My "scrap" 912uls

[napierm]

So last fall I bought a 912uls "for parts". Had to drive up to Minnesota to get it. The old engine was in the crate that the new engine came in. The were a few pieces that came with the new one including a new oil tank. It was sitting beside the plane, a Searay.

The story was that the engine got to where it wouldn't start. They said the word from the local Rotax shop was that the too heavy prop had damaged the gearbox to the point that the small gear in the gearbox had spun on the crankshaft. The partners in the plane had elected to buy a new engine and put on a lighter weight prop. I bought the crate as a box of parts. Maybe I could make something of it else sell the parts.

At the time I talked to Hal Stockman and just said I had a motor with a bad crank and what would it take to fix. We talked a few options.

Well today I called again and described it in more detail. He said to take it apart myself and look to see how bad it was. So this afternoon I blew off work and got the rear housing off. That was easy sense the shop had been in there and everything was loose. The sprag clutch is gone so I'm guessing it was bad. The mating surface on the gear looks just fine.

Got the magnetic plug off. Hard to do, really had to work to get it off, old style. Shop sure hadn't touched it. Not too much stuff on it, maybe 1.5 mm. Then I got the gearbox off. Hard to do. All the screws were tight and I'm sure I was loosening Loctite. Had to really hammer with the slide puller to get the gearbox off. I think the sealant was fresh. Then the big finish: took off the big nut and small gear. The spines in the gear and on the crankshaft are perfect.

It doesn't look like the gearbox was taken off at all. The only thing wrong was probably the gearbox dogs and the sprag clutch. I'm going to replace the gears and inner dogs in the gearbox. Plus the sprag clutch. Looks like ~$2500 for everything.

Hard to say what the deal was with that shop. Miscommunication? The logbook shows a little over 1200 hours and the engine worth much more than I paid for it.

So next purchase is a motor mount from Kitfox.
:)

[WWhunter]

You made out much better than a friend of mine. He did the opposite....purchased an engine from Georgia (?) and had it shipped to MN. He paid a high price that was supposed to be "a great running engine". Well, the engine was total junk. Needs a total rebuild. His build has now been put on hold due to the unexpected financial hit.

The seller refused to even reply to any of his calls/ texts/emails. Con artists are out there guys!! In the end, he will have as much or more than he could have purchased a new engine for. The worst part is, my friend is one of the nicest guys you could meet, not one that would do someone wrong like has been done to him. If I can get the name of the seller, I will post it.

[109JB]

Bought a 700 hour 912UL and did the simple Rotax prop strike check, gave it fuel and it runs like a top. Price $5101.00, but it had a Kitfox IV Speedster attached to it that had just a few bent fuselage tubes.

[napierm]

Out of curiosity, does your speedster have short wings?

I have a part of short wings from a speedster that could be covered and flown. I do want to replace the tanks at least. Also have a pair of 3 wings that could be taken apart and rebuilt as 4 wings. A lot of work and some $$. Can make the ribs, attachments, etc. But would need tanks, flapperons, leading edge, hardware.

Honestly the plane is just about as fast and certainly more versatile with the longer wings.

But would be nice to finish it while I'm still alive.



Bought a 700 hour 912UL and did the simple Rotax prop strike check, gave it fuel and it runs like a top. Price $5101.00, but it had a Kitfox IV Speedster attached to it that had just a few bent fuselage tubes.

[atosrider]

some installations of the 912 delivered an unexpected surprise one day, after any amount of use and time, one day the #4 cylinder filled with oil since the last run, and that makes it impossible for the starter motor to turn it over .. a very expensive mistake, not following the manufacturers recommendation - spin the prop until you hear the burping delivery into the reservoir, before touching the starter .. I've rarely seen other 912 users do this pre-start procedure ...

[109JB]

Out of curiosity, does your speedster have short wings?

I have a part of short wings from a speedster that could be covered and flown. I do want to replace the tanks at least. Also have a pair of 3 wings that could be taken apart and rebuilt as 4 wings. A lot of work and some $$. Can make the ribs, attachments, etc. But would need tanks, flapperons, leading edge, hardware.

Honestly the plane is just about as fast and certainly more versatile with the longer wings.

But would be nice to finish it while I'm still alive.

Yes it has the short wings. It will fly that way initially, but I may build a set of extensions for it to make it the same span as the standard Kitfox 4. I have some parts off of a wrecked Kitfox 4 wing and there is enough there to be able to make extensions.

[efwd]

some installations of the 912 delivered an unexpected surprise one day, after any amount of use and time, one day the #4 cylinder filled with oil since the last run, and that makes it impossible for the starter motor to turn it over .. a very expensive mistake, not following the manufacturers recommendation - spin the prop until you hear the burping delivery into the reservoir, before touching the starter .. I've rarely seen other 912 users do this pre-start procedure ...


I spin my prop after flying and before leaving the hangar. I check the oil level before flight. It is far easier to spin when oil is thin. I specifically asked my Rotax mechanic about this and he told me that I was fine. If I learn otherwise by cranking on a full cylinder I will be unhappy.

[jrevens]

I have been doing what you do too, Eddie. I’ve been thinking lately though that it might be better, especially under certain circumstances, to only turn the prop right before running the engine again. My thought is that when the engine is shut down there is a lot of oil up in the engine itself, coating the cylinder walls, etc. By turning it to “burp” you’re scraping oil off of the cylinder walls and moving oil out of the engine. I suppose it probably doesn’t make much difference, especially if you fly real regularly and/or live in a dry, ocean-air free climate. If you end up not flying for a few weeks or months, it might be better if the engine was left undisturbed. Then again, maybe not. I’m just brain-storming here (& it’s a very small “storm”).

[jiott]

I was doing the same thing and then stopped doing it for exactly the reasons you mentioned John. I agree that if you are flying regularly it probably doesn't matter, but in the winter when it may sit for many weeks I think it does matter.