C Model Engine Starts

[Lowbid]

Since purchasing 6 mos. ago, my engine was always hard starting cold or hot. I have recently been starting without using the booster pump and the starts have been noticeably easier and quicker. 3 pumps of the throttle and it pops right off. Anybody else notice the same thing?

[Sabremech]

Typical procedure on my C is, mixture rich, boost pump on, throttle two full pumps, leave throttle about 1/4 inch in, start. Never had an issue hot or cold.

[Lionudakis]

Mine is the same as Sabremech, but mine starts rougher than I'm used too, engine mounts are fairly new, it just feels rougher through the airframe than most. I started a friends J the other day and it was noticeably smoother. Runs smooth though

[omega708]

I use a similar technique in my 67C ( cold starts )

Warm weather:

Mixture full rich, boost pump on, 3 pumps of the throttle, boost pump off, throttle cracked about 1/4", mixture full lean, crank... As soon as it starts to catch I ease the mixture forward and adjust the throttle as necessary.

Below 50 degrees F:

Same except I have to pump the throttle 6-8 times.

I've found that this procedure produces much smoother starts of the engine, especially in cold weather.

[Jerry 5TJ]

The carb is below the engine, so perhaps you need to "pump" the throttle to help get some fuel vapor up into the intake tubes.

I use the "Sabremech technique" (above) to start my M20C.

Two years ago starting the "C" got considerably harder for a few weeks, which I put down to cold weather...then the left mag failed completely. Two new rebuilt mags and it was back to starting like its old self, hot or cold.

[BigTex]

Mine fires right up... Boost pump on and when pressure is built up, I shut it off. Then two pumps of the throttle. I make sure is see the fuel pressure drop with each pump. Crack the throttle a 1/4 inch had the fires right up. Then I lean it pretty aggressively.

[rbridges]

Mine fires right up... Boost pump on and when pressure is built up, I shut it off. Then two pumps of the throttle. I make sure is see the fuel pressure drop with each pump. Crack the throttle a 1/4 inch had the fires right up. Then I lean it pretty aggressively.

that's exactly how I do it. when it's already warm, I only prime it once.

[lahso]

In my 1966 C, I pump throttle once for the first start of the day, crack the throttle, crank and go. If multiple cranks for a day, I only have to crack the throttle (unless it's been sitting for 6-8 hrs).

[Oscar Avalle]

I had a similar problem with my M20C. Since I have the LASAR ignition, she starts up without any problems. Mix rich, Fuel pump on, pump throttle twice (depending on the temperature) and she fires up

[Apollo]

Master on. Mixture Full Rich. Boost Pump on until fuel in the middle of the green arc. Boost pump off. 3 Throttle Pumps on a normal day (7 for a cold winter). Start.

[AmigOne]

First time start on my 68 M20C like everybody else, no pumping required up to one hour after shut down most of the year. If really cold maybe one pump (no boost pump) within one hour after shutdown. More than that needs boost pump.

[hindsight2020]

Um, I don't know much about the particular carb on the mooneys, but assuming they are equipped with accelerator pumps, the whole business of pumping the throttle before cranking in an updraft carburetor setup is an engine fire waiting to happen in the unfortunate event of a backfire. Does the 20C have a primer? I'd be using that instead.

I used to pump indiscriminately before and during engine cranking and then someone illustrated the pitfalls of doing so in the updraft carb. Cranking while pumping will help you get gas upstream, but pumping BEFORE cranking is just pooling fuel on the bottom of the box and setting you up for a bad day.

At least on my warrior I utilize the primer with the boost pump on, and no throttle movement. It does the trick hot or cold. But again I'm not sure if the Mooneys have primers.

[Hank]

Mooneys do not have primers, just an auto-enrich at full throttle.

Also, my Owners Manual says Boost Pump--ON, Throttle--Pump two times (3 to 5 times in cold weather), Ignition--ON, Push to Start.

Procedures vary between makes and models. Only 2 backfires in 5 years, no flames ever. The carbureted C model was the highest (2nd highest?) production model, thousands of engine starts annually. If the procedure was dangerous, it would have been noticed decades ago.

