New Rotax fuel pump and Running mods

[roger lee]

New Rotax fuel pump.


http://www.rotax-own.../item/4-newpump


New Rotax Service Instructions on running modifications.

http://legacy.rotax-...-912-020-r5.pdf

[Jack Tyler]

Roger, I know you are quite familiar with the Rotax USA distributors, and I'll soon own one of these engines. Can you help us better understand how they conduct their business here in the U.S.?

Here are a couple of forum comments on the Rotax website, related to the latest 'new fuel pump', that help frame a context for my Q:

"Flight School: We had the old fuel pump fail with 350 hrs. The rivet that holds the diaphram came loose and the engine quit on takeoff. Fortunately no serious injuries only a totaled aircraft. About time they came to the plate and changed the design. Notified Rotax the quality control was lacking, never heard from anyone?"

"About time! After replacing three due to leaking within 100 hrs. each I finally got tired of buying those and went for a Billet pump which works like a charm!"

Here's an observation from a very experienced DAR about this announcement:
"For What It's Worth...I have a friend who has been running a Rotax 912 on a Zenair Zodiac since about 1995. He has replaced more than a few engine driven fuel pumps. Several times he has been told, "This new design pump shouldn't fail!"" (Thread is at http://www.vansairforce.com/community/s ... hp?t=66775)

There are always two sides to every story. The problem seems to be that those representing Rotax in the USA are not very adept (or is it willing?) to telling their side. Why do you think there are so many negative comments about both the hardware (of what is now quite a mature design) and the responsiveness to QA issues from the Rotax presence here? Is it as simple as there not being in unified 'national presence' here, only individual distributors who are limited in how they can represent their European parent? What is it 'we' as customers/owners don't get...and what is it Rotax doesn't get?

Many thanks,

[drseti]

"Flight School: We had the old fuel pump fail with 350 hrs. The rivet that holds the diaphram came loose and the engine quit on takeoff. Fortunately no serious injuries only a totaled aircraft.

I don't know what kind of aircraft that was, so of course I don't know if the following will apply. But, in my SportStar, there is an electric boost pump in addition to the engine driven mechanical pump. One should always use the electric pump on takeoff, if so equipped, and keep it on until reaching an altitude sufficient for either turn-around or engine restart, should the mechanical pump fail. That can prevent totaling an aircraft when (not if, but when) the mechanical pump fails. Regardless of the design, when fuel pumps fail, it's generally on takeoff, a couple of hundred feet in the air, with no runway remaining ahead. Redundancy is two of your best friends!

FWIW, there are four times I use the electric fuel pump: (1) for engine start, to pressurize the fuel lines, float bowls, etc. (2) for every takeoff. (3) whenever changing fuel tanks in flight, to avoid engine sputtering due to air bubbles, etc. (4) for every landing (since landing approaches are just a setup for a go-around).

[roger lee]

Hi Jack,


Rotax has been having issues with these pumps since changing mfgs back in 2006. Rotax is more than happy to replace any damaged fuel pump under warranty as long as the engine is registered and still under it's warranty period (18mo from date of sale or 2yrs from date of engine mfg.) also the total time on the engine must be under 200hrs, and this needs to be verified with a photo copy of you latest logbook entry. The Pierburg pump which looks like the AC pump has worked well, but Rotax wanted an all new design. Rotax ask for different pump Mfg's to send in as many as 20 samples each and has been testing for quite a while. Rotax knew the AC pump needed changing. Regardless of what people think Rotax usually stays on top of things. People will complain, but they don't know what's going on behind the scenes. Testing takes a lot of time as several engines need to run for extensive times to test new parts. The Rotax 912 series engine is a good dependable engine and has been around since late 1989.
The distributors are at the mercy of Kodiak in the Bahamas and they are at the mercy of Rotax in Austria. The distributors here don't wield much power. They are more or less told how to do things or when they are going to get them. Stock is also controlled.



The AC pumps can be bad right out of the box or last 1000 hrs. Usually they just leak, complete failure are not near as frequent. You just never know. If you have a good working pump leave it alone. The new pumps will most likely hit the market in June.

