912ul Pierburg fuel pump FAIL

[dholly 718]

Man, I am getting dejected this year. Seems every time I go to fly something else breaks and cuts the fun short. So today I notice fuel seeping from one of the weep holes on my fuel pump. If I understand correctly, this particular weep hole will identify a bad diaphragm. Which is not a replaceable rubber so a whole new pump is in order. Just when who knows how many 912ul and 012uls owners are facing a mandatory fuel pump Service Bulletin and clamoring for the part. Last I heard the lead time was 3+ weeks not to mention the RoTAX $$$... grrr.

[Av8r3400 1179]

I don't feel sorry for you.    

 

I'm down for what looks like 2 months waiting on gearbox parts from Austria...  I can't even steal parts from the Mangy Fox because that has a different gearbox!

[dholly 718]

-ouch- I feel a little better now, curious what parts did you have to order?

 

BTW, I saw your comment about the replacement engine mount rubbers and bushings. I bought them from Kitfox early this year too but, after reading what a PITA it is to swap them out, haven't tackled it yet. This is one of the items on the Rotax 5-year rubber replacement schedule and I suspect you would find some benefit even if it isn't the primary source of your vibration. I've also heard you can flip the donuts over to buy a little more time when you notice uneven compression. Either way, it would keep you busy while you're waiting eh?

[C5Engineer 1170]

Larry you could always swap in a 582     Just kidding. At least you guys are not having issues while in the air! Please continue to keep your 912 threads updated. I would like to get some more 912 tech data on the site and I think you guys are pretty much our only contributors to that area.

I don't feel sorry for you.  

 

I'm down for what looks like 2 months waiting on gearbox parts from Austria...  I can't even steal parts from the Mangy Fox because that has a different gearbox!

[Bandit 286]

Or a 503! You just plug and play.

[EDMO 1078]

Or a 503! You just plug and play.

Bandit,

Got to give you a big "High-Five" on that - Cant argue with success!

EDMO

[Av8r3400 1179]

The gear set and dog hub.  I believe this is a function of that heavy-assed Warp Drive prop...

 

In a 912 there are two types of gears, 22mm and 27mm wide.  My yellow plane has the 22mm set and the Mangy has the 27mm.  As luck would have it, a 27mm set can be replaced with a 22, but not the other way.

 

-ouch- I feel a little better now, curious what parts did you have to order?

[dholly 718]

Can't just swap the whole gearbox rather than just the gear set and dogs?

 

Now I got to look to see which gear set I have. http://www.conairsports.co.uk/4-stroke%20gearbox.html

[Av8r3400 1179]

No.  The crankshaft on my Yellow plane is such that only the 22mm (narrow) gears will fit.  The gear set in the Mangy Fox is the newer design 27mm (wide).

 

Good link.  Lots of good information there.

 

The reason for replacing the parts is when I did the disc spring replacement I noticed wear in the form of spauling on the drive dogs.  In my opinion it was very minimal and the consensus of my group was to put it back together and run her.  Well the vibration was just as bad after the "repair" so I did some further investigation.

 

Speaking directly with John McBean he noted the need to modify the engine mounts per SA 53A (?) but he also related a story about a gear set problem like what I am having.

[dholly 718]

Back to the fuel pump replacement.

I should mention that the latest 912 fuel pump version is p/n 893-115. This is the basic, bare pump only and normally runs $175 or so at the 'big 3', add another $30 for the inlet and outlet nipples sold separately + S&H. However, because of the recent mandatory service bulletin on 912 fuel pump replacement, Rotax is making available a discounted replacement pump 'upgrade kit' for a limited time. You don't have to have a pump within the affected s/n's in the SB to get the discount.

The upgrade kit is p/n 881-360 and includes the fuel pump with o-ring and flange gasket, fuel line nipples, crush washers, (2) each new mount hex nuts and lock washers, and (4) ear clamps to reattach the fuel lines and fire sleeve. Cost was $98.00. If you have a SLSA, I believe Rotax is also offering a substantial discount on the replacement fuel pump assembly (p/n 892-546 pump w/ pre-attached pressure and suction hoses, part of the mandatory 5-year rubber replacement maintenance) 'upgrade kit' as well. This kit cost $155 vs. $500+ normally.

FWIW, Rotax has a 5-year replacement requirement for all 912 fuel pumps. If you are an ELSA timed out, previously balked at replacing a perfectly good working pump, choked on the cost involved in compliance or whatever etc., here's an opportunity to get one at a 50% discount or perhaps buy a spare. I ordered a second pump for the rubber replacement on my Aerotrek due next inspection.

[SuberAvid 617]

Don't you just love being held hostage by Rotax?

[dholly 718]

No, and there is a high probability that I will be moving the Aerotrek from SLSA to ELSA after the next inspection.

[SuberAvid 617]

Having an ELSA with the repairmen's certificate is the best IMHO.  Even an SLSA appears to be too much like a certified aircraft.