Carb or Fuel injection

[atrosa]

In my quest to find the perfect Mooney for my mission I thought the choice between carb and fi was not even a consideration but now I question myself. So my mission does not require I squeeze every possible knot out of an airplane so 200 hp vs 180 hp in a short body is not a concern. The thought of no carb ice is nice but then I read that FI was more susceptible to vapor lock.  What are the advantages and disadvantages of each fuel delivery method?

[Andy95W]

Carburetor O-360 is much less expensive to acquire and a little less expensive to maintain.  Also less expensive to overhaul, and less expensive if you need cylinder work (the only way to get an IO-360 cylinder is from Lycoming).

Fuel injection is more efficient.  For the same speed, about .5 to 1.0 gallons per hour less.  Also, the ability to fly a little faster.

Carb ice in a Lycoming is almost never an issue, but it is possible.

Hot start difficulties in a fuel injected engine are not only a strong possibility, but also can be a real problem.

[RobertGary1]

23 minutes ago, Andy95W said:

 

Hot start difficulties in a fuel injected engine are not only a strong possibility, but also can be a real problem.

Its been years since I've had any issues with hot starts in FI. New modern starters spin much faster. Worst case I can just flood the engine and then do a flood start. I wouldn't consider that in the equation. 

[A64Pilot]

Hot starts can be learned how to deal with, it’s another technique to learn is all, and motors will differ some, my current J doesn’t seem to suffer from it, I start with mixture in and throttle set for 1000 RPM and she starts right off, others I’ve had required some prime and mixture all the way out, crank until it starts then rapidly in with the mixture.

The only time I’ve seen it be an issue was on float equipped airplanes where you push away from the dock and drift downwind or down stream and really don’t need a start delay, but that’s not us.

‘The only advantage of a carbureted motor in my opinion is many can run auto fuel, but I don’t think that’s an option for us, so in my opinion, carburation has no real advantage over FI.

[Ragsf15e]

2 hours ago, Andy95W said:

Carburetor O-360 is much less expensive to acquire and a little less expensive to maintain.  Also less expensive to overhaul, and less expensive if you need cylinder work (the only way to get an IO-360 cylinder is from Lycoming).

Fuel injection is more efficient.  For the same speed, about .5 to 1.0 gallons per hour less.  Also, the ability to fly a little faster.

Carb ice in a Lycoming is almost never an issue, but it is possible.

Hot start difficulties in a fuel injected engine are not only a strong possibility, but also can be a real problem.

The only way to get NEW cylinders is from lycoming.  You can easily get your old ones OH or buy first run OH.  The cylinders are more expensive, that’s for sure.  OH are about $1800, new are about $2500.

[MooneyMitch]

All my previous Mooneys were injected.

My darling little D/C is such a pleasure, but I’ve had to retrain myself.  I’m probably overly cautious with carb heat, having read most of my adult life of accidents involving carb ice.

Also, I’ve learned to pay much closer attention to fuel tank levels, having transitioned from 100 gallons down to 48 gallons.

All is good and I’m grateful.

[carusoam]

The big difference...

That is noticed every day...

The fuel distribution of the carburetor cannot be controlled... it is what it is...

So...

If you like to run LOP...

and know what your Gami spread is...

And you live on a short  runway....

and your plane is a forever plane....

Go IO360....

There are many forever-planes around here with carburetors....

You won’t be alone when looking for help...

Knowing what carb ice is...

knowing how to avoid carb ice...

Knowing how to get as close to LOP as possible with a carb...

How to get the carb jetted properly, have its float work properly, have its accelerator pump work properly...

 

Carb vs. Fuel injection... one is a bit better than the other...   you won’t go wrong with either...

Maybe one is more right than the other...

Start with an M20C... fly it for a decade... then select your perfect forever-plane...  

It would be really cool if you could see what that perfect Mooney would be... that would fit so many stages of life...

That would be forward thinking...

Best regards,

-a-

[BrianWilkins]

2 hours ago, Andy95W said:

Carburetor O-360 is much less expensive to acquire and a little less expensive to maintain.  Also less expensive to overhaul, and less expensive if you need cylinder work (the only way to get an IO-360 cylinder is from Lycoming).

.....

Hot start difficulties in a fuel injected engine are not only a strong possibility, but also can be a real problem.

You can get IO-360 cylinders from Continental / ECI, and (I think) elsewhere.

[RobertGary1]

50 minutes ago, Ragsf15e said:

The only way to get NEW cylinders is from lycoming.  You can easily get your old ones OH or buy first run OH.  The cylinders are more expensive, that’s for sure.  OH are about $1800, new are about $2500.

Does Superior still make them too?

