Scary moment today

[Seanhoya]

Par,

 

If the engine starts to turn over and coughs, I might lean by 1".  Usually, when it is really cold, though, I stop, let the engine sit for 5 minutes, and start the whole procedure over.

 

BTW - have you looked into the possibility that all 8 plugs aren't firing?  I ask because there is only so much technique can make up for, and it sounds like you might have an actual ignition problem.  I say this after having changed every piece of my starter system out to finally realize that my starter switch (the actual switch) was bad.

 

Or maybe you have an issue with your carbuerator - was it rebuilt during the last overhaul?  Because I don't think accessories have to be rebuilt, and in my case, no accessory on the engine was (yes - I have subsequently changed out my carbuerator, oil cooler, starter, battery, and replaced my alternator).

 

You've got a lot of recommendations here.  An easy answer is to put the plane in a heated hangar.  But it sounds like you might not have worked out all of the bugs with the plane yet, and my gut feeling tells me something else is going on with the engine....

 

Sean

[goterminal120]

On a carb carb automobile when you pump the gas the spray of fuel goes down the manifold.....On a plane the carb is upside down on the bottom of the engine and if pumped without cranking the engine the fuel runs out of the carb down inside the airbox/carb.

The easy way to stay a carb plane and be darn sure it's not flooded is to never get it flooded. Just crank the starter (at this point it lean and no fuel is present then pump the gas while cranking once enough fuel reaches the cylinders it will fire and there is no chance of it getting flooded.

I keep pumping the damn throttle until it starts. It's next to impossible to flood a engine from pumping/priming while there engine is cranking.

Hope that helps. But never ever EVER EVER pump the throttle on a plane without cranking the engine while doing so. All that has to happen is have the engine backfire out the carb and your on fire if fuel is laying in airbox/cowl dripped all over tire!

 

 

aaronk25 is absolutley correct, you can't beat physics or gravity. The gas coming out of the accelerator pump is more of a stream than a mist and vaporizes in the intake tract as it is pulled through by the vacuum created by the piston on the intake stroke. On startup vacuum is low but enough to draw, without the engine turning that gas just falls to the floor. That wait time Hank refers to is that gas in the air box evaporating, then drawn in as a vapor. Effective but unnecessary.

  As far as cold starts, again as aaron states, pump as you crank. Only difference being I give the starter a break if it doesn't start on the first few blades.  Unless you are in extreme cold pre heat really isn't that necessary as long as your using a multi viscosity oil. You don't pre heat your car and it last for tens of thousands of hours. A car engine has tighter tolerances so in theory it should wear faster in the same conditions.

  This is my first post and Im sure it will get flamed for being a nobody. For reference, I am an A&P IA have been working on aircraft for over thirty years from UH-1s to L1011. I currently own a 172 and a 68 m20c.

 

[Seanhoya]

Goterminal,

 

Welcome!  In terms of being new, just avoid the use of exclamation points, fonts, colors, strong language, and absolutes(comments like "Never, Never, Never..."), and all will be well!

 

...and I would also avoid ever commenting on Lean of Peak operations....

 

Sean

[bonal]

Welcome Goter, I used to do the crank and pump method and mine would sometimes take forever to start and when it finally did even with an aggressive lean I would have plugs that were so fowled (spelling) that even a full power run up would not clear them. Once I started doing the pump wait and crank method it never takes more than 3 blades to start. As for fuel in the box well yes it does gather there but if you don't pump it to many times you get just the right amount so it doesn't drain out and with a 30 plus second sit it's all vaporized and gets pulled into the engine on the first intake. Also since there is no fuel in the cylinder there is virtually no chane of a backfire.

Also we love to see photos of Mooney's so give us the pleasure and share a few of yours.

[carl]

Hello 

carusoam  said "Go electric preheat if you can. The ability to call on the cell phone for pre-heat is magical."

       

Tomorrow it is going to warm up to 15 degree F and have calm winds, I want to fly. 

I go to the airport and plug in my tannis heater , Then I go home , come back in a hour or so. 

 

I found the WeMo switch, bought it , the hanger doesn't have WiFi,so it doesn't work, I took it back.

 

What other choices are out there ?