[drseti]

The Pierburg pump which looks like the AC pump has worked well,

I replaced my AC with a Pierburg a few hundred hours ago, and so far no problems. In fact, I had no problems with the AC either; had to replace it to comply with a mandatory service bulletin.

Roger, thanks for keeping us all up to speed on Rotax issues!

[Jack Tyler]

Roger, thanks for responding. You seem to be touching on a critical issue (re: Rotax's reputation) when you stated:
"The distributors are at the mercy of Kodiak in the Bahamas and they are at the mercy of Rotax in Austria."

For what are the USA Rotax distributors dependent on a Bay St. business in downtown Nassau? (If anything at all, that explains a lot...). Could you explain this a bit further.

Perhaps my expectations are somewhat unrealistic; I'm picturing a well established Western European manufacturer with modern European quality standards. Yet the frustrations I hear others express do seem to be well summarized by some of what you said:

"Regardless of what people think, Rotax usually stays on top of things."
"The AC pumps can be bad right out of the box or last 1000 hrs."
"Rotax has been having issues with these pumps since changing mfgrs back in 2006."

Obviously, the first statement is inconsistent with either the second or third statement...yet the three seem to coexist in the marketplace in some kind of dysfunctional combination. Very puzzling...

Paul, what you describe re: use of an electric (supplemental or back-up) fuel pump is of course very much a norm - in fact, in each of the a/c I've flown. But there may be more to that particular story. E.g. there are a number of RV-12 owners who have experienced a momentary drop in engine performance, it's believed due to the onboard Rotax fuel pump, and the RV-12's electric pump is wired up to always be on, never off. IOW under some flight conditions - and it's easy to imagine one of them would be a takeoff - an electric fuel pump might not fully replace the engine driven pump's performance. This appears to be validated when looking at some of the Dynon data downloads, after the events.

But that's nibbling at the edges. The main point is that an engine driven fuel pump *should* be highly reliable on an aircraft engine. And I think that's been true for the American, certified engines. It's puzzling why it's been such a chronic issue on the Rotax engines.

[roger lee]

Hi Jack,

Rotax is a good dependable company. Could any company do better, well sure. Some of this slow communication that goes on is from being international and because of it's very nature needs lots of testing. Engines and parts have to go through a lot to get here to the US dealers not to mention a lot of handling. If Rotax was unreliable it wouldn't be changing pumps right now (on their own), but selling you more not so good pumps and just taking your money. Even with the testing things can be off when done in mass. Rotax realized this with the AC pump before too long and began looking for a better pump. many pumps were just fine, but yes there have been some issues too. This is no different from Ford, Chevy or any engine company. We out in the field don't get all the info, feed back from the field is not always speedy, finding a new substitute and then testing that can take months to years. Rotax actually does a good job as far as trying to make sure everything works as it is supposed to work, but the parts are made by people who don't always live up to our field expectations.
You should worry about a company that denies any problems unless forced to change through the cost of lives. Rotax is typically proactive, it just takes time.

[drseti]

Roger, do you happen to know what (if anything) is different about the new oil filter, other than that extra 3 mm of height? Clearance is an issue in my installation, and unless there's a definite advantage to the new filter, I'd just as soon have the tiny bit of extra room. (That is, assuming that the old filter is still going to be available.)

[roger lee]

The old filter will be gone when the stock is gone. You should not have a problem with the new filter fitting if the old one was okay. Many engines are tight between the exhaust and the filter during the installation of a new filter, but the new extra length is so small it should not be an issue. Not only do they have a different part number, but the box is all white verses the old blue/white.



Dec/10
Rotax Oil Filters changing, new part number assigned
by XatorMan under ROTAX PRESS RELEASES
Rotax; BRP-Powertrain, is making a minor change on the oil filter for ROTAX 912 and 914 Series engines.

Production of the current oil filters part no. 825704 and 825706 has been discontinued, once stock is depleted they will be not longer available.

The replacement filters will have a new part no. 825710 and 825712, internally they are the same and they have been approved from engineering, however one small change has to be noted. The overall length has increased about 3.5 mm ( .138″ ) due to the production process. For detailed dimensions see attached sketch.

OEM and end use customers need to check and make sure they have clearance and make any necessary changes to accommodate this new filter. The part will be coming in the first quarter of 2011.