Difficulty starting small engine

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  #1  
Old 02-07-16, 08:52 PM
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Difficulty starting small engine

Hi everyone so yesterday i bought a powerhorse 414cc engine for a go kart project I have. The butterfly valve was broken in the carb i fixed that. But I am having a hard time pulling the cord. The engine isn't seized but I am unable to start it. The pull cord is very difficult to pull it spins, but after about 15 pulls I am exhausted and unable to start it. I replaced the gas and changed the oil I plan on changing the spark plug tomorrow. Any suggestions would be appreciated
 

Last edited by Spencer2362; 02-07-16 at 09:32 PM.
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  #2  
Old 02-08-16, 04:44 AM
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Why did you buy an engine that was not running if you don't have the experience to get it running. If you verify the flywheel isn't offset, have spark at the plug and gas at the intake manifold, the engine should run. Good luck.
 
  #3  
Old 02-08-16, 05:30 AM
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If it's a used engine first thing I'd do is pull the carb. and at least clean of not rebuild.
Clean does not mean just blow some air in it, it needs to be sprayed with carb. cleaner in all the ports.
 
  #4  
Old 02-08-16, 05:59 AM
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If the butterfly in the carburetor was broken I suspect there may be other things wrong. Before touching the carb. I would remove the spark plug and pull the starter cord. Does is pull easy? Do you see or feel the piston moving up & down? If not you may not want to go any further and consider finding another engine.
 
  #5  
Old 02-08-16, 05:59 AM
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I would guess the compression release that is integrated with the recoil starter mechanism is not engaging as it should.
 
  #6  
Old 02-08-16, 08:40 AM
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I can feel the piston moving up and down the drive shaft turns when I pull the cord so thats good. The spark is good and I just tried pulling it with the spark plug out and it pulls nice and easy like its soppoused too.
 
  #7  
Old 02-08-16, 09:00 AM
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>> I just tried pulling it with the spark plug out and it pulls nice and easy...

That is because there is no compression with the spark plug removed...and all of that means you need to get the compression release working when you pull the rope.
 
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Old 02-08-16, 09:02 AM
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First I'd make sure the engine is properly filled with oil. Since it was hard to pull I'll assume compression is good and you said you have spark so that only leaves fuel. As a test you can remove the spark plug and put a teaspoon of gas into the cylinder, install the spark plug and give the starter cord some pulls to see if it sputters or runs for a second. If it runs just a bit it means the engine is probably OK and your problem is in the carburetor.
 
  #9  
Old 02-08-16, 10:15 AM
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What exactly do you mean by compression release? Also I tried starting it with a little wd40 because I didnt have any gas around my house and it didnt fire up.
 
  #10  
Old 02-08-16, 10:21 AM
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According to the Northern Tool listing for the latest version of that engine, it has what is know as a "compression release" mechanism that is activated by the rope recoil starter as you pull. I do not know the specifics for that engine, but there is a lever and/or mechanism of some kind that blocks a valve partly open as you pull in order to make it possible to pull-start that large of an engine. Look for a lever or linkage of some kind that is likely activated by a cam lobe near the recoil as you pull...and there you will discover how to "release" some of the compression as you pull.
 
  #11  
Old 02-08-16, 10:29 AM
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Name:  20160208_122727.jpg
Views: 187
Size:  39.5 KB Would it look like this?
 
  #12  
Old 02-08-16, 10:57 AM
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try looking here at 0:44 ...

https://www.youtube.com/watch?v=FklhA0uKdkc
 
  #13  
Old 02-08-16, 11:19 AM
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Ya that silver lever i tried that i have to turned to the setting according to the start instructions.
 

Last edited by Spencer2362; 02-08-16 at 11:47 AM.
  #14  
Old 02-08-16, 11:52 AM
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Generally compression release is inside the engine. One method has no moving parts and the cam is shaped to hold a valve slightly open for a brief period. When the engine is turning slow it's enough to release some compression and make pulling the cord easier. When the engine is running and turning faster not much air can escape in the short period it's open. More popular is a centrifugal weight on the camshaft that prevents a valve from fully closing at low rpm's and when the engine is up to running rpm's it pulls out of the way allowing the valves to fully seat.
 
  #15  
Old 02-11-16, 04:11 PM
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Alright so improvement today I found out that there was a loose bolt on one of the valve springs so that is why it was difficult to pull because only 1 valve was working. So now it pulls easy and i tried using starter fluid but flame just shoots out of the carb. I cleaned every little thing in the carb, the bowl fills and the float works i cleaned the jet. But it still wont run any ideas?
 
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Old 02-12-16, 05:31 AM
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You're doing more than just cleaning if you've got the valve cover off and adjusting things and being very specific is important. What specifically did you do to the valve and what was the "loose bolt"? Did you adjust the valves and set the proper gap?

Starting fluid is not the best. If the engine is in a runable condition it will run. If you are testing to see if the carb is not working I prefer to put a teaspoon of gas down the throat of the carb or right into the cylinder through the spark plug hole.
 
  #17  
Old 02-12-16, 08:24 AM
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I was just looking under the valve cover but the nut on top of one of the springs was very loose so when i would pull the cord it wouldn't even move but the other valve did. So i tightened it and now they both move when i pull it and it pulls easily now. Also i will try that with the gas
 
  #18  
Old 02-12-16, 09:36 AM
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Valve adjustment is sorta critical. Most engines don't have the rocker arm touching hard on the lifter or valve. There is usually some small gap so when the engine is turned to the right spot the rocker can seem loose and be free to move. If the gap is not set properly is can affect the valve timing and when the engine gets hot and things expand they need room to grow.
 
  #19  
Old 02-12-16, 04:12 PM
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I think one of them might have worked its way too loose so should i leave them a little loose? because now every time i pull the cord it fires but wont stay running.
 
  #20  
Old 02-12-16, 04:52 PM
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Do you have a "Feeler Gauge" so that you'll know what a little loose is ?

A little loose might be 0.006" while 0.004" might be too tight !

And the Exhaust Valve(s) might require a larger gap than the Intake Valve(s).

Just guessing won't get you very far; you'll need to get fairly precise.
 
  #21  
Old 02-13-16, 05:03 AM
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Search online for how to adjust your valves. You need to have the engine rotated to a specific position usually top dead center (TDC) or slightly off from TDC (to get off the compression release) when setting the valve gap.
 
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