 

Carl 

[aaronk25]

My Mooney cranks like my old truck--step on the gas a couple of times then turn the key. This won't work on fuel injected trucks or Mooneys.

The OPs situation was unfortunate AND unusual. It may be more common in Cessnas and Pipers, I don't know, but their induction systems are different from ours (par's and my own; injected Mooneys are a completely different animal).

Without pumping the throttle, we will be cranking an engine with no fuel, a losing proposition. No primer, remember?

You keep talking about injected Mooneys not sure I follow you? I have a injected mooney that I own but I'm not referencing were talking about carbs right?

I never used the primers on a cessnas or pipers either because they only prime 3 of the 4 cylinders (not a big deal) but mainly because I fly in several different carb planes and one needs 2 prime and the other 6 primes and it just takes longer.

So when you turn the key to crank the engine you could, inside of 2 seconds of cranking literally pump the throttle 3 times if you really need to. In 5 seconds I could pump it 10 times which is way to much fuel so the point is this is incorrect:::: "Without pumping the throttle, we will be cranking an engine with no fuel, a losing proposition. No primer, remember"....

I'm saying pump the same amount of fuel in that you normally would but get the velocity going though the carb first so you don't catch on fire in the event of s back fire. The OP plane isn't the first plane to catch on fire because of this poor design and there have been others that have burned to the ground because of this.

When fuel is presented to moving air it helps atomize it, which is needed when cold. If you just pump it without cranking it goes squirt against the side of the carb and runs down. The Reid Vapor Pressure of our fuel is very low and not reformulated for winter which isn't the case with auto fuel so the colder it gets the less atomization you experience.

So if it's cold and your counting on that puddle of fuel thats running out of the carb and dripping on the tire to create enough explosive vapors to start the engine.....good luck., but if the engine backfires that fuel will light and your on fire!!!!!

[aaronk25]

Goterminal,

Welcome! In terms of being new, just avoid the use of exclamation points, fonts, colors, strong language, and absolutes(comments like "Never, Never, Never..."), and all will be well!

...and I would also avoid ever commenting on Lean of Peak operations....

Sean

NEVER,NEVER,NEVER,!!!!!!!!!!!!!!!!!!!!!!

[carusoam]

Carl,

I am using the switchbox...

http://switchboxcontrol.com/the-switch-box/

good for everybody. No EE degree required.

Noterm, welcome aboard!

We have the power of MooneySpace working on this chilly Sunday morning.

Best regards,

-a-

[bonal]

Aaron you make good points and I think what's important is to not over do it. So what your saying is I should run lean of peak. All kidding aside. I spent the first few months pumping while cranking and I would get to the point of cussing at my engine also had backfires using this technique and as I mentioned above really fowled plugs. If it's cold all you do when you crank and pump is pull raw fuel into the cylinder which has not atomized gets all over the plugs which can prevent spark. I will stick to what works for me pumping and waiting mine starts so easy you would think it a brand new car. As for back fires we'll knock wood never so much as a hiccup

[Marauder]

Carl,

I am using the switchbox...

http://switchboxcontrol.com/the-switch-box/

good for everybody. No EE degree required.

Noterm, welcome aboard!

We have the power of MooneySpace working on this chilly Sunday morning.

Best regards,

-a-

Chilly?! It was a balmy 1°F when I got up this morning. I was expecting a negative number!

[Marauder]

Goterminal,

Welcome! In terms of being new, just avoid the use of exclamation points, fonts, colors, strong language, and absolutes(comments like "Never, Never, Never..."), and all will be well!

...and I would also avoid ever commenting on Lean of Peak operations....

Sean

Or whether you should practice touch and goes in a Mooney

Or if you should land with no flap, approach flaps or full flaps

And never, ever bring up that a 40 year old Bendix King HSI is like a Swiss watch!

[fantom]

But there is 100% agreement about using CamGuard

[HRM]

As I mentioned earlier, this whole issue (cold carb Mooney starting) has a parallel in FI Mooney hot starting. Get either topic going, as evidenced by this thread, and you will receive a plethora of techniques, processes, algorithms, expensive do-dads ("The SwitchBox"), religious incantations and etc.

