Compression testing.

Troubleshooting, rebuilding, repairing Onan engines.
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Re: Compression testing.

Post by Eugen »

That right cylinder only went from 80 to 85 with the oil. May want to check the valves on it.
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Re: Compression testing.

Post by DavidBarkey »

Propane57 wrote: Mon Feb 14, 2022 3:12 pm So I did a cold test yesterday and both cylinders were at 80 psi or so. 4 pulses.
Today after throwing some snow, figured engine would be warmed up. Left cylinder at a little over 80 at 4 pulses almost 100 at 7 pulses. Right cylinder still around the 80 mark at 4 pulses and still around 80 at 7 pulses.
Any way. Worked good today.


Noel
Check the valve lash . On these flat heads as the valve and seat ware you loose valve lash . It might just need an adjustment . You will need to replace the tappet cover gaskets to do this or it Will leak . They are cheap , or you can make your own . You will need 3 total .

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Re: Compression testing.

Post by propane1 »

Well I look at that soon. I’ll have to figure out where to do this adjustment. Onan engines are new to me. So have to do figuring on it yet. Kohler's not so much, because I have six of them. And four that don’t run.
Is the way you adjust the valves similar to doing the kohler’s. In the manner how it’s adjusted. Hold one part and turn the other to make the adjustment.


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Re: Compression testing.

Post by DavidBarkey »

Propane57 wrote: Mon Feb 14, 2022 5:29 pm Well I look at that soon. I’ll have to figure out where to do this adjustment. Onan engines are new to me. So have to do figuring on it yet. Kohler's not so much, because I have six of them. And four that don’t run.
Is the way you adjust the valves similar to doing the kohler’s. In the manner how it’s adjusted. Hold one part and turn the other to make the adjustment.


Noel
Yes,
image.png
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oh ya intake gaskets
Also a good time to reseal the 2 piece intake while you have it off.


Dave
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