JD 3020 Compression Test

Bruce C · Apr 18, 2015

I have a 1971 JD 3020 I did a compression test on. The service manual calls out for 180 psi at 170 RPM. Is that the RPM the starter will turn the motor over? I did the test with a cold motor and was getting between 116 and 122 psi. Is it better to perform the test after the engine has warmed up, or does it matter?

Kent Petersen · Apr 19, 2015

i think you need to re sleeve it and do a good job on the valves most likely needs new valve seats to

Tech 7 · Apr 19, 2015

I would destroke the front pump and redo the test with a fully charged battery to give a more accurate result. Or you could just sent it here LOL

Bruce C · Apr 19, 2015

Thanks Kent. I read some of the forum questions on carb problems with the gas 3020. Seems they can run lean and need valve work, sleeves or both every 2000 hrs. Mine has about 3600hrs on it. Thanks for the help

Tx Jim · Apr 19, 2015

Did you have throttle in wide open position when you tested the compression?

Bruce C · Apr 20, 2015

No I did not. That makes sense when you consider air flow into the cylinder. Will try that today and let you know.

JD 3020 Compression Test

Bruce C

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Kent Petersen

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Tech 7

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Bruce C

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Tx Jim

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Bruce C

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