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Emglo Air Compressor Won’t Reach Cut-Out Pressure

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Is your Emglo air compressor struggling to reach cut-out pressure? And you’re unsure how to diagnose and fix the problem? Well, fear no more! This article will provide you with all the relevant information on why your Emglo compressor can’t reach cut-out pressure, including troubleshooting steps to follow!

Table of Contents

Why Won’t My Emglo Air Compressor Reach Cut-Out Pressure?

The most likely reason why your Emglo air compressor is not reaching cut-off pressure is due to failing or compromised parts. These can be summarized in the following table:

Head gasketIt is very possible that your Emglo compressor appears to be building pressure fine, but at some point during cycling, the pressure stalls and the air is unable to flow into the tank due to a failed head gasket.
Intake valveIt could also be a failing air intake valve, causing the air to blow right back out of the intake valve instead of being properly drawn into the compressor.
Piston sealIf the piston ring seals are not working as they should, the pumps will lose significant pressure and efficiency, resulting in a lack of pressure being built in the compressor.
Pump pressure valveThe pump pressure valve could be faulty, allowing air that flows into the tank through it to be drawn right back out of the tank.
Reasons Why Your Emglo Air Compressor Is Not Reaching Cut-Off Pressure Table

Other possibilities include leaks in various parts of the system. So, if your Emglo air compressor won’t reach cut-out pressure, you should be able to diagnose and fix the problem by following these troubleshooting steps:

  1. Conduct a pump-up test
  2. Inspect system for leaks
  3. Clean filters
  4. Inspect system valves
  5. Evaluate belt condition
  6. Inspect pump rings
  7. Inspect air/oil separator

For more detailed information on each of these Emglo air compressor troubleshooting steps visit our Air Compressor Won’t Reach Cut-Out Pressure Troubleshooting guide!

Reader Questions & Responses

Emglo Compressor Does Not Reach Cut-Out Pressure – Emglo Air Compressor Troubleshooting


My Emglo k15a-8p turns on but does not seem like it is running full speed.

it builds pressure slowly and only up to around 80psi. I think it is set up as a constant run as when it is full of air, it still runs, but something happens and it runs much quieter.

Now the compressor runs in this “quiet” state all the time. any ideas?


I searched for an Emglo with your part number and found one with the same model number by Jenny. Is this Jenny shown below the same as your compressor?

Jenny K15a-8P air compressor
Jenny K15a-8P air compressor

Constant run compressors have valves that control the intake. When the pressure in the tank reaches cut-out pressure, then that valve opens, unloads the compressor, and the electric motor can run with almost no load, saving wear, tear, and energy costs. Typically this scenario works for liquid fuel-driven air compressors or the bigger rotary screw / rotary vane type.

If your compressor only runs “unloaded”, then likely you’ve got a problem with the unloader circuit.

Emglo Compressor Won’t Reach Cut-Out Pressure – Troubleshooting Emglo Air Compressor


AM78HC4V has air leaking out of the dipstick

Emglo AirMate AM78HC4V has air leaking out of dipstick bypass holes.

The compressor will not build more than 30 psi.

AM78HC4V has air leaking out of dipstick
AM78HC4V has air leaking out of the dipstick


Well, the symptoms indicate that your Airmate has some pretty maintenance-necessary issues.

The combination of air blowing out of the oil fill tube bypass and the fact that the compressor isn’t building pressure past the 30 PSI point combine to make me think that this compressor has some badly worn piston seals.

Sure, overfilling the oil could allow a little oil out the fill tube vent holes as the sump ventilates as it is supposed to, but if you are feeling or seeing the evidence of a lot of air, then it’s time to tear down the pump and check the cylinder walls, pistons, and replace the piston seals, intake and pressure valves and any gaskets.

If you have any questions regarding why your Emglo air compressor won’t reach cut-out pressure, please leave a comment below, with a photo if applicable, so that someone can help you!

By Aidan Weeks

A passionate Mechanical Engineer with endless enthusiasm for fluid power - building off the back of over 18 years of high quality contribution and discussion stimulated by Bill Wade here at About Air Compressors. With both practical and theoretical experience in pneumatics and hydraulics, I'm putting my knowledge to work - and working my grey-matter through my research, assistance and publishing work here at About Air Compressors. Feel free to reach out any time! P.S. A HUGE shout out to Doug who really offers such great value to all visitors to About Air Compressors - once again, feeling like I'm standing on the shoulders of GIANTS by getting to work alongside such a great community

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