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Discussion Starter #1
I am a new tech at a rental yard and we have 15 pressure washers that all run fine. Since the season p/w'ing season is coming up, I though I would check out how they are all doing. Every single machine starts, idles, runs, and performs well. I checked the compression and all seem to be the same, 55-65 psi (at normal operating temp). I know they should be between 80 and 125 but if everything is running ok should I worry about cutting valves and replacing rings or not.

Honda 6.5 HP
 

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Compression

These unit probably have much higher compression, but your reading is at cranking speeds and the automatic compression release is most likely affecting your reading. If they all run, idle and perform alright, I would not worry about doing valve jobs on all of them.

If they are hard to start or have hot restart issues then maybe they should be checked.
 

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Discussion Starter #3
a few more questions.

Thanks for the reply, I was reading the service manual on for the GX160 Honda motor and it states that acceptable commpression is between 85 and 121 psi. In the heading of the column it says
""
Decompression Test
(Mechanical Decompression Enguaged)
85-121 PSI @ 600 rpm.
""

I looked throught the entire service manual and could not find a single thing that talked about where, what, or how to enguage or disenguage.

I followed the manuals instructions on how to check it but still get between 55-65.

I have checked compression before on other 2 stroke motors and got the propper result. What am I doing wrong, or are they all low?

If it helps.....
Most of these units are about 3 years old. Heads never removed, just general oil changes.
 

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Low Compression

These engines are 4-cycle engines, and with the age if they go out a lot, it could just be wear, most likely rings, but valves may need some attention also. Once again if they start easy, run and perform good and are not using excessive amounts of oil, then I would probably wait to do anything to them.

You might want to take a look at just one of them and see what you find. If replacing the rings and or working on the valves makes a big difference in the performance of that unit then you might consider doing all the units as well.
 

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30 yr. Tech gives excellent advice along with your own comments in the first post of this thread..."Every single machine starts, idles, runs, and performs well". If it ain't broke, don't fix it.
 
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