Dan Langhout
Well Known Member
So I am about out of ideas. I have an Aero Sport Power IO-375 (Precision Airmotive Silverhawk FI / Lightspeed electronic ignition top and Slick impulse mag bottom) with almost 600 hours since new. Oil consumption rate has never been great (~ 7 hr/qt at best) and in the last year or so it had increased to 3-4 hrs/qt. I decided that at this annual, I would replace the ECI Nickel-Carbide cylinders with genuine new Lycoming Nitrided cylinders. Did the cylinder swap and now have about 11 hours on them - all following the recommended break in protocol (75% power etc, etc.)
Problem is, ever since the cylinder swap, The magneto really doesn’t pass a mag check at full rich mixture. EGTs all climb, but can be erratic. This is a change from the previous 600 hours. Leaning the mixture improves it significantly. In flight mag checks look good. The engine runs fine on either ignition (at least as well as any engine runs on one ignition). Of course the mixture is leaned normally during the in flight check.
Given that the mag check on the Lightspeed was still fine, I made the assumption it was some sort of mag ignition system issue. Short version is after swapping plugs, a new ignition harness, and even swapping out the mag, the issue is still there. Lower plugs basically come out black and somewhat wet looking.
Beginning to think the problem may be with the Silverhawk injection running too rich under typical run-up/mag check conditions - but that would certainly be a big co-incidence in that it just happened to develop the problem at the same time as the cylinder swap.
In looking for what items were “touched” during the cylinder swap, all spark plugs and leads were obviously moved, and the individual injectors and injector lines were removed and re-installed. If trash got into the injectors while they were out, I would expect lean issues - not rich issues. The magneto itself and the rest of the injection system were not touched (other than removing the “snorkel” where it bolts to the front of the fuel servo).
My next steps will be to do some of the recommended trouble shooting procedures for RSA type injection systems (injector volume flow test, etc.) but failing that - I am at a loss.
Any ideas?
Problem is, ever since the cylinder swap, The magneto really doesn’t pass a mag check at full rich mixture. EGTs all climb, but can be erratic. This is a change from the previous 600 hours. Leaning the mixture improves it significantly. In flight mag checks look good. The engine runs fine on either ignition (at least as well as any engine runs on one ignition). Of course the mixture is leaned normally during the in flight check.
Given that the mag check on the Lightspeed was still fine, I made the assumption it was some sort of mag ignition system issue. Short version is after swapping plugs, a new ignition harness, and even swapping out the mag, the issue is still there. Lower plugs basically come out black and somewhat wet looking.
Beginning to think the problem may be with the Silverhawk injection running too rich under typical run-up/mag check conditions - but that would certainly be a big co-incidence in that it just happened to develop the problem at the same time as the cylinder swap.
In looking for what items were “touched” during the cylinder swap, all spark plugs and leads were obviously moved, and the individual injectors and injector lines were removed and re-installed. If trash got into the injectors while they were out, I would expect lean issues - not rich issues. The magneto itself and the rest of the injection system were not touched (other than removing the “snorkel” where it bolts to the front of the fuel servo).
My next steps will be to do some of the recommended trouble shooting procedures for RSA type injection systems (injector volume flow test, etc.) but failing that - I am at a loss.
Any ideas?
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