un stopable engine!!!!!!!  
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un stopable engine!!!!!!! - 9/14/2008 2:53:29 PM   
hoochie187


 

Posts: 40
Joined: 8/16/2008
From: wirralnon, UNITED KINGDOM
Status: offline 		Can any one help me, I have an engine im trying to tune, but it will not cut out if you plug the exhaust, you can totaly plug the end and nothing happens at all,nothing, it just WONT stop, the only way to stop it is to ripp off the fuel line, and it still takes 5 seconds to stop. After you rip off the fuel line it revs up super high, even without the carb being open, its like the law of phisics dont aply to this one engine, mad. If you can help it would be much appresiated, Thank you.
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RE: un stopable engine!!!!!!! - 9/14/2008 3:01:11 PM   
guver


 

Posts: 9440
Joined: 3/7/2003
From: LaGrange, OH, USA
Status: offline 		Repair exhaust leak in system so that plugging outlet stops. Or perhaps you can plug carb intake or stop flywheel. That's all I know about nitros.

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RE: un stopable engine!!!!!!! - 9/14/2008 3:12:22 PM   
rageworks


 

Posts: 122
Joined: 12/13/2005
From: Alexandria, VA, USA
Status: offline 		Your exhaust isn't sealed properly. Check where the header fits onto the
engine and the coupler seal between the header and pipe. You will not
be able to tune the engine properly until you fix the exhaust leaks. You
may even have a crack in the header or the pipe. Good luck.

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RE: un stopable engine!!!!!!! - 9/14/2008 3:23:40 PM   
DaveG55



Posts: 6634
Joined: 1/12/2005
From: Stockbridge, GA, USA
Status: offline 		What they said about the exhaust not being sealed is correct. If the exhaust is sealed the engine will stop when the pipe is blocked. Also, simply pulling the fuel line does not immeadeatly stop a nitro engine. There is still fuel in the carb and in the crankcase. Basically pulling the fuel line is a form of the "pinch test" for checking the tune of the lsn. Since you're 5 seconds to stop your lsn is probably a bit rich (getting a high reving is susposed to happen) but don't start tuning the lsn until the hsn is properly tuned.

In short, your engine is indeed obeying the law of physics - it's just that you don't understand the physics of how and why a nitro engine works.

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RE: un stopable engine!!!!!!! - 9/14/2008 4:08:03 PM   
Argess



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From: Pleasantville, NS, CANADA
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Dave said: "In short, your engine is indeed obeying the law of physics - it's just that you don't understand the physics of how and why a nitro engine works."


Gee Dave...was that last comment really necessary?

< Message edited by Argess -- 9/14/2008 4:11:19 PM >

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RE: un stopable engine!!!!!!! - 9/14/2008 4:31:37 PM   
DaveG55



Posts: 6634
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From: Stockbridge, GA, USA
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quote:

ORIGINAL: Argess


Dave said: "In short, your engine is indeed obeying the law of physics - it's just that you don't understand the physics of how and why a nitro engine works."


Gee Dave...was that last comment really necessary?



Hmmmmmm, yes, I think it was. I colud possibly have said it a bit less bluntly but too many people say things like "it's not obeying the laws of physics" when a few minutes of studying what the physics are would show the problem. And when you understand how and why something works it's usually a simple next step to rule out what is normal behavior find out why something is not doing something it should.

So, if the OP took offense to the way I said that then I appologize.
But the fact still stands that if you'll learn how and why your engine operates you'll be able to think through many problems and find this hobby a lot more rewarding.

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RE: un stopable engine!!!!!!! - 9/14/2008 5:36:58 PM   
hoochie187


 

Posts: 40
Joined: 8/16/2008
From: wirralnon, UNITED KINGDOM
Status: offline 		Im not affended, I have, tried to learn about these little head workers, but i understand about the exhaust not being fitted right, the gasket is a bit ripped but i thought it would still work, (maby not) can any one explain why an engine revs SO high when you pinch the exhaust line, and how it revs high with the carb totaly shut, and if any one could explain what the exhaust tube that connects the fuel tank does, (i think it forces fuel into the carb) i need to know this stuff to broaden my knowlage of these engines, as you can probably tell im new, but i want to buy and sell on ebay to make a bit of money and learn about these cars as a hobby, they are, very impresive machines, any one who can explain this would be a great help, sites only seem to tell you about tuning an engine that is runnig well, I need to know how to get engines that dont work back to optimum power thank you.

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RE: un stopable engine!!!!!!! - 9/14/2008 5:53:21 PM   
Nik.



Posts: 1080
Joined: 3/28/2007
From: ., CA, USA
Status: offline 		it revs becuase without fuel it runs very lean.

the line from the pipe to the tank pressurizes the tank so fuel is drawn to the carb.

