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New member of the 'Sinker Club' (carb floats)

I don't think he means 100 hour oil changes, but rather an analysis every other oil change (assuming 50 hour changes).
 
No, I mean I'm changing the oil every 100 hours (or 12 months) with Aeroshell Sport Plus 4, per the Rotax maintenance manuals. And every time I change oil, I'm sending a sample to Blackstone for analysis.
 
Dale,

What?s your engine total time? If it?s less than 500 I can see how you could go 100 hrs on an oil change, but after that my oil was pretty brown at 50 hr intervals.

Rich
 
Dale,

What?s your engine total time? If it?s less than 500 I can see how you could go 100 hrs on an oil change, but after that my oil was pretty brown at 50 hr intervals.

Rich
480-something right now. Like I said, we send a sample off to Blackstone every time, and what I really like is the comparison with previous reports.

Actually, looking at the last report -- I forgot that we only went 50 hours on that one, because we did the CI early to avoid taking the plane out of service during the best flying weather. The numbers on the elements in the oil were very close... the only big difference was iron (up 50% for double the hours), calcium (up 11%), zinc up 8%. Viscosity, flashpoint, etc. all were well within normal range.

We'll continue to change annually or at 100 hours, and have the oil analysis done each time. I'm sure the engine will make it to or beyond TBO... not so sure about the pilots, though.
 
We might or might not be members of sinker club at 190 hrs. Plane is exhibiting smell of fuel in cockpit, twice in mid flight.

Became noticeable after we got up in elevation, temps got cooler, and we closed the side vents.

As long as it was warm on the ground, the vents stayed open until about 5500 AGL where it was cool enough to need to shut the vents, and then the odor became apparent. This is in November in So CA.

An inspection is in order. Not smelling fuel when we open the oil check port after flying coming from the engine area, so line of thought is that it's somewhere from the fuel filler port to fuel tank, to red box, electric fuel pump and the mechanical fuel pump, but all areas need to be checked and inspected for signs of blue stain from 100 LL fuel.
 
Fellas, What am I missing? Some of us determine to spend a heap of dough on an airplane, risk life and limb to enjoy it, and then seaming become tight on oil. Why risk all that by hedging against max oil life, other than because you can. IMHO, I share a belief amongst other equipment operators: Oil is cheap and the fresher it is, the happier our work-horse engines are. Please clue me in on the logic of changing oil at the absolute latest possible time?
 
Fellas, What am I missing? Some of us determine to spend a heap of dough on an airplane, risk life and limb to enjoy it, and then seaming become tight on oil. Why risk all that by hedging against max oil life, other than because you can. IMHO, I share a belief amongst other equipment operators: Oil is cheap and the fresher it is, the happier our work-horse engines are. Please clue me in on the logic of changing oil at the absolute latest possible time?

Very simple... 100 hours is Rotax recommended oil change interval if using 100% synthetic oil and unleaded Mogas. Just like an automobile - you don't change oil at 2500 miles if manufacturer specifies 5000 mile interval. The car I now drive specs 10,000 mile oil change. Modern engines (Rotax) with close mfgr tolerances, good metallurgy, and water cooling far surpass the 1940's technology still used by Continental and Lycoming.
 
Very simple... 100 hours is Rotax recommended oil change interval if using 100% synthetic oil and unleaded Mogas. Just like an automobile - you don't change oil at 2500 miles if manufacturer specifies 5000 mile interval. The car I now drive specs 10,000 mile oil change. Modern engines (Rotax) with close mfgr tolerances, good metallurgy, and water cooling far surpass the 1940's technology still used by Continental and Lycoming.

I feel the same way, and to make sure I'm not doing it wrong I've been using Blackstone oil analysis to verify the oil condition. That said... there will always be people who change the full synthetic oil in their cars every 3,000 miles even when the manufacturer says 10,000. Oil change shops have done a wonderful job of convincing people that it's a good idea "just to be safe", despite the tremendous waste of oil.
 
Follow-up to post #132 above...

So, I spent $345 plus shipping for two sets of 861-189 floats and two gaskets. I did the installation this morning and took my digital gram scale with me to measure the old floats, and you guessed it, each pair of floats weighed less than 7 grams. Original floats with 428TT and 100% 93E10. Nuts...

Friend Bob just went through the same thing... Smell of fuel was coming from a non sealing O-Ring on the gas cap, despite the latch and bolts tensioning and compressing/displacing the o ring slightly in the filler neck tube. Replaced the O-Ring, Bob thinks it might be an annual replacement job, adjusted the "squish" of the O-Ring, and the smell of raw fuel is now gone from the cockpit.

It will now take a flat blade screwdriver to move/pry the latch up to remove the fuel cap, from here on out.

Hope this helps someone else.
 
heavy floats

This is 2019 isn't it? I started working in my dad's service station 50+years ago. Rebuilt a multitude of carbs and I don't remember sinking floats. In 50+years Bing carbs have gone backwards. This is my 4th set if bad floats in 3 years. That's $600+ in new floats. Come on Rotax! Sorry for the rant.:mad:
 
This is 2019 isn't it? I started working in my dad's service station 50+years ago. Rebuilt a multitude of carbs and I don't remember sinking floats. In 50+years Bing carbs have gone backwards. This is my 4th set if bad floats in 3 years. That's $600+ in new floats. Come on Rotax! Sorry for the rant.:mad:

I'm curious if your latest failed floats are the newest PN 861 189 with shortened brass guide sleeve? I don't know of any 861 189 floats that have failed.
 
