 150's over 100 degree Fahrenheit deviation between the hottest and coldest cylinder to within 20 degrees resulting in a vastly better running engine. This device greatly improved this situation on my 215 and a 215 I used to own too. Its temp deviation was not as bad but I got the cylinders within 5F of each other! What if you adjusted the coldest cylinder to 165 F and the hottest one was 265F? One very unhappy engine! Gotz at vogelsangaeroscale.com has them. Unfortunately the turbulator cannot be used on post 2009 150s..:-( -Tom
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Old 06-04-2014, 01:49 PM
  #2938
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Gotz told me to just cut a slice out of an aluminum beer can and use it as a feeler gauge. that what his feeler gauges look like, and they work perfect...
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Old 06-04-2014, 02:06 PM
  #2939
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Quote:
Originally Posted by bcrc View Post
I have an early version Moki 150. I have heard that there is an RPM governor built in to the ignition. Is that true? If so:
1. What RPM does it limit the engine to? I have heard it is 5500, but I want to know for sure.
2. What is the behavior when the engine exceeds the maximum RPM? Does the ignition cut out until the RPM is below the maximum?, or what does it do?
Thank you.
...but, please: can anyone just tell me what the rev limit is, and what is the behavior of the ignition when the rev limit is reached.
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Old 06-04-2014, 02:20 PM
  #2940
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Quote:
Originally Posted by Remaking View Post
Gotz told me to just cut a slice out of an aluminum beer can and use it as a feeler gauge. that what his feeler gauges look like, and they work perfect...

Is that a USA beer can or a German beer can LOL LOL just could not resist.......
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Old 06-04-2014, 03:01 PM
  #2941
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I see there is now a 300cc 5 cyl. and a 350cc 7 cyl. added to the Moki family of radials. I have yet to see/hear a 250cc 7 cyl., has anyone? I wonder how the sound compares to the 5 cyl.? I'm thinking the 5 would sound better than the 7, though a 7 would look better stuck on the front of a Stearman, but not sure??? Anyone been able to compare the "musical" notes of our round wonder?
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Old 06-04-2014, 03:50 PM
  #2942
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There is someone running a 250 7cylinder on youtube. -Tom
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Old 06-05-2014, 06:30 PM
  #2943
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I've read through this thread and taken notes. Still haven't found a clear cut tutorial on how to adjust the valves. Is there one? A video would be outstanding! Gotz offered to walk me through it on the phone, hate to take up his time. I have the tools, just not sure how to confirm TDC. Do I remove the plugs?

Thanks
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Old 06-05-2014, 08:39 PM
  #2944
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Yes a video would be helpful!



Joe
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Old 06-06-2014, 08:24 AM
  #2945
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I don't remove the plugs. When both rockers are free on a cylinder, that cylinder is in compression. I check those two and then move on to the next. Not too hard to figure out. It has worked just fine. On a new engine, I find that after about 10 flights, they are all worn in. Very few adjustments are needed after that.

On dead cylinders, excess exhaust smoke is always visible. A tell tail sign you have a cylinder not firing. The exhaust tube will be cold on the offending cylinder. I watched Gotz check this way. It is simple and quick. Just lick your fingers before checking.
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Old 06-06-2014, 11:37 AM
  #2946
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Post #209 and #213 within this thread give a good adjustment procedure that I follow. It is pretty simple and you don't even need a feeler gauge.
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Old 06-07-2014, 05:30 AM
  #2947
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I spent half an hour on the phone with Gotz yesterday. Its pretty easy to do adjust the valves. I also got a new video camera as an early fathers day present. Once I do it a few more times, I'll make a video.
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Old 06-07-2014, 02:26 PM
  #2948
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Anyone got a spare ignition module for a 250? I think mine is bad.
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Old 06-07-2014, 02:34 PM
  #2949
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Quote:
Originally Posted by Maxam View Post
Gonzalo, You have everything you need to have a great running engine. Use Redline or Amsoil interceptor 44 to 1 and later 50-1 and you will be set.
Maxam:

Thanks for your answer.

Still not convinced about the old ignition and seriously thinking about investing in the new type..... anybody has operated both types in order to compare how the engine performs with each one ?
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Old 06-08-2014, 09:08 AM
  #2950
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I'm told by users that the new ignition doesn't add any performance but it allows the use of unregulated LIFE and Lipo voltages. I also expect that the new one has much better reliability. MItch
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