 

-Robert

[RobertGary1]

2 hours ago, A64Pilot said:

Hot starts can be learned how to deal with, it’s another technique to learn is all, and motors will differ some, my current J doesn’t seem to suffer from it, I start with mixture in and throttle set for 1000 RPM and she starts right off, others I’ve had required some prime and mixture all the way out, crank until it starts then rapidly in with the mixture.

The only time I’ve seen it be an issue was on float equipped airplanes where you push away from the dock and drift downwind or down stream and really don’t need a start delay, but that’s not us.

‘The only advantage of a carbureted motor in my opinion is many can run auto fuel, but I don’t think that’s an option for us, so in my opinion, carburation has no real advantage over FI.

Used to fly a Cub on floats and had to prop it from the back. If it didn't start you were adrift.

-Robert

[A64Pilot]

Just now, RobertGary1 said:

Used to fly a Cub on floats and had to prop it from the back. If it didn't start you were adrift.

-Robert

The Cubs at Jack Browns were hand propped and of course any plane on floats it has be done from behind, they won’t let students hand prop though.

They had it down, seldom was two flips required.

[DXB]

5 hours ago, atrosa said:

In my quest to find the perfect Mooney for my mission I thought the choice between carb and fi was not even a consideration but now I question myself. So my mission does not require I squeeze every possible knot out of an airplane so 200 hp vs 180 hp in a short body is not a concern. The thought of no carb ice is nice but then I read that FI was more susceptible to vapor lock.  What are the advantages and disadvantages of each fuel delivery method?

IO-360 E model with balanced injectors

Pro: 20 more horsepower, can lean an extra 1 gph in cruise running LOP

Con: potentially harder to start hot, risk very bad day from from clogged injector, replacement cylinders cost extra 1K ea over O-360, substantially higher overhaul cost

O-360 C model

Pro: tad more "bulletproof" without injectors, more economical to replace cylinders or overhaul, trivially easy hot starts

Con: 20 less horsepower, can't reliably run LOP, need for more careful attention to CHTs due to crappy baffle design, carb heat management (though pretty much a nonissue, particularly if you have a carb temp gauge)

[Hank]

If you get an O-360, drop the coin and add Carb Temp. Mine is a standalone gage, many are an option on the engine monitor. People are often impressed with how unconcerned I am about the thought of a hot start . . . I just shrug. Cs are magical machines! Even my new CFII tonight commented in it being a sweet plane as I'm getting back into IFR currency after a couple of busy years.

[hammdo]

With my C, the Carb temp in my engine monitor is wonderful. I have yet to use carb heat on landings (it’s part of my pre landing check list) as the temps have been well above freezing. I still always ck just to be sure. Starts are great too - but I also have a SureFly mag ;o)

I've flown a fuel injected F and yes, hot starts happen but, the hot restart technique works very well. Running lean of peak is much more aligned with fuel injection. Can’t go wrong with either choice - the extra 20 hp does makes a difference with DA in the summer...

-Don

[Jim Peace]

I have the carb temp on my JPI900...it should be standard....worth the extra money.

When we do the 200 dollar hamburger in my friends FI J there are always starting issues after lunch.  My carb C always starts.  Especially with a sky tech starter and a concord.  

[Mooneymite]

My O-360 consistantly starts within just a couple of blades and settles into a nice idle.   However, the FI engines' hot starts, even if successful and skillfully done always seem to grind away on the starter and usually starts initially at a higher RPM.  When it comes to engine starts, hot, or cold, the O-360 just seems "better".   

[hmasing]

18 hours ago, RobertGary1 said:

Worst case I can just flood the engine and then do a flood start.

That's my 100% go-to if the engine is even a little warm.

1. Mixture full rich
2. Fuel pump on for 5-10 seconds
3. Mixture full lean
4. Throttle to full
5. Start
6. As soon as the engine catches, push mixture to rich, pull throttle

Works every time.

[Ragsf15e]

1 hour ago, hmasing said:

That's my 100% go-to if the engine is even a little warm.

1. Mixture full rich
2. Fuel pump on for 5-10 seconds
3. Mixture full lean
4. Throttle to full
5. Start
6. As soon as the engine catches, push mixture to rich, pull throttle

Works every time.

I agree that it works, but you might consider trying the standard hot start first.  I certainly use the flooded start technique if my hot start were to fail (which is pretty rare), but I don’t like all the extra fuel, especially on purpose.  Might want to consider an increased risk of tailpipe fire.  If normal hot start fails, move to flooded start.

If you just leave everything like it was at shutdown, don’t prime, and crank, mine will fire on about the 3rd blade.  Then it’s just increase the mixture and it’s started.  If yours has trouble, maybe your SOS is weak?