Glow Engines Discuss RC glow engines

Glow engine woes...

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Old 08-21-2012, 01:22 AM
  #26
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Default RE: Glow engine woes...

apart from the plug heat range and mixture issues, idle also may be unreliable when the carb is not clean, down around the needle tip.
15% nitro fuel should give reliable idle unless the engine is mounted inverted. In that case adding idle glow will allow lower idle rpm.
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Old 08-21-2012, 04:27 AM
  #27
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Default RE: Glow engine woes...

Quote:
I wouldn't think someone would pay monthly storage charges unless there was quite a bit of valuable items inside.
That is why the guys running low nitro will often use very hot glowplugs. Unless it was made for no nitro then you may have to use a cool plug.
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Old 08-21-2012, 04:30 AM
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The designer of these motors worked for OS and they had an ugly parting of ways so the story goes. He took his designs to Sanye as a parting shot.
No, Sanye simply bought a few OS engines and measured all of the parts and did some hardness testing, etc. and copied them. The story you mentioned was that the designer went to Thunder Tiger. That company then made original designs that were very similar to OS but not exact copies, thus many parts do not fit.
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Old 08-21-2012, 04:34 AM
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Ya, the machine finish is not OS quality, but that cosmetic stuff doesn't make any difference how they run if they're set up correctly.
Most are good, but some I have, had soft or brittle parts. The metal is not as good as an OS. The quality goes a little deeper than the finish. Unlike others such as Enya, Fox,. a few Rossi models, andmany gas models that have little finishwork, somewith an industriallook, but are actuallymade well.
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Old 08-21-2012, 05:49 AM
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Default RE: Glow engine woes...


Quote:
ORIGINAL: acerc

A friend has asked me a question that I can't answer. How about you guy's. The engine is a Magnum 120 4stroke. When started upon removal of the glow plug the rpm's increase. What would cause this?
I have an OS52FS that does the same thing
My question, mine also coming off WOT or landing also has a low idle then RPM slow climbs to a high idle an hard to land been casing it all summer
does yours pick any RPM as it idles.
rich
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Old 08-21-2012, 05:53 AM
  #31
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Delete RCU error
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Old 08-21-2012, 07:27 AM
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Default RE: Glow engine woes...

There was a lot of mystery and secrecy behind the emergence of ASP engines produced part time from a government operated plant. The first ASP 40 was not a clone and had a lot of power. The case resembled OS, but the stroke, bore, ports, etc were different and timed much more aggressively. ASP never used nickel liners. The first ASP 40 was known to be a hot engine. However, the carb was very close to the OS. Evolution engines are newest addition to Sanye, and these seem to be designed with different goals than Magnum and ASP.
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Old 08-21-2012, 07:35 AM
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Default RE: Glow engine woes...

I and others in our club have had good luck with Magnum TS and FS engines however one member had a new 91FS that would not run right in the air. It would always sag out . Tried everything from carb adjustments,plugs, fuel, etc.. until one day it died and the plane had a hard landing. The owner sent it back to the factory and they said they rebuilt it and was running fine. He got it back,broke it in and re-mounted it on the plane. First flight was OK, second flight it sagged out, died and the plane crashed . Now the engine is a paperweight. Every company has a lemon every now and then.
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Old 08-21-2012, 08:55 AM
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Default RE: Glow engine woes...

While you're checking the o-ring at the carb, make sure the gasket at the manifold/block is good too and these bolts are tight. I have found broken gaskets on new engines. One other thing, I've had several Magnum/ASP 4 strokes break valve springs which can cause the engine to not run at all or be well down on power. Just pull the valve cover to take a peek. Sometimes it's hard to see but if you set the enging on compression at TDC then deflect the rocker, you can tell if one is considerably less tension than the other.

Finally if you use a hardware store o-ring be careful when reassembling it to make certain it remains in place and isn't pinched when inserting the manifold. If it is not the exact size required then they tend to push out of the comparitively shallow o-ring groove in the carb. I generally use some "hobby" (rubber safe) grease to make them slip together easier.
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Old 08-21-2012, 10:08 AM
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Default RE: Glow engine woes...


Quote:
ORIGINAL: richrd


Quote:
ORIGINAL: acerc

A friend has asked me a question that I can't answer. How about you guy's. The engine is a Magnum 120 4stroke. When started upon removal of the glow plug the rpm's increase. What would cause this?
I have an OS52FS that does the same thing
My question, mine also coming off WOT or landing also has a low idle then RPM slow climbs to a high idle an hard to land been casing it all summer
does yours pick any RPM as it idles.
rich
My best guess is air is getting into the engines case or from fuel tankair getting in leans the mixture
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Old 08-21-2012, 11:37 AM
  #36
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Default RE: Glow engine woes...

Wow!  What a thread this turned out to be.  All I wanted to know was how to get the thing to idle (which it has done in the past with the previouse owner, exact same setup).  Don't get me wrong, a lot of good info here, some of it just went beyond. 

I'll try to digest all of this but can't promise that I'll get back to all of you, esepecially with personal time constaints.  Darn life keeps getting in the way! 

Thanks again!
David
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Old 08-21-2012, 12:52 PM
  #37
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Default RE: Glow engine woes...

Quote:
15% nitro fuel should give reliable idle unless the engine is mounted inverted.  
?  None of my 4-strokes run differently when mounted inverted. The engine doesn't know! I believe the crankcase pressures preclude any effect from gravity. The bigger issue, I've found, is fuel tank height relative to carb, which will lead to grief no matter how the engine's mounted if done too high or low..
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Old 08-21-2012, 01:54 PM
  #38
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Default RE: Glow engine woes...

