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Propeller Blade Mounted Magneto Timing Device

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Part# 12-04969


The propeller blade mounted timing device is a self-contained unit that incorporates the blade mount, digital inclinometer, and adjustable cinch strap. More accurate, quicker, and easier to use than competitive products. The blade slots are graduated and spaced so as to allow installation on many different blade model designs.
California Prop 65 Warning Symbol

WARNING: Cancer and Reproductive Harm -



White B Verified Purchase


June 12, 2023

After years of messing around with the flower pot hanging onto the prop hub and hoping the weighted needle indicated correctly, this digital inclinometer was a breath of fresh air. Incredibly accurate and reliable. If you regularly do mag-to-engine timing (specifically continentals), this product is the only real way to go.

Ken P
April 30, 2023

Curtis J Verified Purchase


January 5, 2023

Does this work for geared engines. We recently worked on a Cessna 421 with GTSIO-520-H engines

Christopher T Verified Purchase


March 31, 2022

nice simple and accurate tool!

Ken K
August 27, 2020

It works great. Very accurate. Improved my speed and quality. It fits every airplane Ive put it on so far. Done a 1947 aeronca scout and a 180 hp 172 1974. So far. Just in the first week. Its paid for its self.

Mike S
August 5, 2019

I bought this unit to double check a problem I was having with my Lycoming. Im very meticulous with mag timing. Anyway, the unit worked very well. Yes, I have heard of people saying they can use their smart phones to do the same thing. But you still need a solid plug for your spark plug hole. The prop mount fit my sensenich prop very well. THeres no doubt there is considerable profit margin on this set up, but I gave it 5 stars because it is something I probably couldnt make (I dont have a machine shop that nice nor a 3-d printer). I like it far more than the flower pot we use for continentals. For Lycomings....if You can see your starter index, you can still do a great job timing that way. With this unit, you dont have to remove the front cowl though. Trying to time using the top case half just isnt all that accurate in my opinion (from the back side). This unit takes all the guess work / slop out.

June 10, 2019

Ive timed engines using the taped on digital protractor. If your time is worth anything to you and if you actually work on doing this often, you will appreciate the difference and time saved.

Richard B
November 5, 2017

I just got this and it works very well. The plastic mount needed some trimming to make the digital protractor fit and I chamfered the edges to alleviate the possibility of scratches when attaching it to the propeller blade. It would be nice if the protractor didnt auto shut off.

John D Verified Purchase


February 2, 2022

One guy said you can hold a timing device on with rubber bands or tape. You can, but this works so much better. Ive timed engines using a taped on digital protractor. If your time is worth anything to you and if you actually work in a shop doing this all day, you will appreciate the difference.

October 31, 2017


Please note, Aircraft Spruce'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 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 the Propeller Blade Mounted Magneto timing device register a full 180 or 360 degrees or does it reset at 90?

Per Vendor: The device follows a 90 degree rotation. So as you turn and reach 90 degrees if you were to continue it would count from 90 back down to 0. That is why I provide a special length timing stop pin with the kit that will keep everything in a 90 degree fan.

Q: Does the Propeller blade mounted timing device work with 3 bladed props?

Yes this will work with a 3 bladed prop.

Q: Does it come with cylinder plug? Whats in the kit?

Yes, per the instructions the piston stop pin is included.

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