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#21
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A strange richness...
Lycoming IO-540C4B5 on the non-turbo models.
"john smith" wrote in message ... Are Aztec engines Continentals or Lycomings? Continentals sometimes have a fuel return line. I do not know if Lycomings do, also, but I have not seen one that does on any of the aircraft I have flown. |
#22
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A strange richness...
On 2006-04-26, Jay Honeck wrote:
I probably shouldn't have used the primer at all, but it was in that goofy, "in-between" length of time, where the engine wasn't really still "hot" -- but it wasn't really "cold" either. I've found on all the carburetted engines I've flown behind - priming is only needed if the engine is absolutely stone cold. Even if the plane has been just sitting in the sun and not flown in 3 days, the warmth of the sun is enough that priming isn't usually needed. -- Yes, the Reply-To email address is valid. Oolite-Linux: an Elite tribute: http://oolite-linux.berlios.de |
#23
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A strange richness...
I've got an IO-360 and I have always used the crank at lean procedure. In
fact, I crank at full lean until it fires. I don't open the mixture until I get some sort of bark from the engine. When hot, no priming. Works every time. I fly an amphib so being able to reliably start - even when hot - is very important to me since I could be drifting toward obstacles after pushing off from a dock. I tend to underprime. I would rather prime a little, try to start, prime a little more, start. I find this more reliable than overpriming and then trying to clear the engine. The only time I have not been able to start is when I primed a hot engine. -- ------------------------------- Travis Lake N3094P PWK "Jay Honeck" wrote in message oups.com... On our flight to Nevada, I was impressed with the smoothness and car-like predictability of Jim Burns' start-up technique with his Lycoming IO-540s. Jim had a way to start them that I'd not seen demonstrated before, which I will describe he 1. Fuel pump on 2. Electric primer on for (a few?) seconds 3. Crack throttle 4. With mixture at full lean, start cranking 5. Gradually enrichen the mixture until the engine fires (I may have some of this wrong, as the Aztec has nearly every switch and gauge in bizarre, usually invisible locations...) By using this method, his engines both started without cranking or coughing, just like my Subaru. So, of course, I've been experimenting with this method, which is quite different than the one described in my POH. (Which basically says "crank at full-rich"...) It has worked perfectly several times, especially on hot starts, until yesterday. Yesterday, after a short stop for a piece of pie ala mode at a nearby airport, I primed a few pumps, cracked the throttle, and started cranking with the mixture at full lean. I slowly enrichened the mixture until the engine caught...at which point it ran VERY rough, and did not want to stay running. This condition continued until I LEANED the mixture back, at which point everything returned to normal. I was able to slowly enrichen back to full rich, with no further difficulty. Mag checks were normal, and the flight home -- after a very careful and prolonged run up -- was normal. What happened here? Why did this technique induce an over-rich condition? Theories, anyone? -- Jay Honeck Iowa City, IA Pathfinder N56993 www.AlexisParkInn.com "Your Aviation Destination" |
#24
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A strange richness...
I also have an AEIO-540 in my Extra, and the starting procedure is:
Mixture full rich Throttle full forward Run electric boost pump for a few seconds Idle cut off Throttle cracked Crank Mixture forward Starts every time, hot or cold, and this is with a lightweight starter and pretty small battery. Sounds pretty similar. |
#25
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A strange richness...
O-320 in a 172M
When cold using closed throttle - Minimum prime (maybe 1), check compression of all 4 cyls, roll the airplane out, then 1/2 shot on initiation of cranking. When warm - cracked throttle, no prime. It will be appear slightly flooded. Burning autofuel, I also shut off the fuel & run the carb bowl dry if it won't be flown for a week or more. Fresh fuel in the bowl & primer really helps. |
#26
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A strange richness...