 

One important factoid that goes with each issue is that of a robust engine. What I have found over the years is that when my engine is well tuned and fuel and spark systems are optimal, she starts instantly regardless of the weather if the POH procedures are followed.

[Hank]

Carl,

I am using the switchbox...

http://switchboxcontrol.com/the-switch-box/

good for everybody. No EE degree required.

Noterm, welcome aboard!

We have the power of MooneySpace working on this chilly Sunday morning.

Best regards,

-a-

This is a wonderful product, only requires cell service at your hangar. If the included card doesn't have service, you can swap it easily for another brand. No more driving back and forth to the airport! Really makes winter flying nicer.

I had cranking trouble a couple of years ago. New plugs helped for a while, then no more. Deliberately flooding the engine yielded no dripping fuel, so I sent the carb off fir overhaul. Temporary improvement again. Put in a new Concorde battery, the doggone prop spun fast enough to taxi, but still hard to start. Finally went through the shower of sparks. Starts are blissfully easy now.

[par]

Well, I wish I could have gone and tried some of these techniques yesterday but i'm sure I'll end up waiting at least a week if not longer for the shop to take a look at the damage. I do wonder about the wear and tear that cold temps can create on startup but then again, like Goterminal said, my car engine should have worn out by 100K miles since they experience 2 to 3 cold starts in similar temps each day. The same can be said for the planes parked at the flying club that do not have any kind of engine heating capability and they operate in the same weather all the time. I can't image they are tearing the engine down every 500 hours as a result.

 

I will have the mags rebuilt during the annual at the end of the year along with the carb. I don't think either has been done in at least 10 years. The pistons only have about 50 hours on them STOP(2005). I think i'm going to need a new air filter at the very least along with some new scat tubing. I don't know if the fire got hot enough to melt any of the O-rings in the carb but I will need to wait and see. No matter what, I am going to be extremely cautious from here on out with the start.

[par]

This is a wonderful product, only requires cell service at your hangar. If the included card doesn't have service, you can swap it easily for another brand. No more driving back and forth to the airport! Really makes winter flying nicer.

I had cranking trouble a couple of years ago. New plugs helped for a while, then no more. Deliberately flooding the engine yielded no dripping fuel, so I sent the carb off fir overhaul. Temporary improvement again. Put in a new Concorde battery, the doggone prop spun fast enough to taxi, but still hard to start. Finally went through the shower of sparks. Starts are blissfully easy now.

 

What is this "shower of sparks"? 

[jetdriven]

You keep talking about injected Mooneys not sure I follow you? I have a injected mooney that I own but I'm not referencing were talking about carbs right?

I never used the primers on a cessnas or pipers either because they only prime 3 of the 4 cylinders (not a big deal) but mainly because I fly in several different carb planes and one needs 2 prime and the other 6 primes and it just takes longer.

So when you turn the key to crank the engine you could, inside of 2 seconds of cranking literally pump the throttle 3 times if you really need to. In 5 seconds I could pump it 10 times which is way to much fuel so the point is this is incorrect:::: "Without pumping the throttle, we will be cranking an engine with no fuel, a losing proposition. No primer, remember"....

I'm saying pump the same amount of fuel in that you normally would but get the velocity going though the carb first so you don't catch on fire in the event of s back fire. The OP plane isn't the first plane to catch on fire because of this poor design and there have been others that have burned to the ground because of this.

When fuel is presented to moving air it helps atomize it, which is needed when cold. If you just pump it without cranking it goes squirt against the side of the carb and runs down. The Reid Vapor Pressure of our fuel is very low and not reformulated for winter which isn't the case with auto fuel so the colder it gets the less atomization you experience.

So if it's cold and your counting on that puddle of fuel thats running out of the carb and dripping on the tire to create enough explosive vapors to start the engine.....good luck., but if the engine backfires that fuel will light and your on fire!!!!!

 

Well said, Aaron. As long as the air is moving through the carb, pumping the throttle is relatively low risk. That's the funny thing about risk, it isnt always properly quantified until your airplane is on fire, or you're sliding down the runway on your belly.

 

So, what;'s wrong with, say, hitting the starter and pumping it 3 times very quickly, then if it starts right up, great. If not, let it sit 30 seconds, the fuel vaporizes (inside the cylinders, not the airbox), then start it up. Mimic the operation of a real engine primer, so to speak.