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RE: un stopable engine!!!!!!! - 9/14/2008 7:15:56 PM   
Technex



Posts: 274
Joined: 7/5/2008
From: Berkshire, UNITED KINGDOM
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quote:

ORIGINAL: DaveG55

What they said about the exhaust not being sealed is correct. If the exhaust is sealed the engine will stop when the pipe is blocked. Also, simply pulling the fuel line does not immeadeatly stop a nitro engine. There is still fuel in the carb and in the crankcase. Basically pulling the fuel line is a form of the "pinch test" for checking the tune of the lsn. Since you're 5 seconds to stop your lsn is probably a bit rich (getting a high reving is susposed to happen) but don't start tuning the lsn until the hsn is properly tuned.

In short, your engine is indeed obeying the law of physics - it's just that you don't understand the physics of how and why a nitro engine works.



This quote is true, and you can pinch the line not pull it. Do this every time you turn off the engine, I never plug the exhaust and I don't think it's a good idea too flood the engine while it's in use.

Lean the LSN a few 1/8ths one at a time. You want around 3-4 seconds if I remember correctly.

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RE: un stopable engine!!!!!!! - 9/14/2008 7:57:13 PM   
hoochie187


 

Posts: 40
Joined: 8/16/2008
From: wirralnon, UNITED KINGDOM
Status: offline 		Can an air leak in the manifold act like an open throttle in a way.

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RE: un stopable engine!!!!!!! - 9/14/2008 8:03:02 PM   
guver


 

Posts: 9440
Joined: 3/7/2003
From: LaGrange, OH, USA
Status: offline 		Yes, in the intake.

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RE: un stopable engine!!!!!!! - 9/14/2008 8:21:51 PM   
hoochie187


 

Posts: 40
Joined: 8/16/2008
From: wirralnon, UNITED KINGDOM
Status: offline 		What do you mean on the intake, like its sucking air in and making the fuel explode quicker.Would it be impossible for the engine to not rev high with a air leak at the manifold, also any one know were you can buy cheap gasketes £2-3 for a bit of rubber WHAT!!

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RE: un stopable engine!!!!!!! - 9/14/2008 8:50:41 PM   
guver


 

Posts: 9440
Joined: 3/7/2003
From: LaGrange, OH, USA
Status: offline 		Any intruduction of air into the motor will make it rev up and produce power if the fuel is somewhat close to correct ratio. That's on the inlet side of engine (intake) . The carb is just a "controlled leak" per say. If it was closed completey the engine would stop , the same as if the exhaust were closed off completey.

< Message edited by guver -- 9/14/2008 10:50:54 PM >

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RE: un stopable engine!!!!!!! - 9/14/2008 9:46:43 PM   
Argess



Posts: 521
Joined: 1/12/2006
From: Pleasantville, NS, CANADA
Status: offline 		Dave said: But the fact still stands that if you'll learn how and why your engine operates you'll be able to think through many problems and find this hobby a lot more rewarding.


I absolutely agree, and not just for the engine. With regards to my first comment......I need to learn to mind my own business a bit more.

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RE: un stopable engine!!!!!!! - 9/14/2008 10:38:07 PM   
hoochie187


 

Posts: 40
Joined: 8/16/2008
From: wirralnon, UNITED KINGDOM
Status: offline 		Your knowlage is greater than mine,. so you may say whatever you want but hopfully soon i will answer your questions.

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RE: un stopable engine!!!!!!! - 9/16/2008 1:39:17 PM   
larryf333


 

Posts: 126
Joined: 7/16/2008
From: Acworth, GA, USA
Status: offline 		I have some info for you. I don't know if you will find this helpful or not, but here it is,

I will state my opinion on your particular problem first. First for the gasket leak, you can buy regular automotive gasket material and make your own gaskets out of them. This will save you quite a bit of money, just cut the shape of the RC gasket you need out of it. You can normally get quite a few RC gaskets from a single auto gasket. I'll give you a little info as to how the flow of fuel works. It obviously starts out in the gas tank, then as you spin the motor on start up the fuel tank becomes pressurized. This is what the line running from the exhaust pipe to the top of the gas tank is for. As the tank becomes pressurized it pushes fuel to the carb, which in turn sucks in air and mixes it with the fuel. This mixture is then drawn into the motor through one or more ports as the engine's piston cycles down. As the piston cycles back up it compresses the mixture in between the top of the motor where the glow plug sits and the top of the piston, when the pressure reaches a certain point, combustion occurs and propels the piston down. After combustion of the nitro in the fuel, what you have left is oil, which lubricates the engine. This is the liquid you see shooting out the exhaust pipe with the smoke and makes a mess on everything. If you have any leaks in the system it will cause the motor to run erratically and make it impossible to tune properly. Fuel tubing is cheap, you can get several feet for a couple of bucks and replacing the tubing is the first place I would start. Then check the engine and exhaust gaskets and