Yes they are the new floats

That's unfortunate. I haven't heard of the new floats failing. A lot of us bought the new floats thinking the shortened brass sleeve would decrease overall weight and add buoyancy. Oh, well...

When your floats sank did you weight them?
 
I think my last sinkers were the new ones with the short sleeves ... Mogas with ethanol used exclusively.
 
I replaced my good working floats with the new ones (with the shorter brass sleeve) when they were first made available in the hopes I could forget about checking the floats regularly and only do it on condition inspections ... figured I could use the old ones as tool kit spares.

Hearing one of the new style floats has failed already is indeed sad news.

For the life of me I can't understand why Rotax does not make the carb floats using a material other than a fuel adsorbing foam. If they end up being a little heaver, so be it, change the manual's weight specifications and adjust the fuel float level accordingly and put this PITA issue in the rear view mirror.
 
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Question

I?m at 380hrs on my original floats and in 2016 at had an issue while getting ready to depart Oshkosh. I thought it was a float issue so since Lockwood was right there I walked to their booth and bought two pair of 186-184 floats.

I got the fuel leaking issue resolved, float gasket problem, and didn?t use those newly purchased 186-184 floats keeping them as spares.

My question is as I backed through this thread it appears floats 186-188 & 189 with a red ?R? are the most current floats being sold by the various distributors? Are the 186-184 the problem floats? Can I even rely on these to have any longevity?
Thanks
 
After some 14 months and 167 hours (Hobbs) using primarily Shell 91 mogas with <10% ethanol, my four #861188 floats (ROTAX says these floats are the same as the latest #861189 floats) now weigh 3.6 / 4.7 grams and 5.4 / 4.1 grams. ROTAX has not solved its float sinking problem.
 
After some 14 months and 167 hours (Hobbs) using primarily Shell 91 mogas with <10% ethanol, my four #861188 floats (ROTAX says these floats are the same as the latest #861189 floats) now weigh 3.6 / 4.7 grams and 5.4 / 4.1 grams. ROTAX has not solved its float sinking problem.

To be correct, Bing Carburetors has not solved the sinking float problems with their vendor or supplier. Try another brand of Mogas fuel, instead?
 
Out of frustration, I talked to the Bing US Distributor Tech Rep. Was told that Rotax does not buy their replacement floats from Bing. Sounds like they found a cheaper manufacturer. Was able to buy floats from Bing for $110 a pair. That's $40.95 cheaper than Lockwood. Additionally I talked to Jeff at Marvel Scherble (sp). He said that their manufacturer was doing a redesign on their floats and that he could not give me a date; however, he did say he would call me if he could get any more information.
 
Out of frustration, I talked to the Bing US Distributor Tech Rep. Was told that Rotax does not buy their replacement floats from Bing. Sounds like they found a cheaper manufacturer. Was able to buy floats from Bing for $110 a pair. That's $40.95 cheaper than Lockwood. Additionally I talked to Jeff at Marvel Scherble (sp). He said that their manufacturer was doing a redesign on their floats and that he could not give me a date; however, he did say he would call me if he could get any more information.

When you pull your new BING floats out of the box, take some pictures of them and post them up here. Maybe also post up the part # you ordered, too, or a link to order from Bing, so others might find a solution to this problem.

IMHO, asking Rotax to source out replacement floats for Bing Carburetors makes about as much sense as Van's sourcing out floats for Bing Carburetors on 912's. It's just not their speciality.
 
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Just another data point

Just another data point in this (hopefully ever ending) story. I replaced the floats of the right carb. on my first annual at TTAF 32h. Weight was exceeding the specs.
Engine has always run well. No issues. Hope the new pair will last a while now.
 
Sinker Update

I believe my floats are headed toward the ice burg. Are there any updates on the best current solution? OEM or aftermarket success?

Thanks,
Frank
 
Here we go again with usual questions?

? What floats do you have?
? Do you know PN?
? Do your floats have brass sleeve full height of float?
? Have you weighed your floats?
? What makes you think your floats are problematic?

So, latest float is PN 861 189 with shortened brass sleeve. I?m not aware if Marvel Schebler has re-introduced their epoxy floats.

Keep your old floats for emergency spare. The floats will dry out after several weeks and should again weigh less than 7 grams at that time. Keep spare floats in the plane along with tools to drop float bowl. I got stranded with overflowing carb and no spare floats. That won?t happen again?
 
New member of the 'Sinker Club"

I'm doing my condition inspection right now. When I weighed the floats yesterday, one side was over 7 grams and the other side was just under 7 grams. Both were higher than when I weighed them last year. So I ordered two sets today and will install them when they arrive next week.
 
Lucky aeroquip doesn?t have a problem making fittings that don?t dissolve in gasoline.
Unbelievable that it?s a problem to make a float that floats for airplanes.
 