 

@Seanhoya mentioned that maybe all 8 plugs are not firing. That's correct. only 4 plugs fire, only the left mag has the impulse coupler. How many LH Slick mags have we changed at the shop because an airplane won't start? About 6 or 7. Its really showing up in the fleet. Either the coil breaks down, or the rotor falls apart. Or something else, but I'd have a look inside.

[Hank]

What is this "shower of sparks"?

The Shower of Sparks is what vibrates and buzzes when you push the key in, and is an integral part of starting your Mooney. I'm not knowledgable enough to go into detail about its operation.

When you crank the engine, one magneto (usually right) is blocked and the other (left) magneto fires with delayed timing, near when the piston reaches Top Dead Center (it's highest point before starting down). This allows the fuel to burn and push the piston down. Normally our engines fire when the crankshaft is 25° rotation BEFORE TDC, and the piston is moving much faster. The SoS causes additional sparks, above and beyond normal operation, to help catch the fuel vapor and get the process going.

Turning the key arms the magnetos, pushing it in starts the Shower, releasing it goes back to normal operation. You should hear a buzzing noise when pushing (leave your headset off for this). Should be a steady buzz, and you may notice a little vibration, but it will probably be masked by the rotating prop. If you don't hear it, or if it's not steady, then the SoS needs help. Your A&P should be able to discuss this with you in somewhat more detail.

Best of luck, and hope you're back in the air soon!

[Hank]

 

So, what;'s wrong with, say, hitting the starter and pumping it 3 times very quickly, then if it starts right up, great. If not, let it sit 30 seconds, the fuel vaporizes (inside the cylinders, not the airbox), then start it up. Mimic the operation of a real engine primer, so to speak.

 

Two things are wrong with this: 1) it won't crank like this in cold weather, the fuel is too dense with depressed vapor pressure; 2) it's not mimicking "real engine primer," which puts fuel into the system with the crank still and magnetos de-energized. Back when I took lessons, we'd prime the ol' Cessner and then wait a while before cranking. That's what I do now pumping the throttle. Same same, just no separate primer plumbing.

One other thing wrong with your idea: it directly contradicts a very specific and explicit procedure published by Mooney. See Post #2 and read the attachments from my M20-C Owners Manual, copyrighted 1970. If it was a problem, they wouldn't have published this exact procedure for over 20 years, and surely some lawyer by now would have forced a change if the FAA didn't do something first.

Strange, unusual and rare events happen sometimes. I remember induction fires being covered as a student pilot--keep cranking and hope the airflow puts it out; if not, shut off fuel, pull mixture and crank some more; last option, abandon ship.

[triple8s]

I dealt with this for 5 seasons and was one reason I wanted a fuel injection on my C model, didnt want the angle valve engine, just wanted FI. The later model Skyhawk had a parallel valve Lyc with FI. Anyhow, I had the cold weather start issues and could always get mine started by...... run the boost pump and mixture full rich pump 5-10 pumps, leave the throttle full open, take key out of switch and lay on the glare shield in my sight, get out and slowly pull it through about 10 blades. I then taking my time would get back in and give it another half dozen pumps with boost on, get back out and with throttle open i pull through another half dozen blades. Again taking my time so excess fuel would evaporate I'd work my way back into the cockpit. Mixture full rich, boost on, 2 or 3 pumps close throttle completely then engage starter. The key for my C was to NEVER open the throttle AT all when cranking. Letting the thing set there after pumping and pulling through made the difference on my plane, i think it let the fuel vaporize/evaporate. I did see a C model someone had put a primer on it, didnt ask about an STC but it had a primer on it.

[jetdriven]

Two things are wrong with this: 1) it won't crank like this in cold weather, the fuel is too dense with depressed vapor pressure; 2) it's not mimicking "real engine primer," which puts fuel into the system with the crank still and magnetos de-energized. Back when I took lessons, we'd prime the ol' Cessner and then wait a while before cranking. That's what I do now pumping the throttle. Same same, just no separate primer plumbing.

