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Part# 12-03330
MFR Model# 2EM-KIT


Paired together is the line ATS 2EM Differential Pressure Tester (with Master Orifice) along with the Spark Plug Port Extension Tool to make maintenance a whole lot easier.

Protective form-fitted hard case included.

NOTE: The ATS 2EM Differential Pressure Tester has a .040 orifice as required by Teledyne Continental SB03-3 Service Bulletin, and is the proper type of instrument to test ALL Teledyne Continental engines in accordance with the aforementioned bulletin. The ATS 2EM also complies Textron Lycoming SI-1191A Service Instruction and is appropriate for ALL Textron Lycoming engines as indicated in the Service Instruction.

In The Box

  • 1 - ATS 2EM Differential Pressure Tester (with Master Orifice)
  • 1 - Spark Plug Port Extension Tool
  • 1 - Protective form-fitted hard case
  • 1 - 18mm adapter (for extension & tool)
  • Accessories
  • Customers Also Viewed
  • Frequently Purchased With


Excellent product!

Louis B Verified Purchase


August 9, 2021

Quality product that works very well. The hard case keeps everything safe and together between uses. I hope my Wife appreciates the new air compressor shes getting for her birthday!

August 31, 2020

Nice piece of equipment

Rob B
August 21, 2020

Certainly a better compression tester than others I have used in our shop in the past

John H
July 28, 2020

So easy to use. The included storage box is handy too.

Cowans A
July 14, 2020

Worked great. Reliable and repeatable readings. The case is a nice addition to store and carry the unit. The extension also made the job easier. I learned that if you set the cylinder at exactly TDC, the compressions reading can be done by one person. If not, another person is needed to hold the prop from turning backwards due to the pressure. This could have been explained by the directions...

March 19, 2020

Quality tester, nice to have the Master Orifice Valve to check the accuracy of the gauge. I vae seen many testers where the actual gauge is reading way off. This one so far is accurate as hell.

Vincent C
May 4, 2019

Super pleased with this purchase and I havent even used it yet. Could not beat the price and I need not comment on the super service I have always gotten from Spruce. The quality of the tester (I did fire it up with my compressor) is excellent and the inclusion of the Extension Tool was just icing on the cake and will be a great help during Annual. The case holds the tool and has a captive slot for the extension as well as an extra spot for a different sized plug adapter.

Hr M
February 3, 2019

The kit arrived on time and in good condition. It is nice to have both the standard plug fitting for tight spaces and the extension tool for longer reach. The hard case is durable and has snap-in recesses for the various parts to hold securely. The instructions were clear and succinct. The tester worked as intended and was easy to use. Would definitely recommend to others.

John M
May 14, 2018

This compression tester does the job just fine. The extension helps on some engines where baffling and wiring makes the plug hole difficult to get your fingers to to install the normal plug adaptor.

Lloyd A
May 10, 2018


Please note, Aircraft Spruce Canada's personnel are not certified aircraft mechanics and can only provide general support and ideas, which should not be relied upon or implemented in lieu of consulting an A&P or other qualified technician. Aircraft Spruce Canada assumes no responsibility or liability for any issue or problem which may arise from any repair, modification or other work done from this knowledge base. Any product eligibility information provided here is based on general application guides and we recommend always referring to your specific aircraft parts manual, the parts manufacturer or consulting with a qualified mechanic.

Q: Does this ATS Pro Differential Pressure Tester include the flex tube connector? The photo just shows the T handle and gauges.

Yes, the kit does have the flex hose in the box.

Q: Does the ATS Pro Differential Pressure tester come with a current calibration?

Yes all units come calibrated.

They calibration is due 1 year after purchase unless the unit is dropped or grabbed by the gauges which could throw off the calibration of them.

Q: Does the ATS Pro Differential Pressure Tester #12-03330 include an adaptor for the 12mm x 1.25mm spark plug threads of a Rotax 912 series engine?

12-03330 does not include the Rotax adapter. Nor will the adapter thread onto this unit. 12-00693 does include the adapter. However it does not come with the extension that 12-03330 includes.

Q: Does it comes with a ATS Pro Differential Pressure Tester Kit calibration certificate?

Yes, per our notes, the calibration card is included.

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