Hey! This site is reader-supported and we earn commissions if you purchase products from retailers after clicking on a link from our site.

If your Ingersoll Rand air compressor is bogging down, and you can’t quite figure out what the reason is, it can become very frustrating. Fortunately, this guide will provide you with the most common reasons why your Ingersoll Rand air compressor bogs down, along with existing reader questions and responses.

Table of Contents

Most Common Reasons Why Ingersoll Rand Air Compressor Bogs Down

Diagnosis of the problem may not always be so easy as there can be many things that can be the cause of the Ingersoll Rand compressor bogging down. However, here are 3 of the most common reasons why your Ingersoll Rand air compressor bogs down and runs slow:

  1. Additional power-drawing appliances
  2. Use of extension cord
  3. Faulty unloader valve

Additional Power-Drawing Appliances

Ideally, an air compressor should be powered from a socket that leads directly back to a 15 amp (minimum) or a 20 amp breaker or fuse at the panel. If other appliances are in the line that feeds the compressor, you should shut them all down before testing the compressor again.

Use of Extension Cord

If an extension cord or power bar is being used, you should remove it, and plug the air compressor power cord directly into the wall socket to see if that helps. This is because the extension cord or power bar will underpower the compressor.

Faulty Unloader Valve

The compressor unloader valve has likely failed – open the tank drain and let all of the air out of the tank to test this. This will emulate the unloader valve function, and at the same time, remove any water buildup inside the tank. Close the drain and power up the compressor to test. If the compressor starts easily and runs up to cut out pressure, it is now time to service or replace the unloader valve.

For more detailed information on this topic, visit our Air Compressor Bogs Down – Solutions & Diagnosing Problems guide!

Reader Questions & Responses

Ingersoll Rand Air compressor Keeps Bogging Down – Ingersoll Rand Air Compressor Troubleshooting

Question

The compressor unit will start and run ONLY if all the air valves are OPEN.

When the valves are in the closed position the unit will build 40-60 PSI before the unit bogs down to the point of shutting off.

The unit will not restart until all the air pressure has been bled out of the system first.

We are in a deployed location and do not have access to a Technical Manual for this unit. Any help would be highly appreciated. Thank-you

Ingersoll Rand 185 air compressor
Ingersoll Rand 185 air compressor

Response

So, if you get it started with the valves open, can you close it slowly – and does the engine rev at all? Is that how you get the 40-60 psi?

Main things (which I imagine you already checked)

Clogged air or fuel filter, low/bad fuel.

Linkage to throttle.

check out

https://www.sunflowerrental.com/files/Ingersoll-Rand-AC185D-Operators-Manual.pdf/

too.

Questioner

Hello Sir,

You are correct, we start the compressor with the valves open and the motor will run at high RPM, when as we close the valves (which would build up air pressure in the tank) you can hear the motor drop rpm as it builds this pressure to the point that the motor itself cannot maintain rpm nor idle.

The result of closing the air valves is the motor stalls.

The Air pressure being observed is about 60psi before the motor actually quits.

We have checked everything you described, and we don’t believe it’s a safety system triggering the stall because we are getting good constant power to the fuel pump, while replicating the stall condition we observe the voltage to the pump.

In short, at no point does the fuel pump lose power, so we know it’s not any system shutting down the fuel supply.

We have also pulled the unloader valve off to see if everything was kosher and it was clean.

Again any help would be appreciated, if you have questions we are more than happy to oblige.

Thank-you Doug.

Very Respectfully: John

Response

Well, first thing is that the engine needs more fuel as the load increases – and it’s not getting it.

  • Throttle linkage
  • Fuel rail pressure / volume (filters)
  • Bad fuel
  • Restricted air intake

That given that the air end is not suffering from bad bearings and binding as the pressure goes up.

Existing Ingersoll Rand P185 tow behind compressor pages:

If you have any questions regarding an Ingersoll Rand air compressor bogging down, please leave a comment below, with a photo if applicable, so that someone can help you!