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MANDATORY ROTAX? Alert SB

I was on the fence ordering my Sling 2, as to which engine I wanted. TAF convinced me that maybe I’d want the 912 ULS, at the time, rather than the iS. All due to the VIRB ration issues the iS was still exhibiting. So far, I’ve only had one recent SB, for carb circlip replacement, less than an hour job. On the other hand, the iS motors have had several SB,s, especially the 915i#.
 
Engine Serial Number

At least based on the engine serial numbers affected, I'm in the clear. My mechanic will check the part serial numbers anyway. Anything labelled "before next flight" gets my attention real quick.
 
You may want to take another look. I don't see any engine serial numbers listed.
 
Just as a point of reference, I received my Powerplant kit May 20 this year. My pump assembly SN is 18.0708, which is within the potentially impacted range.
 
Fuel pump serial number availability

One problem I see in checking the serial numbe for the fuel pump assembly it?s that, per the KAI, the first thing to do is remove the cover on the fuel pump assembly, and not put it back on. We most likely disposed of this in-needed cover, so, unless we have the serial number on our documentation, we may be up that well-known polluted tributary without a means of propulsion. It appears the two actual fuel pumps do have serial number, which we could read?but we need to know what fuel pum ranges have the bad innards.
 
Well, yah, but

The SB indicates the potentially impacted S/N ranges: 180500-192699.

This is the ASSEMBLY part number range. This is on the cover of the assembly, which cover was removed for the RV12iS implementation. There are serial numbers on each of the two FUEL PUMPS, which we should still be able to read?but the service bulletin says nothing about the serial number range of the bad individual fuel pumps.
 
Well, I think I?m crying wolf

Looking at the fuel pump picture, the Assembly S/N is NOT on the cover we threw away?its on the base that the cover covers, so I should be able to see the serial number.
 
When you get the chance to look at the pumps you?ll see both the main and aux pumps carry the same part and S/N as the assembly, leading me to believe the entire assembly is the only way one can get them. I?d be happy if someone could prove that assumption wrong as it will be a more economical solution.
 
Hope this photo helps a bit for builders that are not sure where the S/N are and what they look like. These are mine before install. Lucky for me my S/N are not in the I'm screwed range.

oFU.jpg
 
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I was on the fence ordering my Sling 2, as to which engine I wanted. TAF convinced me that maybe I?d want the 912 ULS, at the time, rather than the iS. All due to the VIRB ration issues the iS was still exhibiting. So far, I?ve only had one recent SB, for carb circlip replacement, less than an hour job. On the other hand, the iS motors have had several SB,s, especially the 915i#.[/QUOTEt]ake the

Hey John, did you remove the carb to replace the circlip?? I was just looking at my engine and it looks like it would be an easy job if you could just take off the chamber top to access the needle to replace the clip, instead of having to remove the carbs first. Or, am I missing something.

Thanks..............Tom
 
I was on the fence ordering my Sling 2, as to which engine I wanted. TAF convinced me that maybe I?d want the 912 ULS, at the time, rather than the iS. All due to the VIRB ration issues the iS was still exhibiting. So far, I?ve only had one recent SB, for carb circlip replacement, less than an hour job. On the other hand, the iS motors have had several SB,s, especially the 915i#.[/QUOTEt]ake the

Hey John, did you remove the carb to replace the circlip?? I was just looking at my engine and it looks like it would be an easy job if you could just take off the chamber top to access the needle to replace the clip, instead of having to remove the carbs first. Or, am I missing something.

Thanks..............Tom

Neither carb must be removed from the engine for circlip replacement. Simply remove top cap and slide. Use high-grade slotted screw driver that fits central screw retainer. If thread Loctite doesn't loosen use heat iron on top of screw. Heat loosens Loctite...
 
I was on the fence ordering my Sling 2, as to which engine I wanted. TAF convinced me that maybe I?d want the 912 ULS, at the time, rather than the iS. All due to the VIRB ration issues the iS was still exhibiting. So far, I?ve only had one recent SB, for carb circlip replacement, less than an hour job. On the other hand, the iS motors have had several SB,s, especially the 915i#.[/QUOTEt]ake the

Hey John, did you remove the carb to replace the circlip?? I was just looking at my engine and it looks like it would be an easy job if you could just take off the chamber top to access the needle to replace the clip, instead of having to remove the carbs first. Or, am I missing something.

Thanks..............Tom

Hi Tom, no removal, just what a piper J3 said. I had Midwest Sky Sports do mine. We found both original CirClips loose, one worse than the other. No carb sync either.
 
I had Midwest Sky Sports do mine. We found both original CirClips loose, one worse than the other. No carb sync either.

The circlip is not really loose ? it is pinched by the screw in the slide from above. The main needle is designed to float which gives the appearance that the circlip is loose. The needle needs to float so it centers itself in the main jet and doesn?t rub on the jet which would cause wear and allow a rich mixture. It?s interesting? the needle centers itself with the ~5 GPH flow of gasoline coming vertically up thru the main jet.
 
The circlip is not really loose ? it is pinched by the screw in the slide from above. The main needle is designed to float which gives the appearance that the circlip is loose. The needle needs to float so it centers itself in the main jet and doesn?t rub on the jet which would cause wear and allow a rich mixture. It?s interesting? the needle centers itself with the ~5 GPH flow of gasoline coming vertically up thru the main jet.

Trust me, they were loose. MWSS is very familiar with ROTAX engines. When we removed the needle we found one clip to be way too loose. This on a relatively new engine, just under 100 hours. The reason for the SB, saw clips fail, and foul the carbs. The replacements were sturdier (Originals Mfgr?d too soft) and you could see the new ones fit snugger than the originals. They still had play, but weren?t wobbling on the needle, as were the originals.
 
expensiv and a lot of work

Hello,
I like the idea of an injected engine in my RV, but my RV-12is will get a 912ULS engine after much consideration and asking friends. Reasons for this were the high number of SB's for the iS engine, the price tag and this funny fuel pump assembly behind the bulkhead. Can someone tell me how it is possible to change the fuel pumps without cutting off the empennage?
 
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I’ve already done so for the fuel pump SB. Wasn’t as bad as I expected. Loosen two AN fittings, which are accessible from the opening in the baggage compartment bulkhead and remove the six screws for the fuel pump assembly tray accessible from inside the baggage compartment, disconnect the fuel pump electrical connectors and fuel pressure sensor connection and the assembly drops out.

Replacing the assembly wasn’t that tough either. You do have to remove the seat back and lay over the fuel tank to reach in there though.
 
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