Oil Injection System

Having just completed an awesome day of flying with Dean Turner and his Significant Other Carrie, I headed for home at Mach 1 to find a fellow flyer from UI, chapter 41 waiting at my hangar. Awaiting me with a big smile was Tim Hannagan. I had finished rebuilding his 582 Rotax and he was chomping at the bit to pick it up. We drove the short distance back to my house. As I showed him his now shiny engine and all of the old parts I had recently replaced, it dawned on me, that I have had to repeat this next line all too often lately. “This was an accident waiting to happen”, brings shiver up your spine doesn’t it, and it should. This bring me to the point of this short “I hope” story. Ultralighting is a glorious experience and with the freedom imparted upon us within Part 103, it would seem like we have the best of both worlds. However as with most freedoms there comes a responsibility. That responsibility is much heavier than we may at first suspect. This means we ultralighters, unlike any other segment in the aviation industry control or own destiny so to speak when it comes to airframe and engine maintenance. This is a very large responsibility! Part 203 assumes that the owner/builder is capable of maintaining his/her engine and airframe’s mechanical integrity. This may not necessarily be true. Not everyone is mechanically inclined enough, or has the knowledge and special tools required to properly maintain their own engines and airframes. Some of the best pilots in the world have “no clue” when it come to airplane maintenance. That is exactly why GA aviation requires “annuals”. My point in the following pictorial of engine photos is to simply make everyone that flies aware that if in doubt, PLEASE ask before embarking on unknown and unforgiving territory. There are a wealth of diverse skills and information available in most every club. That is just a small part of what makes joining a club so special. These photos are from Tim’s engine, the engine had 250+ hours on it and it was in need of a rebuild.

The oil injection system had been removed and the oil lines had been plugged with a wire! These must be air tight! The bottom end of a two stroke engine must not have any air leaks or the fuel air ratio will not be correct, an air leak here will eventually lead to an engine seizure. If you look at the next photo you will see an aluminum cover plate has been fabricated to cover the hole where the oil injection pump was originally mounted. The potential problem is not with the cover it is the lack of a gasket under the cover! The photo clearly shows the fuel oil mixture that has been leaking out of this cover.

Since on a 2 stroke engine alternately, both positive and negative pressures are present in the crankcase. If fuel oil mixture leaks out air will leak in. Piston seizures will result and the pilot’s day will be ruined. This next photo is of the oil injection pump I installed at time of rebuild and you can clearly see it has o rings on it to seal the cover.

The pistons shown below had heavy carbon buildup after 250 hours with premix and the rings were stuck, the piston skirts were collapsed and the clearance pis/cyl was .013”

It was definably time for new pistons, seals, and gaskets. These are just a few examples of the problems I have encountered while either rebuilding engines or looking at other airplanes at events throughout the country. The intent of this article is to open a few eyes and make everyone ask questions. Remember informed pilots make better pilots. Remember if a Rotax engine is properly maintained and stored, it will provide many hundreds of trouble free hours of flying.