 

Its not the same, pumping the throttle on a still engine puts fuel into the throat of the carburetor VIA the accelerator pump, which immediately runs out the throat of the carburetor, into the airbox, and into the cowling.  if the engine is cranking, the fuel is getting pulled into the cylinder head and the combustion chamber, where it cant leak out.

 

 

One other thing wrong with your idea: it directly contradicts a very specific and explicit procedure published by Mooney. See Post #2 and read the attachments from my M20-C Owners Manual, copyrighted 1970. If it was a problem, they wouldn't have published this exact procedure for over 20 years, and surely some lawyer by now would have forced a change if the FAA didn't do something first.

 

Cessna didnt bring back the 210 series after 1996. Not because it was a deficient design, far from it. Because they have learned a few things since the last go-round and they would beef up the wing and some other structure. Which to lawyers is tantamount to admitting the earlier airplanes were deficient, and incurred new liability. They had been sued before and always asserted the airplanes were safe. So no new 210. And no beef up kit for the older ones. Perhaps the same thing here. Saying "dont pump the throttle unless cranking" means "install this primer kit" which doesnt exist, and perhaps letting sleeping dogs lie is easier than creating a whole new set of new procedures for a plane they dont make any more.  Perhaps not, but I guess what I'm saying is procedures get rewritten all the time as service history uncovers deficiencies and new incidents. United Airlines began opertating the 727 in 1963. In 2001 they were still regularly issuing flight ops manual changes. You'd think they'd have learned everything there was to know in the first 38 years.

 

Strange, unusual and rare events happen sometimes. I remember induction fires being covered as a student pilot--keep cranking and hope the airflow puts it out; if not, shut off fuel, pull mixture and crank some more; last option, abandon ship.

 

If something I was doing had even a minute possibility of a total hull loss I'd do whatever it takes to mitigate that, if there was any alternate procedure available.    In Houston, that I know of, 3 airplanes burned to the ground from induction fires on startup.  The latest was a Piper PA28. the cause? Pumping the throttle to prime it instead of the primer. 

[aaronk25]

Yep...that's why I made a few attempts to try to offer some info on the subject....scary stuff.

[carusoam]

Thought the fire extinguisher would have been more effective than that....( video posted by Byron)

Gasoline is pretty powerful stuff.

Oh, the aviationanity....

Ugh,

-a-

[Guest]

The problem with priming with the accelerator pump in the carburetor is that the first volume of fuel hits the throttle plate and immediately runs back into the air box. As the throttle plate opens fully the stream of fuel hits the top of the intake plenum in the engine, it too runs back down the throat of the carburetor and collects in the air box. Repeating the process 2-3 more times builds quite a puddle of fuel. Byron's video shows what can happen next.

The conventional priming system will prime 3 of 4 cylinders with a special priming nozzle which atomizes the fuel in a very fine mist delivered to the intake port. In the event of over priming, 3 cylinders may be flooded and the fourth will have none, leaving a chance for it to fire and start the engine.

Clarence

[DXB]

My sympathies to the OP; with even less experience than his, the situation could easily have been mine as I fumble through my first cold winter starts. This thread, while informative, has left me terrified both to follow the POH and to do anything not in the POH (except preheat- I'm 100% into that!).   Right now on cold days I'm running boost pump for a few seconds until pressure needle is in the green arc, pumping throttle 4 times, then cranking immediately.  This works 1/3 of the time, but I'm pretty lost on what to do when it doesn't work, and I'm not learning much from the failed experiences.   In my mind, some options are:

 

1. pump throttle again a specified number of times and then try cranking (perhaps also giving me a chance to re-enact the entertaining Piper video above)

2. pump a couple more times while cranking  (although this clearly didn't work out for the OP, maybe there's less chance of fire than #1?)

3. don't pump throttle, wait several seconds for fuel to vaporize, and try again

4. pump throttle, wait several seconds for fuel to vaporize, and try again

5. wait for 5 minutes after 1 or more failures (as POH actually suggests to avoid overheating starter), start over either with POH technique or another technique.

6. some other approach I've as yet to envision

7. give up and find a less engine fire-prone hobby, like sudoku or knitting

 

I'd be curious to hear specifically how the experienced folks approach failed initial cold start attempts with the carbuerator.