[June 11, 2024]

My Slick 4371 Impulse Coupled magneto is long overdue to replacement. I did some of the 500 hour work myself, but I felt like I was on borrowed time with it after 970 hours. A few years ago I bought a used set of mags with about 500 hours on them. I sent in the 4371 to Aircraft Magneto Service in Montana - this shop came highly recommended to me from multiple friends and A&P's. They quoted me somewhere between $400-$1200 to fix the mag sight unseen - when I received a call from them the price was $500 to fix shipping which sort of made my day. New mags are around $2k!

Tonight I started the process of replacing the mag. With the cowling off, I measured the resistance of my emag ignition wiring harness.

Nowadays you can't buy an EMag harness you terminate yourself - they come pre-made. But when I built my RV-7 you could buy a set of plug you could customize the length to. The original spec for resistance was 180 Ohms/ft, which all of mine seemed to be around. However, the new pre-terminated wiring harness was 40 Ohms/ft, so since I needed to put in an order to ACS I tacked on new ignition wires.

(Source https://vansairforce.net/threads/emag-harmess-resistance.220873/)

I removed the old magneto and also the fuel pump. Why the fuel pump? Well a while ago I was having intermittent low fuel pressure readings when on the engine driven pump with the electric pump off. I thought it was a fuel pump failing, so I replaced it and added a cooling shroud. This didn't solve my low pressure readings and I just sort of ignored it since I knew it wasn't fuel pump or plumbing related.

I never really liked the cooling shroud. I felt like I could never really get the nuts of the fuel fittings in and out of it tight, or get a good visual inspection of it.

With the magneto removed, it was very easy to access the fuel pump. I wish I removed the mag when I originally replaced it - it's so much easier to access with it off!

Old magneto removed - I will send this one in to get serviced.

The fuel pump removed.

The new mag. This should be ready to be installed once I get some parts from ACS to reinstall the fuel pump.

I didn't like the condition of the O-Rings on the fittings into the fuel pump - the proper replacement O-Ring p/n is: MS29512-06

Source: https://vansairforce.net/threads/for-the-true-gurus-what-is-this-o-ring.184730/



Last Modified: June 24, 2024