My OS 15cc knew very well when it was inverted. Upright idle would be fine, turning the plane back on it's feet made the engine die without glow support. Tank middle was at fuel jet height. Killing the glow made the engine stop. Nice setup with only 2% nitro BTW.
More nitro may blanket the differences, so you won't notice.

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Old 08-21-2012, 02:09 PM
  #39
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Default RE: Glow engine woes...

Nitro does make a difference, I agree. Some of my 4-strokes turn into raging beasts on 30% heli fuel, but what's the point?

I picked up an OS 70 Surpass that was nearly new for $50 from a club member who couldn't get it to run consistently in the inverted mounting. It's running fine inverted in a Cub. I do run 15% in all my engines, which may be a bigger factor then I thought.
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Old 08-21-2012, 04:42 PM
  #40
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Default RE: Glow engine woes...

I have a 91 Magnun 4 stroke. It was already installed in a plane I bought used. The thing starts w one stick flip ( if adequately primed), iddles beautifully and has enough power.
All my other 7 engines are OS and Saitos[:'(]
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Old 08-21-2012, 08:07 PM
  #41
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Default RE: Glow engine woes...

Cub Flyer Fresno,

With all the responses you have received and attemps you have tried this problem should have been fixed. Since you indicated that this engine was previously owned, it brings in some other thoughts. There are some simple parts that over time do wear and cause poor performance. Vacuum leaks are something that can be a real pain and hard to detect. I would suggest looking at the O-rings at the carburetor base and the one along the inside of the needle valve. If a air/vacuum leak exists then once you attempt to idle, the fuel mixture is affected towards the lean side. These are simple things to fix and could be the culprits to your poor performance. Of course, that is not the only area where you can address. whenever I rebuild a four stroke I examine and clean the cylinder head, valves, and adjust the valve lash. Remember you said this was a used engine, these things do wear and can and should be adjusted. It doesn't cost much to address both these sugestions and it doesn't mean your engine is worn out or in bag condition. Sometimes it's the simple things that are the most difficult to believe are the cause of the problem.

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Old 08-22-2012, 05:31 AM
  #42
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Default RE: Glow engine woes...

Well Sledge_78, I think that's the best info I've read yet! Since this plane has been hanging around for a while, those seals could very well be compromised. The previous owner did take care of it, using after run oil and all, but if that oil didn't get to the O-rings...

The valves have been adjusted but the timing wasn't checked, but by the way it runs from about 1/3 throttle and up, I would doubt it's timing.

When I get a chance I'll tear into the seals (O-rings)and replace them. What could that hurt? Of course... I could be totally wrong...

This is great stuff! Okay, back to everyone else, take it away!
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Old 08-22-2012, 11:12 AM
  #43
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Default RE: Glow engine woes...

So you have increasing high idle rpm with glow removed AND bad running above 1/3rd throttle??? What about that said in post #4 where the engine runs well but the only problem is not obtaining good low to high idle without glow?
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Old 08-22-2012, 11:25 AM
  #44
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Default RE: Glow engine woes...

Like the Eveready bunny.....
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Old 08-22-2012, 11:39 AM
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Default RE: Glow engine woes...

No, it runs great from about 1/3 throttle (+/-) on up.  At idle is where it will only run a second or so and then just quit.  It's like it is running out of fuel.  That's why I am starting to lean more and more to O-rings.

Does that make sense, or is it just me?
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Old 08-22-2012, 06:17 PM
  #46
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Default RE: Glow engine woes...

Hey guys,

I got back to this engine again. I took the cowl off so I could see things a bit better. I reset the LS needle to factory default and tried to run it. It was hard to keep running at even 1/2 throttle. After about three tries I went to adjust the LS needle and noticed it was wet. Upon screwing it back out I noticed it was bubbling around the screw. As I said before, this plane had been hanging around for some time, not sure how long, but my guess is that the o-rings need changing. ([X(] SHOCKER!)   In fact I think I'll change all of them since I have the engine out.

Comments, suggestions, etc., etc.?

Thanks for all the help guys!
David

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Old 08-22-2012, 06:51 PM
  #47
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Default RE: Glow engine woes...

Gee, look at what else I found! Didn't somebody mention something about that? Anyway, off to get some new o-rings!
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Old 08-22-2012, 08:28 PM
  #48
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Default RE: Glow engine woes...


Quote:
ORIGINAL: jeffie8696

Auto parts store?
As an aside, I am not a huge fan of Magnum engines but I have a 52 FS on my Escapade and have flown it for several hours now with great success.
It took a long break in but it runs like a champ now. It lacks the refinement of my Saitos but it also lacks the price tag.
I purchsed a Saito 62 to replace it but to tell the truth I am so happy with the Magnum 52 that I am dragging my feet swapping it out (that and I am a lazy SOB lately).
I landed some 30% nitro fuel for cheap, and the 52 LOVES it !!


Remember, the flame that burns twice as bright - lasts half as long.


Ed Cregger
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Old 08-22-2012, 08:38 PM
  #49
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Its worth it.
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Old 08-22-2012, 09:55 PM
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Default RE: Glow engine woes...

The whole engine gasket kit that contains the o-rings for the intake manifold is real cheap, the hobby shop might have it. The o-ring in a separate bag with a V on it (for Viton) goes in the head. Viton are a high temp type o-ring and are more durable.

A separate gasket set is sold for the carb I think.

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