Replies to This Discussion

Permalink Reply by Don Burkholder on May 19, 2019 at 2:57pm

I actually like the Bing, once I understood the different systems and how they are supposed to work. The sensing port was very rough inside and once cleaned and smoothed out made an improvement, as it gave more air energy to the atomizer to shear fuel. This is why it is very critical to make sure there is nothing remotely in front of this port entry, located at the 6 o'clock position of the carb air entry. Even an air elbow that is too close to the entry can influence this port..

DonB

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Permalink Reply by George Snedeker on May 19, 2019 at 4:53pm

i will look for that...I plan on getting a rebuild kit and installing it

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Permalink Reply by Jan Eggenfellner on June 1, 2019 at 10:57pm

Inflight shutdowns should NOT be the norm.  

Once you accept it as the norm, you are the test pilot of a poor design.  

Now, be 100% sure your throttle cable support bracket is 100% attached to the engine, and not to the firewall.  If it is attached to the firewall, the thing will shut down at every landing

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Permalink Reply by George Snedeker on June 2, 2019 at 8:15am

thanks jan...will check it

Permalink Reply by Thomas Norris on October 17, 2019 at 7:06pm

I realize that I'm late to this discussion, but I didn't start phase 1 until mid July.  I've built a 750 Cruzer with a new 4th generation Jabiru 3300 with a Bing carb and the dual throttle set up using a Whirlwind ground adjustable prop set at 15 degrees.  I have not had problems with the engine stalling when I pull the throttle back.  My problem is with the response curve when I push the throttle in.  As I push the throttle forward, the rpm's increase steadily to about 2700-2800, and the fuel flow increases steadily (The engine does seem to run a little rough at that point, and smooths if I back off a bit on the throttle).  This increase in rpm and fuel flow occurs smoothly up to the point the throttle is about 1/2 to 2/3 advanced.  Beyond that point, the rpm's begin to drop and the fuel flow increases.  Suggestions?  Is there a top end stop that needs adjusting?

I am also wondering if there is a better throttle control for dual throttles mounted laterally on the panel than the solid rods sticking through the panel that come with the Zenith/Jabiru FWF kit.  I would really like to have friction locks and vernier controls on the throttles.  I saw the lever type that aero conversion offers.  Is anyone aware of other alternatives?

Thanks

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Permalink Reply by John Austin on October 17, 2019 at 8:52pm

McFarlane makes a "Vernier Assist" throttle - it's a push-pull throttle with a friction lock - you can leave it in any position and then twist the vernier knob to fine-tune the setting.  I have the "Vernier Assist" mixture control and am about to install the throttle, too, because I like it so much!

John

N750A

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Permalink Reply by John Austin on November 26, 2019 at 8:05am

I just installed my Vernier-Assist throttle the other day and flew it.  I really like the ergonomics - when you lay your hand on throttle knob, the fingers naturally fall on the knurled friction adjustment knob.  You can push-pull the throttle to get an approximate setting, then fine-tune the rpm's with the vernier assist by twisting the knob.  Supposedly this is a "jam-proof" design as opposed to other vernier throttles - works great!

John

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Permalink Reply by Thomas Norris on January 3, 2020 at 6:55pm

John: Thanks for the suggestion.  I ordered McFarlane's vernier assist custom cable for the pilot's side and installed it--works great--much better control than the old rigid rod.  I also ordered McFarlane's friction lock, without the "guts" , for the co-pilot side. 

I replaced the main jet that came with the carb (255), first with a 250 and then with a 245.  That has helped overall performance, but it still has a tendency to peak on RPM, and then fall off, just before wide open throttle.  Don Burkholder suggested checking the scat tubing into the carb, and that will be my next move.  Thanks, Tom

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Permalink Reply by Rich Astley on October 16, 2022 at 10:46pm

Any chance you can post the part numbers and/or links for the throttle cables you used please.

Cheers

Rich

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Permalink Reply by Thomas Norris on October 17, 2022 at 1:01pm

Rich:  I don't have the part numbers--sorry.  However, I have had another serious throttle issue, not involving the McFarlane controls.  During the late spring, my throttle froze--I couldn't move the throttle.  Fortunately this was discovered during preflight, and I found that the cable connecting the carb (not the McFarlane cables connecting the throttle knob to the dual throttle bar) to the dual throttle linkage had siezed.  I removed it and found that the sheath had melted.  I replaced it and the same thing happened.  I ordered another and talked with the US Jabiru experts who thought the battery ground to the engine was shorting through the throttle cable.  I followed their advice and installed a new, oversized battery to engine block ground cable.  I installed the new throttle cable and it seemed to work fine.  On July 4, I planned to taxi the plane to the fuel pump for a flight on July 5.  I pulled it out of the hangar and got in.  When I started it, the engine was at wide open throttle (WOT).  Pulling or pushing the throttle cable had no effect on the engine, and the brakes were not holding the plane at WOT.  I steered as best I could, while trying to shut the engine down and turn off the fuel.  About 150 feet down the taxiway, the plane hit an illegally parked car.  I was taken to the hospital by ambulance, having sustained a large head laceration and a concussion.  Both the plane and the car were totaled.  I do not know the cause of the throttle malfunction, but I suspect that the cable to the Bing carb was at fault.  No one else was hurt, and I consider myself lucky not to have been injured more seriously.  Clearly, careful attention needs to be paid to throttle cable issues.

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Permalink Reply by Rich Astley on October 18, 2022 at 4:32pm

Oh my gosh Thomas,  Im very sorry you had to go through that experience but am happy that you are ok and no one else was hurt.

I'll take a close look at my throttle system and examine it in detail.

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Permalink Reply by Don Burkholder on December 21, 2019 at 7:23am

Hi Thomas.  Did you try backing off the 15 degree prop setting slightly? Just small fractional increments to reduce the load? Other than this, what size main jet do you have? Do you experience uneven exhaust temps at full throttle? The bottom of the Bing air horn has a large port that must not have anything near it as this provides a pressure differential across the atomizer and fuel needle port. 

  3300's extra length and tighter firewall clearance shortens the distance the air has to become laminar before reaching the air horn. My shorter 2200 had an elbow that allowed a 4 to 5 inch straight leg to the entry of the carburetor. Example? Scat hose has been known to "bunch up" near the air horn causing issues.. My previous posts involved my Bing modifications and may be of interest.

Hope this helps..

Merry Ho Ho

Don

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