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  #21  
Old 06-20-2017, 10:38 AM
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Bubblehead Bubblehead is offline
 
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I agree on the battery. I use the Odyssey 680 in my -8 with IO-360. The battery is doing fine.

I used to go WOT Full Rich and boost pump to a count of 5 then MCO for a hot start. Bring the mixture forward slowly and it would usually start just fine.

I now do the lean to rich that DanH described and it works 98% of the time with just a few blades of turning. Told a Bonanza guy about it once at the fuel pumps and he now hot starts that way.

BTW I found that procedure on the Mooney Pilot's Association website. There is a lot of good information there.
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  #22  
Old 06-20-2017, 10:55 AM
vic syracuse vic syracuse is online now
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Quote:
Originally Posted by erich weaver View Post
Im not criticizing the above hot start techniques; whatever works, right? I do find it odd however that folks are recommending against using the boost pump just prior to starting. I use mine, per the procedure recommended by by AFP. The logic seems sound to me: Circulate cool fuel from the tank through the system with the purge value open to get rid of the vapor while avoiding flooding the engine.

erich
The starting procedure IS different with the AFP and a purge valve. With the typical Bendix FI you will flood the engine if you use the boost pump on a hot engine and any prime at all.

Vic
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  #23  
Old 06-20-2017, 11:11 AM
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DanH DanH is online now
 
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Quote:
Originally Posted by erich weaver View Post
Im not criticizing the above hot start techniques; whatever works, right? I do find it odd however that folks are recommending against using the boost pump just prior to starting. I use mine, per the procedure recommended by by AFP. The logic seems sound to me: Circulate cool fuel from the tank through the system with the purge value open to get rid of the vapor while avoiding flooding the engine.
I have an AFP with purge valve, and do circulate prior to start, mostly because it runs nice after starting with cool fuel in everything. The Bendix/Precision/Avstar owners don't have a purge valve.

The above procedures work with all constant flow injections. The aux pump can be on or off; the mixture knob controls fuel flow, not the pump.
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  #24  
Old 06-20-2017, 12:09 PM
ssokol ssokol is offline
 
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A few notes on the electronic ignition system...

I pulled out the manual and it turns out I have a Light Speed Engineering Plasma CDI (Capacitor Discharge Ignition). The system was installed in 2001 when the aircraft was being finished.

The control unit was sent back to the manufacturer for an overhaul only a few weeks before the aircraft was delivered, and the main board was replaced. The ignition wiring is also new.
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  #25  
Old 06-20-2017, 12:31 PM
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erich weaver erich weaver is offline
 
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Ok, I dont see where Steve indicated what type of FI system he has, so if it is AFP, perhaps use of boost pump to circulate cool fuel prior to hot start would be a good idea.

erich
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  #26  
Old 06-20-2017, 01:17 PM
ssokol ssokol is offline
 
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I'm afraid I don't know what make / model the FI system is - I can't find any details in the engine log or build log.

Would a purge valve result in the overflow spilling out? I ask because when we tried a flooded start we wound up with fuel dripping out of the bottom of the cowl. I expected to see it coming out of the exhaust...

Please pardon my mechanical ignorance - I'm doing my best to learn as I go.
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  #27  
Old 06-20-2017, 01:42 PM
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Quote:
Originally Posted by ssokol View Post
I'm afraid I don't know what make / model the FI system is - I can't find any details in the engine log or build log.

Would a purge valve result in the overflow spilling out? I ask because when we tried a flooded start we wound up with fuel dripping out of the bottom of the cowl. I expected to see it coming out of the exhaust...
Given the airframe age, probably Bendix RSA-5, maybe a Precision Silver Hawk EX-5. If you had an Airflow Performance system, the cockpit would include a rather obvious purge valve control...a knob, or lever, or something.

Again, it doesn't matter. The purge is nice, but not essential; the ability to circulate fuel before start is only a side benefit, not its prime purpose. Actual start procedure is the same for all types.

Re fuel spillage with a flooded start (i.e. sweep rich to lean), yeah, that's normal, in particular given an updraft intake. The fuel is squirted into the intake passage in the cylinder head, just outboard of the intake valves (most of which are closed), so it runs down the intake tubes and drips from the throttle body into the air filter housing, out a drain hole, down the inside of your cowl, and onto the ground. Another good reason to use the "lean to rich" method.
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  #28  
Old 06-20-2017, 01:48 PM
Chkaharyer99 Chkaharyer99 is offline
 
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Quote:
Originally Posted by ssokol View Post
I'm afraid I don't know what make / model the FI system is - I can't find any details in the engine log or build log.

Would a purge valve result in the overflow spilling out? I ask because when we tried a flooded start we wound up with fuel dripping out of the bottom of the cowl. I expected to see it coming out of the exhaust...

Please pardon my mechanical ignorance - I'm doing my best to learn as I go.
Steve,

Fuel dripping out sounds like a recipe for a fire. Please be careful. This might be an occasion when you want to learn before you go any further.

Here's a little info to read about on the Airflow Performance Purge Value.

http://airflowperformance.com/wp-con...al-8-28-07.pdf

https://www.youtube.com/watch?v=vLC0gryo9oU

Notice in the video the control cable that actuates the purge valve.
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Last edited by Chkaharyer99 : 06-20-2017 at 02:02 PM.
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  #29  
Old 06-20-2017, 03:17 PM
ssokol ssokol is offline
 
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Quote:
Originally Posted by Chkaharyer99 View Post
Steve,

Fuel dripping out sounds like a recipe for a fire. Please be careful. This might be an occasion when you want to learn before you go any further.
I totally agree!

The fuel servo on the FI system on my airplane does not have the purge valve and return pictured in the Air Flow Performance info. That appears to be a much more sophisticated system than I have.
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  #30  
Old 06-20-2017, 03:35 PM
Chkaharyer99 Chkaharyer99 is offline
 
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Quote:
Originally Posted by ssokol View Post
I totally agree!

The fuel servo on the FI system on my airplane does not have the purge valve and return pictured in the Air Flow Performance info. That appears to be a much more sophisticated system than I have.

Nor does mine. Like DanH said, "The purge is nice, but not essential"

If you haven't done it already, consider making a copy of what was said early for inclusion into your checklist, specifically;

Quote:
Originally Posted by DanH View Post
Steve, all successful hot start methods base on a simple concept. The engine will fire when supplied a mixture that is within a fairly narrow range. So, the goal is to sweep the mixture through that range during the start process, either by beginning in a lean condition and moving toward rich, or beginning in a rich condition and moving toward lean. Either way, when you hit the sweet spot, it will light.

Sweep lean to rich (from Nigel):

Throttle open ~1/2 inch
Mixture Idle Cut Off
No priming, boost pump Off
Starter engage
Mixture slowly forward ('slowly' is at a rate that would take you from ICO to rich in about 5 seconds) until it starts, which is usually about mid range.
Throttle as required to set idle RPM
Mixture lean
Boost pump as required to keep it from stumbling if the fuel pressure fluctuates.


Sweep rich to lean (from Randy):

Prime
Throttle full open
Mixture full closed
Start.
As soon as it starts:
Throttle back to hi idle quickly
Mixture about 3/4 open (This is different on all planes)
If you have trouble keeping the idle, run the boost pump after it starts.


As a personal preference, I recommend learning the "lean to rich" method, as it does not begin with the throttle at WOT. The "rich to lean" method becomes a backup plan if it doesn't fire sweeping from lean, as it was left in a rich condition.
Please report back your results.
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