My xperience with AVGAS and occasional Car Gas is no sinkers or weight changes in over 400 hours. How hard is it for the carb and engine mfg to rule on the effects of ethanol on floats.
 
My xperience with AVGAS and occasional Car Gas is no sinkers or weight changes in over 400 hours. How hard is it for the carb and engine mfg to rule on the effects of ethanol on floats.

I'm not sure ethanol is necessarily the issue. My understand is that BRP-Rotax tested their engines in Brazil where the fuel, I think, is as high as 25% without issue.
 
I'm not sure ethanol is necessarily the issue. My understand is that BRP-Rotax tested their engines in Brazil where the fuel, I think, is as high as 25% without issue.

Maybe they just tested engine performance as in the combustion cycle and not about effects on prolonged engine component exposure.
 
Marvel Schebler

Last year M/S told me they thought the "new" Rotax floats would be in inventory by late fall. Then it was before the end of the year, then it was sometime in January, and recently they said surely by the end of March. It's now March 31 and still no sign of new floats. I'm a patient guy but....

Rgds..........Ski
 
So I thought I finally joined the club. As I was bragging earlier in this thread about having my original floats with 1000 hours. and they weighted less that 6g per set. Well within spec. and working fine. The other day on a flight I felt a little shudder in the engine in cruise flight and the smell if fuel. OK I know what that is. I got it to do it again on the runway after landing. So I removed the floats and weighted them just like before they weight good on a calibrated reloading scale. 2 @ 3g and 2 @2.8g. So I checked float level it was in spec. I could not make them over flow with the electric pump on at 3 psi. So thought the mechanical fuel pump was having short burst of higher PSI than it should . I never caught that on the dynon. My fuel pump(newer style) had 700 hours on it so I replaced it. No good same symptom's.
Ok now I replaced the float valve and float bracket and the floats. Then set level to spec. I also replaced the diagram's all though to old ones looked good,

No good same symptom's.

This is a totally intermittent problem . The one constant is it happens after I have been flying for between 30 and 45 minutes No other time. After I get it back on the ground after this happens I can get it to really drop rpm and shake like **** with fuel smell and fuel on the drip pan.

So where do I go from here. I am beginning to think its not a carb problem at all. It seems to be heat related . It always starts and runs very smooth and the carbs are in perfect sync.

I am wondering if maybe an intermittent loss of ground on the ignition system after warming up?? This would might cause shaking and vibrating that makes to bowls overflow causing the fuel smell and bowl overflow.

So I saved my original floats with 1000 hours. I never replaced them for fear of getting bad ones like many others on this forum.

Any ideas guys.

Thanks
Brad Stiefvater
Salem SD
n124bj first customer built 12 to be airworthied and fly
maiden flight 9-20-2009
 
Cycle ignitions approx. 2 minutes after engine start with enrichener (choke) off. Do this at ~2500 RPM. Then check again at 4000 prior to flight with engine warmed up. Also check ignitions in-flight at cruise RPM. Then, when back on the ground, and engine running rough, check ignitions again at idle and at 2500 RPM. Report back findings?
 
Jim

Thanks for the reply
I cant do that its all I can do to keep it running when I can replicate it on the ground.

I little more info here. I was on a test flight yesterday and every thing was smooth and perfect. Then I notice a slight stumble didn't lose and rpms but I noticed the left EGT drop 150 degrees then recovered in seconds. So OK get back on the ground. So I tried to replicate the failure and I got it to fail again this time the right EGT dropped suddenly by 600 degrees. Flooding and shaking like **** . The fuel flow went to 10.5 GPM.

I have been doing mag checks through out all PRM ranges for the last three weeks of this search and all where perfect.
 
I'm re-reading your post #190... You installed new floats, or still running original floats with 1000TT?
 
Sounds like possible debris in fuel lines jamming the fuel shut off valve wide open, that the floats are trying to close down when the float bowl is full.

Check for debris in fuel tanks, lines, carbs, float bowls, to see if there are any partial obstructions.
 
Just spit-ball'n here... If you suspect the float is not shutting off the needle valve then perhaps remove the carbs and test on a bench. Not the easiest thing to do. You will need to make hose with banjo fitting to adapt to carb fuel inlet and then enough hose length to make column height for 5psig. It would be very tall column and not practical. So, use shorter hose and method to pressurize - perhaps a hand-bulb. Not best situation, and probably two-man operation, but it would tell you if float valve is not up to the task. You could run this experiment with float bowl on and with float bowl removed. With bowl removed, you can operate needle valve pivot by hand and observe.
 
Good Idea. Jim

Yesterday I did the the syringe testing method to see how much fuel it would take to make it run out the over flow tube. This method is explained in SB-912-065ul.

I found it only took 20 ML to overflow. So I set the flow level down and retested and got 30 ML. The Rotax SB says the correct range is 23 to 40 ML

Originally I set the float level to spec by measurement's only when I put new valve ,floats and bracket in. So my test yesterday showed the float level to high.

I will be doing some test running to see how that goes.

Thanks
 
Maybe being just a little past the acceptable level would explain the intermittent nature of the problem.
 
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