----[Please read http://ercoupers.com/disclaimer.htm before following any advice in this forum.]----
Chuck, As you're doing the Stromberg mixture installation, please contemplate this: I couldn't tell beans about good mixture control based on sound. Eventually, I could tell I'd leaned too much (by sound) when it sounded rough and rpms dropped off. That's gross and crude and I wouldn't want to trust my engine detonation protection to sound. (What is it? $12,000 for a major overhaul these days?) I had ridden in planes with non-high-resolution EGTs, the kind that show temps over a huge range on a single 2" sweep of the needle such as 500° (Alcor) or 800-1700° (Micro 100). Even though there're marks every 25° or so, they're so close together, it's hard to see and control the mixture with such a gauge. I had also ridden in planes with HIGH-resolution EGTs, the kind that show temps with nearly 1/4" per 25°. With this kind of gauge, you have to adjust the scale of the needle to keep the needle in the sweep area. Though you don't know what the absolute temperature is, you have VERY good control of CHANGES in the EGT. In those, we could accurately identify the peak EGT and easily peg 50° rich of peak for cruise or 100° rich of peak for high power for takeoff or climb. When I found I couldn't control the EGT by sound, I got a HIGH-resolution EGT from K&S and was very happy. Just now, looking at http://www.aircraftspruce.com, I don't see the high-resolution adjustable type gauges. I bet one of the digital gauges would give you the accuracy you need, such as the 1° resolution Sigtronics Digital EGT $165.50. If you can afford a 4-probe digital, that might be good. If you get a non-TSOed gauge, you'll have to apply for a one-time STC but it was a slam-dunk when I did mine. As always, talk to the FSDO BEFORE you buy the gauge and install it. My advice is: Don't start using any mixture control on you Coupe until you have a high-resolution EGT. These are just my opinions based on being a pilot-user. I'm nobody's kind of mechanic. Ed Burkhead http://edburkhead.com/ [EMAIL PROTECTED] (remove the QQQ) -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Sent: Friday, February 13, 2004 5:39 PM To: Ed Burkhead Subject: RE: [COUPERS-TECH] C85, Stromberg, Lean Idle problem Thanks, Ed: I originally purchased N3773H with a Stromberg that had its mixture apparatus removed. Recently I found a Stromberg in great shape with all fixtures (even the original mixture control cable. Larry Kruljac is installing it now... hope to fly with the eagles this summer (in the early morning of course!). Thanks again, Chuck Quoting Ed Burkhead <[EMAIL PROTECTED]>: > ----[Please read http://ercoupers.com/disclaimer.htm before following any > advice in this forum.]---- > > > > Chuck wrote: > > I am under the impression (perhaps in error) that the Stromberg > > carb must be 'wired' in the full rich position by "AD". > > Chuck > > Naw, that's B.S. that floats up around the airport from time to time, > spouted by the ignorant. No such thing came up on the AD searches by > any of the SEVERAL GOOD mechanics I used over the years. > > Stomberg's lean just fine. As I mentioned, the response seemed much > slower to me than the leaning in other carbs. Make small, slow > adjustments and watch your high accuracy EGT and you'll see that you can > easily control it to any 10° spot you want. I could easily set it to > 50° rich of peak for cruise and 100° rich of peak for max high-altitude > power. > > > High, thin-air cruising isn't for everyone. I suppose, for anyone out > West, it's a regular part of flying. > > With leaning, you can more easily go high for long-distance cruises and > make your Coupe a MUCH better traveling machine. I could, for example, > plan to fly high, slow down to 75 indicated (93 true), leaned, at 3.5 > gph. That would give me fuel burn of one hour to climb at 5.5 gph, and > 31/2 hours at 93 mph. That's 4.5 hours averaging around 90 mph for 405 > miles with a 6 gal. reserve. It IS NECESSARY to avoid drinking liquids > before takeoff, through the flight till starting the letdown to > comfortably manage this range. > > When you figure that a fuel stop takes about an hour to fly the pattern, > land, taxi, de-water, fill the tanks, pay, take-off and get on course, > any fuel stop you can avoid is a BIG increase in your average cruise > speed. Sometimes, depending on prevailing winds, weather and trip > length, it's worth doing. > > By the way, the air up high is almost ALWAYS as smooth as glass. > > Ed Burkhead > http://edburkhead.com/ > [EMAIL PROTECTED] (remove the QQQ) > > -----Original Message----- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] > Sent: Wednesday, February 11, 2004 11:25 AM > To: Ed Burkhead > Cc: roger anderson; Coupe-Tech > Subject: RE: [COUPERS-TECH] C85, Stromberg, Lean Idle problem > > I am under the impression (perhaps in error) that the Stromberg carb > must be > 'wired' in the full rich position by "AD". Can you correct me on this? > My > home airport is Sunriver, OR @ 4158 AGL! > > Chuck Rosenfeld > N3773H > > > Quoting Ed Burkhead <[EMAIL PROTECTED]>: > > > ----[Please read http://ercoupers.com/disclaimer.htm before following > any > > advice in this forum.]