[carusoam]

It was difficult to get fuel from the carb to the cylinders in cold weather. A primer would have been a nice addition. Cold days got a lot of pumps of the throttle.

Temperatures below 20 deg F required pre-heat. In NJ, few days are that cold.

My 65C followed Hank's experience.

Best regards,

-a-

[mike28w]

My approach pretty much mirrors Sabretech's..... ( me thinks that he has a lot on the ball )..... Only thing to mention is that especially when it's cold, ( after a couple of pumps from the throttle) I make it a point to wait 30 seconds or so . I believe that it gives the fuel a little time to vaporize...... When I first heard about waiting , I was skeptical, but it really does seem to help.YMMV, of course.

PS: Why in the world didn't Mooney just install a primer system ??? I can't believe that it would add more than a pound or two.....mike

[Apollo]

Okay guys I hate to bump this but I apparently need some clarification on starting my mooney in the cold.

 

 

This weekend we flew to KSAF Santa Fe NM. It was 26F when we were trying tot ake off. The prop kept spinning, and tried to catch every now and then, but I ended up having to get a jump to start the airplane.

 

 

Heres what I normally do:

 

Cold Start: Master on, Fuel pump on, then off (green arc), then 7 pumps of throttle, 1/4inch then start.

No Dice today:

 

 

Okay, well then I started thinking about it and somebody pointed out that I had gas on the nose gear. Well, that's typically in the cold since we prime it so much.

I tried again, same procedure, including the 7 pumps. No joy.

 

 

 

What I;'m asking is this: After you do the 7 pumps, are you ever supposed to try and prime it again with the throttle? Or should all my subsequest attempts to start(maybe the next 3 or so) be with the throttle just cracked up a 1/4inch?

 

 

 

I took the battery voltage from 12.8 down to 11.8 when trying to start it in the cold before I got a jump. Hope I didn't ruin that battery as we just put in a new one a couple of months ago :|

[mike28w]

  That's seems like a lot of pumping.....   If it's dripping , I can't see how that can be good.  I've only seen one engine compartment fire and it was memorable ! ( and it had been dripping fuel before it started burning)    Glad it wasn't my bird.....

 

  If I had to pump the throttle that much, I think I would be talking to my mechanic to find out why.....jmo....mike

[Apollo]

Yeah normally this bird is kept in 50+F weather at all times. So this 'cold start' thing may be something I've got wrong in my head.. Looking for experiences.

[carusoam]

Cold temp starts with a carbed M20C is excess fuel everywhere. It is not as safe as firing up a modern car, but that's the process...

100LL fuel does not evaporate like automotive varieties...

It is a real challenge to get some to evaporate while pouring excess on the ground.

Ten blades go by, one cylinder fires. This is the hint that you've got it right. Pump the throttle again, fire it up again, six blades go by, one cylinder fires.....

It continues in this fashion until enough cylinders fire to keep the engine running.

This is the experience of my old ’65 C.

It would be good to get a primer pump if you can(STC?). Or pre heat to improve the evaporation rate / partial pressure of 100LL.

You may start a thread on primer pumps for carbureted Mooneys. I don't remember anyone putting one on. They are better than using the accelerator pump ad can be used independently of the throttle itself...

Bes regards,

-a-

[yvesg]

Okay guys I hate to bump this but I apparently need some clarification on starting my mooney in the cold.

 

 

This weekend we flew to KSAF Santa Fe NM. It was 26F when we were trying tot ake off. The prop kept spinning, and tried to catch every now and then, but I ended up having to get a jump to start the airplane.

 

 

Heres what I normally do:

 

Cold Start: Master on, Fuel pump on, then off (green arc), then 7 pumps of throttle, 1/4inch then start.

No Dice today:

 

 

Okay, well then I started thinking about it and somebody pointed out that I had gas on the nose gear. Well, that's typically in the cold since we prime it so much.

I tried again, same procedure, including the 7 pumps. No joy.

 

 

 

What I;'m asking is this: After you do the 7 pumps, are you ever supposed to try and prime it again with the throttle? Or should all my subsequest attempts to start(maybe the next 3 or so) be with the throttle just cracked up a 1/4inch?

