912 let me down, again...

[sdemeyer]

Was out enjoying the nice PNW weather yesterday and my 912 started running like crap, again. Lately, this seems to be the case more often than not. Further investigation revealed a broken carb boot. I just replaced these six months ago to the tune of $100.00 ea. Lucky for me the carbs have retainer springs or the whole $#^&^ carb would have fallen off.

I'm becoming less and less impressed with Rotax and am seriously considering replacing with something a little more reliable, like a VW or even the Boxer motor off my BMW motorcycle.

I rarely see any Internet posts about problems with Rotax 912. Am I the only person alive with 912 issues, Sheesh?

[cap01]

scott , sorry to hear about the engine problem . awhile back there was a post on here about a place in ohio that makes and sells the rotax cab sockets . supposed to be some super rubber that makes them better than rotax . i think they were around 60 bucks , if you want ill email the address .
cliff at flying b

[SkyPirate]

If I ever use a 912 ,.that is one part I will re make out of aluminum or 308 stainless ,..seems allot have the same problem,..find a shop that has a mandrel bender and get a 10 inch piece of tubing the same size at the outlet ..ID measurement being the crucial,.have them bend up a tight 90 degree bend then cut the 2 radius sections out on each end where the bend starts and weld them to a flange that will fit properly ..use a straight hose that is fuel compliant from the new piece to the carb tube,..shouldn't have that problem again.

if you can not find a shop that has a mandrel bender ,.. propane fired roof furnaces have 308 stainless or inkanel tubes in them with a series of 90 degree bends in them,..a scrap yard might possibly have one or 2 kicking around ..cut a section of the tubing out that fits your need.

inkanel can be welded with stainless or nickel rod or wire,..best with tig.

Chase

[sdemeyer]

Do you have the 7 mm spacer on the hose clamp?
To me that looks like it has been tightened to hard on the clamp.

W

Well, I don't know what length the spacer is but it's the one that came with the new $100.00 sockets. Looks overtightned but I don't know how that could be the case, with the spacer installed.

[sdemeyer]

If I ever use a 912 ,.that is one part I will re make out of aluminum or 308 stainless ,..seems allot have the same problem,..find a shop that has a mandrel bender and get a 10 inch piece of tubing the same size at the outlet ..ID measurement being the crucial,.have them bend up a tight 90 degree bend then cut the 2 radius sections out on each end where the bend starts and weld them to a flange that will fit properly ..use a straight hose that is fuel compliant from the new piece to the carb tube,..shouldn't have that problem again.

if you can not find a shop that has a mandrel bender ,.. propane fired roof furnaces have 308 stainless or inkanel tubes in them with a series of 90 degree bends in them,..a scrap yard might possibly have one or 2 kicking around ..cut a section of the tubing out that fits your need.

inkanel can be welded with stainless or nickel rod or wire,..best with tig.

Chase

I'm guessing the reason for the rubber sockets is to absorb minor engine vibrations. I'm not sure how the carbs would hold up if they were solidy mounted. But, what do I know.... I'm the one with the broken engine

[sdemeyer]

scott , sorry to hear about the engine problem . awhile back there was a post on here about a place in ohio that makes and sells the rotax cab sockets . supposed to be some super rubber that makes them better than rotax . i think they were around 60 bucks , if you want ill email the address .
cliff at flying b

Thanks, Chuck. When I purchased the new sockets, to make a long story short, I ended up purchasing three. I was going to send the unused one back but I never got around to it. Thankfully I kept it so I'm back in business. However, due to the number of issues I’ve had, my confidence in the motor is deteriorating rapidly. I’m near the point where flying the KF is no longer fun and exciting. I went to Pt Townsend for lunch yesterday and I couldn’t help but notice the lack of emergency landing sites between here and there.

[SkyPirate]

sdemeyer,..
if your connecting a rubber hose to this flange,..the rubber hose is what is suppose to take out the vibration,..I'm sure that the reason for the plastic goose neck or flange is cost of manufacturing ,..it's allot cheaper to inject a one time made casting/mold for every flange made then it is to farm out the job to a shop that makes each piece individually.
I owned 2 of the shop's that did that type work,..plastics and injection molding pretty much took that type of production application away from the job shops,..with exception to fuel blocks ,..I did allot of filling for pre machined teledyne aluminum pump and valve castings,.
with some applications ,..plastics just don't cut it ,..luckily

have you got the 582 set up? if you do then the connection is pretty short between carb and flange,..you can move the carb out a little with a hose between carb and flange ,..it would if nothing else give a little more performance to your engine sort of like a tunnel ram,..


Chase

[sdemeyer]

sdemeyer,..
if your connecting a rubber hose to this flange,..the rubber hose is what is suppose to take out the vibration,..I'm sure that the reason for the plastic goose neck or flange is cost of manufacturing ,..it's allot cheaper to inject a one time made casting/mold for every flange made then it is to farm out the job to a shop that makes each piece individually.
I owned 2 of the shop's that did that type work,..plastics and injection molding pretty much took that type of production application away from the job shops,..with exception to fuel blocks ,..I did allot of filling for pre machined teledyne aluminum pump and valve castings,.
with some applications ,..plastics just don't cut it ,..luckily


Chase

Chase, I just went back and reread your original post. I missed the part about connecting the rubber hose from the new flange to the carb. If I have this problem again, I will definitely explore your idea as it sounds pretty good.

Thanks,
Scott

[SkyPirate]

if you want even more HP for the buck ..inside of the flange put 3 vorticy generators set at about 30 degree's,..just little fins about 3/8" tall that enhance the air as it is drawn into the engine,.. like a tornado so to speak,..more evenly distributed fuel to air mixture ,..almost all carburated auto engines have this either incorperated into the ventury or in a plate between carb and intake manifold ,..some after market intake manifolds use this as well pre built into it.

Chase

[Mnflyer]

Hi Scott, there were a bunch of crap Rotax/Bing carb sockets made a few years ago that cracked even the HKS engine experienced them cracking I had to replace both of my original sockets in less than 150 hrs of operation. I replaced them with the sockets from JBM products and so far no cracks. If the carb or airfilter rubs / contacts anything it will also cause them to crack much sooner, I can't say enough good about the JBM sockets and I know of other guys with the HKS engines that had the same problems and his cured the problem. heres a link to his carb socket page.
http://jbmindustries.com/ROTAX.htm