IO360 Start Procedure

[flyboy0681]

It normally takes me about 6 or 7 seconds of cranking to start the '83 J. I use a checklist religiously and push the mixture in, prime, and then pull the mixture out - as described in the POH.

Today I was distracted while starting and left the mixture in and the engine turned over on the first crank, which took me by surprise.

While I don't plan on doing it again, what is the actual reason for leaning the mixture after the prime cycle? If she turned over immediately like today it would save a lot of wear and tear on the starter.

[aerobat95]

For my plane IO-360 A1A my start procedure is Mix Rich, Prop Full Foward, Master ON, Fuel Pump ON, Then throttle foward and back x3, Fule Pump OFF, starter engage. Typically starts in one or two blades.

[carusoam]

Ray,

Similar for the IO-550, but no throttle pumping.

Mixture out to start? If that's coming out of the POH, I would want to better understand why.

There is a hot start procedure for the IO-550 that begins that way. With talent it works, without talent, not so much. Back to the regular start procedure is next either way...

Best regards,

-a-

[jetdriven]

Why do you pump the throttle on a fuel-injected engine?

[aerobat95]

To be honest I am not really sure.....that was the technique that I was shown and it worked.

[gregwatts]

I have an 81 J.....mixture in.......fuel pump on until pressure shows on guage ( 3 seconds) throttle 1/4" in and starts right up.

[PilotDerek]

After I prime I wait a few seconds. I let the fuel evaporate a bit. I find that if I do that it starts right up (1-3 blade rotations).

[garytex]

Flyboy:

On mine, an IO 360 A, but with the same RSA fuel injector, if I leave the boost pump on and the mixture rich, the boost pump would flood the engine 2 seconds after the fuel pressure peaks. I think thats why the procedure is to close the mixture, to keep the boost pump from flooding the engine. So I prime till the pressure peaks, plus a second if OAT is cool, 2 seconds if chilly, and immediately shut off the boost pump. Mixture still rich, but boost pump off. Throttle set to approximate 1200 rpm when the engine fires. Then crank, starts right up.

Gary

[jetdriven]

To be honest I am not really sure.....that was the technique that I was shown and it worked.

I've never heard of throttle pumping to start on a fuel injected engine. On a carbureted engine, the accelerator pump squirts fuel into the intake, but a FI engine does not do that.

[bd32322]

It normally takes me about 6 or 7 seconds of cranking to start the '83 J. I use a checklist religiously and push the mixture in, prime, and then pull the mixture out - as described in the POH.

Today I was distracted while starting and left the mixture in and the engine turned over on the first crank, which took me by surprise.

While I don't plan on doing it again, what is the actual reason for leaning the mixture after the prime cycle? If she turned over immediately like today it would save a lot of wear and tear on the starter.

The reason is that if you actually prime for 3 seconds or whatever your POH mentions - you should create an over rich condition in the engine. This mixture is usually too rich to burn - depends on how long you primed for. So the next step is to get the mixture in the cylinders from an over rich condition to the right fuel air ratio so that the engine fires. The way that is done is to put the mixture at idle cut off and crank the engine - as the engine vents some of the over rich mixture through the exhaust - more fresh air comes in and the mixture becomes progressively leaner until its at the correct ratio for combustion. And then you need to push in the mixture again to provide fuel for sustained combustion.

Maybe you are over-priming? You might want to prime for 1 second less or until fuel flow shows a stable flow indication. Or you might try what others have mentioned - that you wait x number of seconds after you prime before you start cranking to promote the fuel to vaporize better.

As for your case today where you left the mixture in - I am not sure how that happened unless you forgot to prime aor didnt prime long enough and left the mixture in. That would also achieve the correct fuel air ratio by starting from an over lean condition (all air - no fuel) to more and more fuel per crank until it catches.

I am not exactly sure why we have to go from a over rich condition to an over lean condition to start - we could start the other way too - go from over lean to rich.

[aaronk25]

If engine is cold ( and of course depends how cold) on a fuel injected engine, mixture rich ( assuming the fuel pressure gauge reads 0) then push fuel boost switch for however long you desire to prime (2 sec) shut off fuel boost pump, wait a few seconds or until fuel pressure goes back to 0 and turn key to start. If your cranking and it doesn't start within a few seconds push the boost pump switch to put more fuel in and it will start. When cranking with the mixture forward the mechanical pump is delivering fuel but not enough to create a richer condition necessary for starting the engine that's why as your cranking if you need to add more fuel just turn the boost pump on. This way you only engage the starter once.

If you flood it idle cut off on the mix until it starts and next time don't hit the boost switch as long.

[Lood]

My procedure is about the same. For a normal start (cold):

Mixture fully rich, throttle wide open, prime with pump only until the fuel flow needle starts to move, pump off, throttle back to about 1200 rpm and I've found that my IO360 actually starts quicker when I pull the mixture back from fully rich, about one third. I suspect that this might have something to do with my home base altitude of 4000'.

Engine always start at or before the third blade.

[FloridaMan]

I have the SlickStart system on mine. I tend to hold the starter in while I advance the mixture, even after it tries to kick over. From my understanding, the SlickStart showers the cylinder with sparks instead of timed ignition while the starter is engaged, so I like to keep it coming until I'm sure it's starting. On other airplanes, I'll let off the starter on the first cylinder firing and see if it "catches," but I've found that on mine if I let off at that point, I'll often have to go through my start procedure again. With the exception of when I lost the left mag, the plane has never given any trouble starting (hot, cold, whatever).

