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Losing Power On Kohler


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#16 WNYTractorTinkerer OFFLINE  

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Posted August 25, 2013 - 10:50 PM

I understand that, my issue is with the accuracy of doing it that way. The variation could be caused by the compression release itself and have you wasting time trying to figure out a problem that is nonexistent. Or the compression release bleeding off pressure could mask any problem that did exist.

We hear ya AVB..  the Compression release is on both cylinders so it stands to reason you should get the same general compression reading between cylinders unless there's a problem..  It's just more of a general indicator of cylinder condition & uniformity than anything else..  See what we mean??  It is a good tool to try and diagnose trouble and rule things out is all..  


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#17 AVB OFFLINE  

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Posted August 25, 2013 - 11:11 PM

Yes, you should get the same general reading, but you could still get the same general reading while having a bent exhaust valve.


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#18 OkieGt OFFLINE  

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Posted August 25, 2013 - 11:37 PM

We hear ya AVB..  the Compression release is on both cylinders so it stands to reason you should get the same general compression reading between cylinders unless there's a problem..  It's just more of a general indicator of cylinder condition & uniformity than anything else..  See what we mean??  It is a good tool to try and diagnose trouble and rule things out is all..  

not sure y'all is cutting the same yard


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#19 WNYTractorTinkerer OFFLINE  

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Posted August 26, 2013 - 12:43 AM

So if you have a bent valve, wouldn't the compression on that cylinder be lower??  Maybe I'm spit balling here>>  But I'm pretty sure the reading in that one will be..  Cylinder includes valves AND piston?  Or do you remove the valves first before testing??  I got nothing else to say about this..  Ever..  I'm done..  Over!


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#20 AVB OFFLINE  

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Posted August 26, 2013 - 04:37 AM

It may or may not show up. Because of the ACR opening the exhaust valves at TDC it basically mimics a valve that isn't seating. That may be just enough to lower pressure in the good cylinder to match the one with the bent valve.

 

Say for example with the op's engine, Kohler says that engine should make 150psi with the ACR disabled and at least 90psi with the ACR enabled. Now lets say that the cyl. with the bent valve is only making 90psi to start with, the ACR may not open that valve any more than it already is. So you would still be getting 90psi on that cyl. Now say that the other cylinder would make 150psi with the ACR disabled, but with it enabled that cyl, is only showing 95psi. So you would have a cylinder making 55psi less than the other cylinder, but it is only showing up as 5psi difference in the test.

 

In those circumstances, based off the compression test, you wouldn't know that you had a vavle not seating.

 

I am just pointing out things that could happen and why I wouldn't trust the compression readings with the ACR enabled.


Edited by AVB, August 26, 2013 - 04:47 AM.

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#21 AVB OFFLINE  

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Posted August 26, 2013 - 04:46 AM

Another example could be made for head gasket issues. You could have a head gasket that leaks at 120psi, but holds at 100psi. If the ACR only let the cylinders make 90-100psi the blown head gasket wouldn't show up on a compression test.


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#22 HDWildBill OFFLINE  

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Posted August 26, 2013 - 09:23 AM

I think we need to get this thread back on topic and help farmer John get his tractor fixed.  I think we have discussed the pro's and con's of a compression test enough and I see this discussion going no where.  

 

Sorry Farmer John for hijacking your thread.


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#23 AVB OFFLINE  

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Posted August 26, 2013 - 05:14 PM

I am just waiting for an update from Farmer John to get us back on track.

 

When the engine loses power does it start smoking?


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#24 farmer john OFFLINE  

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Posted August 30, 2013 - 09:06 PM

thanks guys for all your help and ideas, i have been under the weather latley, pulled the fly wheel off and found the key had split, i ordered a new one and installed it this morning and after a little fudging, swearing and praying it fired up, will continue putting it back together tomorrow if my back holds out


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#25 OkieGt OFFLINE  

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Posted August 30, 2013 - 09:10 PM

thanks guys for all your help and ideas, i have been under the weather latley, pulled the fly wheel off and found the key had split, i ordered a new one and installed it this morning and after a little fudging, swearing and praying it fired up, will continue putting it back together tomorrow if my back holds out

Check Those Valve Clearances!!!!



#26 HDWildBill OFFLINE  

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Posted August 30, 2013 - 10:06 PM

Glad you found the problem and hopefully your back will feel better tomorrow to finish up.



#27 AVB OFFLINE  

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Posted August 30, 2013 - 10:36 PM

Good to hear, hope you feel better tomorrow.






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