---- > > > > > > > > Roger, > > > > I had a similar rough engine in flight after I descended from 10,500' > > one day to 2,000.' Pulling the carb heat made it run smoother and > full > > power was also smoother than lower power. It seemed like the engine > was > > running excessively lean. I was worried about detonation damage. > > However, I was only 5 miles from the airport by this time so I > continued > > to the airport with carb heat on. > > > > My favorite mechanic was at the destination airport so he pulled the > > carb. He found the internal tube from the venture to the mixture > > control system had become plugged with fibers from the recently > cleaned > > air filter. (I never used the fiber-based air filters again!) > > > > We cleaned the carb tubes, cleaned the mixture control assembly, > > stropped the moving plate against the non-moving plate, re-cleaned it > > all, assembled the carb, removed the wired-full-rich safety wire and > > tested operation of the push-pull control. > > > > >From then on, I was able to lean my engine and get great long-range > and > > low fuel burn on cross-country trips when I wanted to. It probably > > helped my high-altitude operation when I flew out west a few years > > later. Be aware that the Stromburg carb leans just fine but you have > to > > move the control slowly and watch the sensitive EGT. *I* think that > the > > Stromburg mixture changes somewhat slowly, NOT instantly, but it does > > work accurately and reliably. > > > > I did find that I could not personally hear the engine roughness with > > adequate reliability on the C-85 in my Coupe. I got a high accuracy > K&S > > EGT and was happy forevermore. > > > > If you haven't done so, you might want to have those internal tubes > > checked in the carb. It took about 2 to 21/2 hours of labor for all > this > > on my plane. > > > > Ed Burkhead > > http://edburkhead.com/ > > [EMAIL PROTECTED] (remove the QQQ) > > > > -----Original Message----- > > From: roger anderson [mailto:[EMAIL PROTECTED] > > Sent: Monday, February 09, 2004 9:10 PM > > To: [email protected]; [EMAIL PROTECTED] > > Subject: [COUPERS-TECH] C85, Stromberg, Lean Idle problem > > > > > > ----[Please read http://ercoupers.com/disclaimer.htm before following > > any advice in this forum.]---- > > > > > > A C85 and a Stromberg. At idle and lower rpms, very rough, won't take > > throttle, coughs, backfires. However, pull out carb heat and runs > good. > > Mag check at 1700 rpm will frequently be rough, large drop, misfiring. > > Pull out carb heat, smooth. Runs good at higher rpms. Have pulled > carb > > off, checked mixture housing, cleaned plates under, wired full rich > now. > > Float level correct. Cleaned and blew out everything. Checked all > > hoses, clamps, etc for vacuum leak. Everything tight. Idle mixture > > screw out to almost 3 turns now. By the carb heat correcting the > issue, > > it sure indicates a lean mixture idle circuit problem. Any thoughts > or > > other suggestions? Thanks ...Roger > > > > > ======================================================================== > > ====== > > To leave this forum go to: http://ercoupers.com/lists.htm > > Search the archives on http://escribe.com/aviation/coupers-tech/ > > > > > > > > > > > ======================================================================== > ====== > > To leave this forum go to: http://ercoupers.com/lists.htm > > Search the archives on http://escribe.com/aviation/coupers-tech/ > > > > > > > > > > ======================================================================== ====== > To leave this forum go to: http://ercoupers.com/lists.htm > Search the archives on http://escribe.com/aviation/coupers-tech/ > > > > ========================================================================== ==== To leave this forum go to: http://ercoupers.com/lists.htm Search the archives on http://escribe.com/aviation/coupers-tech/
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