 

 

 

I took the battery voltage from 12.8 down to 11.8 when trying to start it in the cold before I got a jump. Hope I didn't ruin that battery as we just put in a new one a couple of months ago :|

About your procedure:

Cold Start: Master on, Fuel pump on, then off (green arc), then 7 pumps of throttle, 1/4inch then ...

Are you sure that you pump while the fuel pump is off? Here I pump when it is on then turn it off. I am in Canada and the most pumps I would do is 6 however I would always pre-heat when the temp is below 32 F.

Yves

[Hank]

I cold-start mine by running the pump until fuel pressure stabilizes, then off. Mixture rich, pump it several times [colder = more pumps]. Then I give the fuel time to vaporize--wind & set the clock, put on headset, do anything to kill 60 seconds or so. Then turn & push. Sometimes have to let her turn and turn, get a cough, let go; if she won't run, let her sit a minute and try again. It may take several attempts if you don't pre-heat.

[Apollo]

When you say try again, do you mean the entire procedure, including several more pumps?

Sent from my iPad using Tapatalk HD

[Hank]

When you say try again, do you mean the entire procedure, including several more pumps?

Sent from my iPad using Tapatalk HD

 

Yes, when it's cold [~freezing or below]. If you start smelling fuel, then do a Flooded Start.

 

Remember to not crank it for too long [less than 30 seconds per attempt], and let it rest between attempts to cool the starter. No, I don't go the book's 3-5 minutes between attempts, especially if she is coughing and trying to run.

[Z W]

On mine, for a very cold start such as 26 dF, I will do 5 pumps, then crank.  The engine will catch, spin for a few revolutions, then die.  Next time, I do 7 pumps, and it will fire and keep running.  I developed this because if I ever manage to get it flooded, I cannot get the thing to start.  The flooded start procedure has never worked for me on this plane, and I've successfully used it on other models.  Go figure.  If you go straight to 7 or 8 pumps, sometimes that's too much (e.g. it's 26 dF but you are parked facing the sun and your engine isn't that cold) and it floods it.  Working your way up to 7 or 8 pumps avoids the flooded situation.

It actually reminds me of starting a weedeater, where you do a couple pulls at full choke for a false start to flood the engine.  This is the opposite, since it's actually firing while too lean, but for whatever reason it works on my 68 C model.  And sometimes, it turns out 5 pumps was the right number, despite the cold, and it just fires up and goes.

 

I've always done this with the fuel pump on, even while pumping and cranking.  My POH doesn't say anything about turning it off after fuel pressure comes up.

 

Never noticed gas dumping out the bottom of the engine with this procedure and it works even when the engine is very cold.  I do try pretty hard to use the pre-heater when temps get below 40 dF.

[DXB]

I need to revive this thread so I can figure out how to cold start.  All 15 hrs in my 'C have been in the northeast winter so far, but I've always had a space heater blowing into the cowl the night before.  If I do this, it starts instantly on the coldest day no matter what procedure I use (typically mixture rich, boost pump on briefly to get pressure in green arc, 3-4 pumps throttle and then crack open, crank).

 

This weekend it was a bit warmer- got down to 35 at night and was in the mid 40s when I got to the field.  I hadn't put the heater on, and I was wondering how it would go.  Not too well, it turns out.  I tried same process as above but used 5 pumps of the throttle, cranked for 15 sec- nothing.   Added four more pumps. Tried again- nothing. Sat on my hands for 30 sec, tried again- nothing.  Sat on my hands for two minutes, used boost pump again, 7 pumps, cranked 15 seconds- nothing.  Got out of plane, made sure nose gear not sitting in a puddle of fuel, tried flooded procedure- nothing.  Grew despondent, considered giving up and taking up gardening instead.  Added 2-3 pumps again, cranked 15 seconds- seems to sputter a bit but won't start.  Sat on my hands again for 2 full minutes, no pumps, and it started instantly.

 

It's clear I don't know what I'm doing after the standard procedure won't work, and it was dumb luck that I ultimately got it started.  Next time I suspect I'll go up in flames or cause other damage.    What do other folks do when it doesn't start cold after the first couple of tries?  Is there any way to know if it is too lean and I should pump more, or if it is flooded (other than the smell of fuel and seeing it on the nose gear)?