IO-540 starting technique

akloon · Post by **akloon** » Fri Jul 06, 2007 11:26 pm

I traded up to an M7 from an M5 and got an IO-540. I have followed the POM techniques and a few others and I'm still not finding a consistent way to start this thing. Hot starts are worse, of course, since I can't tell if it's vapor locked or just starved. Then, it floods easily and I'm down to half battery and guessing. Any consistent techniques or other ROT would be welcome!

Lowflybye · Post by **Lowflybye** » Sat Jul 07, 2007 5:16 am

For Hot Starts or flooded engine

- Mixture off
- Throttle Full
- Boost Pump ON for 30-60 seconds (this will purge the fuel system)
- Continue on to Normal Startup procedures

Normal Starts...this will not allow the engine to flood

- Mixture Full
- Throttle 1/2 inch
- Boost pump ON until positive fuel pressure is achieved (about 5-8 seconds)
- Boost Pump OFF
- Mixture OFF
- START
- Advance Mixture to Full on first "fire" of a piston

This startup procedure worked flawlessly on our Cessna 210 (IO-520) for years and I have started our 0-360 the same way. I have been able to start aircraft that were flooded using this technique, much to the surprise fo the owners. I am sure that there are other techniques out there that will work as well, but this is "old faithful" for me.

akloon · Post by **akloon** » Sat Jul 07, 2007 9:30 am

The second procedure is pretty much out of the book, but has still been inconsistent for me. The flooding procedure is similar to what I do as well, although it doesn't take 30-60 seconds for me to purge/flood the engine, more like about 15. I'll end up flooding it on purpose, just so I know there's fuel in there, then open the throttle, mixture full lean, and crank. If it doesn't fire right off I'll simply wait for a few minutes and try it again. Sooner or later the cylinder dries out to whatever perfect combination it needs. I have to be quick with the mixture in and throttle idle in this scenario, obviously.

Green Hornet · Post by **Green Hornet** » Sun Jul 08, 2007 3:34 pm

The first procedure works for my hot start exxcept I don't use full throttle. You may have to give the throttle a little more than 1/2 inch and you do have to be quick with the mixture. Once she kicks in you can bring the throttle back. I got this from a crop duster who told me Lycoming 540 IO need to be starved for hot starts but it is important to give it a little more throttle than 1/2 ince but not full. After a while you get a sense for how much. It appears to be relative to the engine.
My normal start differs in that I leave the mixture full on cold start and lean after start.

210TC · Post by **210TC** » Sun Jul 08, 2007 7:25 pm

Akloon,
Would you post sum pictures of your airplane so we can see the paint job.
Thanks

210TC · Post by **210TC** » Sun Jul 08, 2007 7:41 pm

Make sure that left mag is in GOOD shape. THIS IS A BIG ONE
If I go to full mixture when she fires (real hot) she will flood and shut down.
Crack throttle
boost on
after rotation starts
ease in mixture (mark where it fire's) hold and advance mixture slowly.

2nd proceedure
Close throttle
boost on 10 seconds then off.
mixture full rich
throttle cracked
crank
hit boost when she fires (just for a second or two)

maules.com · Post by **maules.com** » Sun Jul 08, 2007 9:06 pm

Only one of the magnetos is fitted with an impulse, so for much improved starting the other mag can be fitted with an impulse also which prolongs the spark front.

210TC · Post by **210TC** » Mon Jul 09, 2007 4:21 pm

As Jeremy stated: you have one mag with impulse coupler, this is the left mag and hard starting can frequently be HELPED by keeping this jewel in top condition OR you can add an impulse coupler to the right mag, giving double fire for start up (not many people do this, nor the factory).
For those of you that would like to know, an impulse coupler forces the mag to SNAP, accelerating the RPM of the mag to generate more electrical current during start-up. Kind of like a wind-up toy.
I have had BAD starting problems with normal mag drop after engine started, but the left mag was the problem, so don't be fooled, CHECK IT OUT. Points are cheap, the condenser is $80.00. I just had this problem on a trip to California. Keep your plugs gaped at minumin clearance, this requires less voltage to fire the plug.

210TC · Post by **210TC** » Mon Jul 09, 2007 6:01 pm

Almost forgot,
If you install an impulse coupler on the right mag you will need to replace the ignition switch.
The ignition switch during start up (sping loaded portion) grounds out or turns the right mag off until you let up on the switch when she fires.

akloon · Post by **akloon** » Mon Jul 09, 2007 8:23 pm

I can't for the life of me understand why you'd continue boosting fuel into a flooded engine. Can you explain why your last two procedures work?
I'm getting a very good (low) drop between mags on that check, but I'll be annually soon and check that and the plug gaps. Thanks!
Dave

210TC · Post by **210TC** » Mon Jul 09, 2007 9:17 pm

I fly in very hot conditions and just added my procedure's for hot start. So I don't flood.
When I,m flooded (only happened two or three times)I position the throttle wide open and I set for a few minutes, then crank without any mixture or boost (wide open throttle). The lower plugs will be wet enough to get it started and I hit the boost, but I don't add mixture until she starts to clear the black smoke. Gotta be qwik with your hands.
Hope that makes sense.

Still would like to see pictures of your bird.

Jet-A · Post by **Jet-A** » Mon Jul 16, 2007 3:35 pm

HOT START:
Throttle: 2 full turns in (about 1/4" open).
Mixture: Idle cut-off - DO NOT BOOST.
Starter engaged
Upon first fire, increase mixture.

Typically, my blade swings through about 2 revolutions or less to "catch fire"... The hotter the engine on start, the faster she starts. I.E. flying into the airport for fuel and then starting up again to taxi to a tie-down or something. Very easy to start.

COLD START:
This one varies slightly on the OAT, but it's exactly what the book calls for, which has been previously stated. I usually wait for the fuel flow meter to move and then count to 3 and turn off the boost pump. The colder it is outside, the more I keep the boost pump on (about one extra second or so).

Flyin'Dutch' · Post by **Flyin'Dutch'** » Tue Oct 16, 2007 5:38 pm

akloon wrote:I traded up to an M7 from an M5

You may want to consider rewriting that statement!

a64pilot · Post by **a64pilot** » Wed Oct 17, 2007 4:07 am

I cleaned my plugs and gapped them at the min. That helped a lot, so I knew I was on to something. Fine wires pretty much cured the hot start issue. I had been chasing my tail thinking fuel, while David had been right all along. Mine was weak ignition, but with a freshly re-built single drive mag, I didn't have many options there. Try www.plugguy.com for fine wires. They are not inexpensive!

ChuckAldrian · Post by **ChuckAldrian** » Wed Oct 17, 2007 6:41 pm

I have a 2000 M7 IO-540/260HP that had nothing but problems in starting from day one, hot or cold. Put in a Slick-Start system for about $500 and have the best starting engine I have ever had in 42 years of flying. Hot or cold it fires up pronto!! If I remember right, it increases voltage to the plugs by 300% and rather than one spark at detonation time, it's a shower of sparks. Love Slick-Start. Remember this is made by the same company that made YOUR magnetos on a IO-540!! So I think they know what they are doing.

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