Burning autofuel, I also shut off the fuel & run the carb bowl dry if
it won't be flown for a week or more. Fresh fuel in the bowl & primer really helps. I've run over 6500 gallons of mogas through Atlas, and he (the plane, that is) was run on exclusively mogas by previous owner(s) for almost 10 years. I've never heard of what you're talking about before. Are you saying that mogas starts to go bad after a WEEK? -- Jay Honeck Iowa City, IA Pathfinder N56993 www.AlexisParkInn.com "Your Aviation Destination" |
#27
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A strange richness...
I've never heard of what you're talking about before. Are you saying
that mogas starts to go bad after a WEEK? Summer gas v winter gas? (different vapor pressures) http://www.epa.gov/otaq/volatility.htm Remember that autogas does not have the stabilizers that avgas has. http://www.chevron.com/products/prod...ationfuel/8_ag _perf.shtm http://www.chevron.com/products/prod...ationfuel/11_a g_refining.shtm www.eaa.org/education/fuel/autogas_vs_avgas.pdf http://www.avweb.com/news/maint/187232-1.html http://www.generalaviationnews.com/e...lasso?-token.k ey=8901&-token.src=column&-nothing |
#28
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A strange richness...
Jay Honeck wrote:
I've never heard of what you're talking about before. Are you saying that mogas starts to go bad after a WEEK? If I don't purge the float bowl, starting cold w mogas is less predictable, and a bigger slug of fuel will puddle and remain in the intake manifold after startup. This slug goes thru the engine with a lot of burping & coughing etc as the throttle is first advanced after starting. I consider this tacky. I don't like flying behind engines or with pilots that don't start well - just on general principle. This doesn't happen if the engine is warm as the oil heats the manifold which minimizes fuel condensation. Mogas has a wider distillation temp range than a/c fuel. The light components of mogas will more easily evaporate from the bowl leaving you with a more-like-kerosene mixture for starting, depending on how long it has been sitting. Yes you can usually get things going, but it does mean grinding the starter more. In the fifties farmers would burn something we called "Powerfuel" in their carburated tractors. I worked in a garage & we could never get them going without priming with fresh gasoline. My lawn mowers like this too. Especially my snow blower. Can aircraft be far behind? |
#29
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A strange richness...
On 26 Apr 2006 20:48:16 -0700, "nrp" wrote:
Jay Honeck wrote: I've never heard of what you're talking about before. Are you saying that mogas starts to go bad after a WEEK? If I don't purge the float bowl, starting cold w mogas is less predictable, and a bigger slug of fuel will puddle and remain in the intake manifold after startup. This slug goes thru the engine with a lot of burping & coughing etc as the throttle is first advanced after starting. I consider this tacky. I don't like flying behind engines or with pilots that don't start well - just on general principle. This doesn't happen if the engine is warm as the oil heats the manifold which minimizes fuel condensation. Mogas has a wider distillation temp range than a/c fuel. The light components of mogas will more easily evaporate from the bowl leaving you with a more-like-kerosene mixture for starting, depending on how long it has been sitting. Yes you can usually get things going, but it does mean grinding the starter more. In the fifties farmers would burn something we called "Powerfuel" in their carburated tractors. I worked in a garage & we could never get them going without priming with fresh gasoline. My lawn mowers like this too. Especially my snow blower. Can aircraft be far behind? Thanks that makes a lot of sense. I've aways found my engine 0-290D to be harder to start with autoffuel than 100LL even though it runs much better on it. I amost always have my engine stall after about 20 seconds during a cold start regardless of priming or throttle pumping. |
#30
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A strange richness...
: In the fifties farmers would burn something we called "Powerfuel" in
: their carburated tractors. I worked in a garage & we could never get : them going without priming with fresh gasoline. My dad's 1939-ish Oliver-60 Row Crop (that he still uses to plow snow and run the PTO pump for the logsplitter) was one such creature. It would run on either gasoline or kerosene ("farm-fuel" is what I'd heard it called). That tractor's a hoot to drive around. -Cory -- ************************************************** *********************** * Cory Papenfuss, Ph.D., PPSEL-IA * * Electrical Engineering * * Virginia Polytechnic Institute and State University * ************************************************** *********************** |
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