912ULS maintenance

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Wagondriver

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I am looking at and probably going to buy a plane with two 912ULS engines on it. They have right at 1000hrs. What service items are coming up at 1000hrs? I can, and do, look these things up on the internet, but I am interested in hearing from people familiar with these engines.
Mechanical fuel pumps and fuel lines have been replaced at about 980 hours. They have been run mostly on unleaded fuel, but have seen some 100ll, but it sounds like only on long cross country trips.

What areas should I pay special attention to when I inspect it prior to purchase?
 
Wagondriver said:
I am looking at and probably going to buy a plane with two 912ULS engines on it. They have right at 1000hrs. What service items are coming up at 1000hrs? I can, and do, look these things up on the internet, but I am interested in hearing from people familiar with these engines.
Mechanical fuel pumps and fuel lines have been replaced at about 980 hours. They have been run mostly on unleaded fuel, but have seen some 100ll, but it sounds like only on long cross country trips.

What areas should I pay special attention to when I inspect it prior to purchase?
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Gearbox inspection on each and probably also due for carb clean and re-balance. Also look into if it was all the rubber hoses or just the fuel lines replaced. On your compressions - you’ll want them run at 87 instead of 80.
 
The serial numbers. Some early 912ULS' have a TBO of 1,200 and 1,500 hrs respectively. No worries on 100LL as long as it's run < 30% of the time otherwise more frequent oil changes should have been performed. As noted above gearbox inspection at 1,000 hrs so that will take care of any lead in it. Verify rubber replacement (coolant hoses, oil and fuel lines if not teflon, carb sockets, carbs, expansion back plate) was performed within the last 5 years.
 
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In addition to the above note about some earlier models having a 1200 hour TBO, there was an issue with the earlier models as well with case fretting which typically would cause the start of oil leaks around a thousand hours and there's really not any fix other than overhaul/replace. I think they fixed this problem in 2006 or 2007, but you would need to check with the case number to find out if it is a new or old design.
 
As noted, some of the early engines initially had a low TBO, but those have been "extended".
There are about a bazillion service bulletins issued by Rotax for this and that. You can look them up by serial number.
Useful resources - https://www.flyrotax.com/p/service/technical-documentation https://www.rotax-owner.com/en/
The engines are due for the gearbox inspection at 1000 hours.
If you see any signs of leaks, you have a problem. Look carefully. Any leak. There have been some case cracks on early engines.
The 912 ULS may or may not have the "slipper" clutch that protects the engine in the event of a prop strike.
Carb floats have been recalled many times. I have switched to the Marvel Schebler floats at 200 ****ing dollars for 4 stupid plastic pieces...
 
Engine serial numbers are 4425731 and 732, appears they are from last half of 1999. Which from my scratching the surface of 912 info means 1200 or 1500 tbo?, and not available for extension to 2000 hrs.

Carb floats were checked and weighed in one log book entry. Logs show friction torque checks at 38# in a recent entry.

What does a gearbox inspection cost? time to complete? How much cost for parts is involved in replacing all the rubber parts?

Thanks
 
Wagondriver said:
What does a gearbox inspection cost? time to complete? How much cost for parts is involved in replacing all the rubber parts?
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Hi.
The Gearbox is around $2600.00 to rebuild, if no complications. The time to test / rebuild is 5-600.00Hrs.
You can add to those the BRS, all the SBs, alerts,... some new ones just came up, you can end up with $11-12,000.00, if you have to do all, hoses, BRS,... annual.
The worst thing is that most mechanics are not qualified (know enough about it) to do the job, look first. Get informed in your area.

PS- There is a New owner, see: https://www.pilotsofamerica.com/community/threads/seek-input-on-buying-a-lsa.148631/, he went quiet after purchase, but you may want to see if it helps to get some info.
 
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Wagondriver said:
Engine serial numbers are 4425731 and 732, appears they are from last half of 1999. Which from my scratching the surface of 912 info means 1200 or 1500 tbo?, and not available for extension to 2000 hrs.

Carb floats were checked and weighed in one log book entry. Logs show friction torque checks at 38# in a recent entry.

What does a gearbox inspection cost? time to complete? How much cost for parts is involved in replacing all the rubber parts?

Thanks
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About the same vintage as mine and a few hundred more hours. But remember, TBO is not a real number.

Friction torque at the prop says you have the slipper clutch. Mine doesn't.

If the floats are still floating, fine. But they may yet decide to start to sink (engine runs rich). They are stupid easy to replace. Just expensive to buy.

One service center is estimating $800 for a gear box inspection. Of course, you would have to pull the gearbox and ship and it assumes gears, clutch, etc. are still good.

4 Stroke Gear Box Services - ROTAX Repairs - ROTAX Engines & Parts

Advanced Powerplant Solutions Online Store
www.advancedpowerplant.com www.advancedpowerplant.com
(They did a nice job on my water pump)

Personally, I don't get excited about replacing all the rubber on schedule. Cost depends - for example: actual official 17mm coolant hose is $100 per meter from the above source (you need 2m per engine), 5/8" coolant hose from an automotive source is a lot less (a bit tight, but works).
 
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