[FlyDave]

I have an '82J and on cold starts I push everything forward and prime for between 2 and 5 seconds depending on OAT. When it's hot outside I find that I need to prime less and it's easy to over-prime and flood the engine. I'm not sure if my engine is more or less sensitive to this than others but that's what I've found. If done correctly it starts in 1-2 blades - consistently.

[flyboy0681]

It appears that everyone has their own flavor of starting procedure and whatever works best for the individual engine is probably the right way to go as long as it doesn't place any undue stress on any individual component.

[smccray]

It normally takes me about 6 or 7 seconds of cranking to start the '83 J. I use a checklist religiously and push the mixture in, prime, and then pull the mixture out - as described in the POH.

Today I was distracted while starting and left the mixture in and the engine turned over on the first crank, which took me by surprise.

While I don't plan on doing it again, what is the actual reason for leaning the mixture after the prime cycle? If she turned over immediately like today it would save a lot of wear and tear on the starter.

What is the state of your ignition system? My engine doesn't always start in 2 or 3 blades, but after IRANing the mags and replacing the leads, the engine starts much better than it did before the ignition system work.

[aaronk25]

If you have a fuel injected engine pushing the throttle wide open while priming doesn't do anything as said before and for those of you with carb engines pumping the gas with out cranking the engine will run fuel down the carb into the faring and if or more properly put "when" it backfires you will have a fire!!!! Only pump throttle on carb engines after you started cranking to create a updraft remember the carb is on the bottom and fuel will run down it in the absence of cranking.

Only time wide open is needed is when the engine is flooded, and your trying to get as much air in the engine as possible to clear some of the fuel that's puddled in the cylinders creating a over rich condition.

[Rustler]

Here's what the POH says.

http://www.deltaaviationllc.com/Nav%20Page/POH/M20J%20POH3203B.pdf

While this might not be specific to a particular "J" model, this is what my POH says, as well.

[flyboy0681]

Here's what the POH says.

http://www.deltaavia...0J POH3203B.pdf

While this might not be specific to a particular "J" model, this is what my POH says, as well.

It's not the same edition as mine, but the text is the same - Mixture to cutoff.

[carusoam]

Just checked an Ovation's POH to be sure as well. Thanks for sharing the J's POH.

C,J, and R. All different start procedures during normal start...

I see 100 (green) octane fuel is acceptable for this J as well. No issue in the event that 100LL becomes unavailable?

Best regards,

-a-

[danb35]

C,J, and R. All different start procedures during normal start...

No surprise, really; the three have very different fuel systems. I don't think any Mooney will be OK with <100 octane fuel, though.

[1964-M20E]

I have the SlickStart system on mine. I tend to hold the starter in while I advance the mixture, even after it tries to kick over. From my understanding, the SlickStart showers the cylinder with sparks instead of timed ignition while the starter is engaged, so I like to keep it coming until I'm sure it's starting. On other airplanes, I'll let off the starter on the first cylinder firing and see if it "catches," but I've found that on mine if I let off at that point, I'll often have to go through my start procedure again. With the exception of when I lost the left mag, the plane has never given any trouble starting (hot, cold, whatever).

When using this or the shower of sparks which I assume are very similar the regular points on the left mag are disconnected and the points on the right mag are disconenceted as well. The shower of sparks is then controlled by a retard set of points on the left mag. This allow the engine to start easier with a less advanced timing from the 20 or 25 degers BTDC normal timing. I was told that when the engine begins to catch hold the shower of sparks in to aloow the eingie to fully start. This will help prevent the dreaded kick back.

[DaV8or]

Today I was distracted while starting and left the mixture in and the engine turned over on the first crank, which took me by surprise.

While I don't plan on doing it again, what is the actual reason for leaning the mixture after the prime cycle? If she turned over immediately like today it would save a lot of wear and tear on the starter.

You don't do that all the time because as long as the mixture is not at full cut off, it is squirting fuel into the manifolds. If you wait too long to start cranking, your engine is quickly flooded and there is little hope of starting it then. Also fuel can get down into the exhaust and ignite when you do start and cause serious damage to the exhaust system.

Here's what I do hot, or cold. When I shut down the engine I run it up to 1400 rpm and then cut the mixture. Then I never, ever touch the throttle again until the next start. On a cold start, I'll prime the engine by getting the system pressurized with the boost pump, then go full rich for 7 seconds. This is the right amount of time for my engine, yours may vary, so you'll have to experiment. After the 7 seconds, I pull the mixture closed again and then start cranking. As it starts to take, I go full rich. Usually on the 3rd blade.

On a hot start, I do the same, except no priming. Just get in, get the fuel system pressurized with the boost pump and start cranking. Always fires right up.

[Lood]

I've also read and actually seen the start procedure with the mixture in idle cut off. I tried it a couple of times, but then my engine takes forever before it starts.

[bd32322]

On a hot start, I do the same, except no priming. Just get in, get the fuel system pressurized with the boost pump and start cranking. Always fires right up.

Just to be clear - you mean on a hot start you have the mixture at idle cut off and then you use the boost pump to pressurize the fuel system. I heard thats how the continentals like it - wasnt sure about the lycons

For me it just starts at idle cut off on a hot start. One thing that helps is to open the oil door on the cowl after landing to let the engine cool better - maybe it vaporizes the fuel in the pipes less ... I got that from someone's post on this forum - dunno who - but it seems like a good idea and I do it. Also park it facing the wind if anticipating a hot start .. etc etc