Low compression on Powerhorse engine

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  #1  
Old 03-26-16, 07:53 PM
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Low compression on Powerhorse engine

Hi everyone I have a powerhorse 414cc engine that i found in my garage. I am trying to get it running it has spark it has gas. I broke the pulling mechanism so I am using a drill and socket. when you turn the engine by hand it has like a hard point it is slightly easy to turn but there is a spot to where it is very difficult to turn and when it is hard to turn you can like hear air releasing im not sure if it is from the exhaust valve or where. Anything anyone could provide would help I would like to get this running. Thanks
 
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  #2  
Old 03-27-16, 04:17 AM
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There will always be some leakage and it's possible your engine has a compression release. Before worrying about compression I'd attack the other two parts of the triangle first; fuel and ignition. Are you getting spark? Did you remove, disassemble and clean the carburetor?
 
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Old 03-27-16, 08:27 AM
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Yes I checked it has spark and i cleaned the carb and it is getting gas. I dont know if it might be I had to adjust the valve springs because one of the nuts came off so i put it back to manufacture specs but it didn't do this when the valve needed adjusting
 
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Old 03-27-16, 11:31 AM
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Some further info on the engine would be helpful.
Also, using a drill and socket to spin the engine!?!?!?!?! This can be extremely dangerous should the engine actually even attempt to start let alone start!!!
 
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Old 03-27-16, 11:57 AM
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Thats about all I know about it is that it is a Powerhorse 414cc it use to be on a generator it has a clean carb and good spark. Yes I am starting it with a drill and socket i have found it very helpful in starting it is not dangerous at all and is very useful.
 
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Old 03-27-16, 12:58 PM
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Are you using the drill on the flywheel nut?

If you are serious about getting it running, I would advise fixing The starter rope, it can be a bit tedious but not expensive and can be educational, and above all safe!
 
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Old 03-27-16, 01:30 PM
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How did you determine the nut was installed back to factory spec?
 
  #8  
Old 03-27-16, 05:35 PM
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Yes I am putting it on the flywheel nut. I looked up the proper gaping for my engine and i contacted the manufacture and he told me that it was a .004 gap on the intake valve and a .006 gap on the exhaust and i used a filler gauge to measure it.
 
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Old 03-28-16, 12:38 AM
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Did you make sure the engine was on TDC when you did this?
 
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Old 03-28-16, 10:19 AM
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On racing kart engines we use external electric starters on the flywheel nut with a socket. The starters have a one way clutch so when the engine starts the clutch releases so the starter doesn't get dragged by the engine. Using a drill for starting can be "painful". If the motor starts and is turning faster than the drill it will spin/rip the drill out of your hand.
 
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Old 03-28-16, 04:08 PM
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Yes I am starting it at TDC and once it does a full revolution back agian to TDC is at the hardpoint. Also, Dane I have the socket just sitting on a bit on the drill so if it starts i can always pull it right off.
 
  #12  
Old 03-28-16, 06:15 PM
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So I was trying to fire it up and it fired once and the nut that holds the valve cover on blew off and strip all the threads out.
 
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Old 03-28-16, 09:18 PM
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.
 
  #14  
Old 03-29-16, 12:17 AM
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I'll take a cup too Scott.

The valve cover blew off, as in explosion, or as in something hit it from the inside and knocked it off? Does the oil smell like gas?
 
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Old 03-29-16, 04:36 AM
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I am confused when you say that you are starting it at TDC. Did you mean that you checked the valve gap at TDC or are you actually rotating the engine to TDC before attempting to start it? I am concerned that you say you have a "hardpoint" at TDC.
 
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Old 03-29-16, 07:28 AM
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[HR][/HR] Ya im not sure the only thing i can think of is that the breather isnt working and it built up to much pressure in the valve cover? But it fired and pulled the bolt clean out
 
  #17  
Old 03-29-16, 04:10 PM
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Yes I rotated it to top dead center before i adjusted the valves. I have to rotate it just past top dead center when i try to start it because at TDC it is very difficult to turn.
 
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Old 03-29-16, 09:24 PM
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If it fired just one time and that's it (as in one revolution or kick from ignition) then it wouldn't have run long enough to build pressure enough to blow anything and if it did, it probably would have blown the rubber crankshaft seals, not the valve cover. What about the oil question I asked? Did a push-rod come out when the valve cover came off? Are either of the valves looser then specs at any point in engine rotation? Are any of them tight the whole time through engine rotation? Are you rotating the engine clockwise from the top when you turn it to set the valves? You could have a flywheel key problem, not sure but these questions are part of the process to finding out.
 
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Old 03-29-16, 10:56 PM
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I'm gonna pop atop on a diet Coors beverage and watch for the out comith on this one LOL !!~!~~~!~!~!
 
  #20  
Old 03-31-16, 08:07 AM
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The oil doesn't smell like gas. Yes I can see the push rod coming up when rotate the engine. I will have to check the gap when i rotate it I just know it is correct at tdc
 
  #21  
Old 04-04-16, 12:36 PM
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If you have difficulty rotating the crankshaft nearing TDC, then you do NOT have a compression problem. I suspect you are not rotating the engine fast enough to fire properly. There must be enough velocity in the carburetor venturi to pull fuel from the float bowl, mix it and then send it into the combustion chamber.
Pull the dipstick and check the odor of the oil on the end. If it smells like fuel, I'd suggest changing the oil. If it smells of fuel, and is over-full, you may have flooded the crankcase with fuel. Change the oil if that is the case as the bearings don't last using oil diluted by gasoline.
tom
 
  #22  
Old 04-07-16, 08:46 AM
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Thank you i will look into it
 
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