I have a new to me io520, I have been trying to figure out how to hot start it and keeping the rpm's low to not suck up gravel. I tried flooding it a few times and it works, but I do know to be careful with the backfiring and keeping it cranking if it does. I tried full throttle and ICO but I noticed a few gph registering on the meter and stopped, wasn't sure if it was letting fuel into the engine or not.

I tried full throttle and full mix and the boost pump for a second and cranking while backing the throttle off and that seems to work sometimes, otherwise I just let it sit 15+ minutes and start it like I would cold. Seems more like voodoo then going by the book.

alaskan9974 wrote:I tried full throttle and full mix and the boost pump for a second and cranking while backing the throttle off and that seems to work sometimes

Use this method except slowly open the throttle from idle rather than going the other way. Be ready once it starts running sometimes they need another shot of boost after they've run a half second. Keeping the RPM low on a hot start is going to be a challenge but will just take being familiar with it. Be quick with the throttle. I use several different C-188's during the summer equipped with the IO-520D and some variation of this method works on all of them. Granted, I'm not as concerned about picking up gravel on start up. Well, I am but I start up on pavement in a tail dragger.

alaskan9974 wrote:...I tried full throttle and full mix and the boost pump for a second and cranking while backing the throttle off...

High DA altitudes is a different story, but for Alaska and for normal airport altitudes and temperatures you are doing the right thing, only run the boost pump as long as you would for a cold start. For me generally that's until I see 10-14 GPH (more than a second for sure). Then crank with mixture full rich and from full throttle walk the throttle out. You'll be coming from an over-rich condition so as the engine catches it will be stumbling just a bit- keep walking it back which will allow you to start it without the engine racing. Works all the time unless at high DA in which case the mixture will need to be way out.

Go from closed throttle to open and you'll be going the wrong way when it catches and probably race the engine before you can walk it back to idle.

Works on IO520's and IO550's.

I agree with lost. Brian Schanche let me start his 185 on floats at the dock in Florida. He was standing on the dock and said he didn't want a big blast when it started. Hit the boost for a second, throttle cracked a little, start cranking and slowly pushing throttle. It started----no big blast and didn't have to add any more boost. I've done the throttle wide open and pulling in another 185 too

I use the following for io550's and io520's at work, including one bastard child that is a 520 converted to a 550 with a turbo thrown in the mix.

Cold start:
Everything full forward, boost pump 5 seconds. Reduce throttle to 1/4, crank, fires instantly. < The easiest

Hot start:
Everything full forward, boost pump for less than a second, only enough to here the whine of it steady out. Throttle to idle, crank. If it doesn't fire in 1-2 blades, throttle full forward and it'll fire 100% of the time in 3-4 more blades. As soon as it catches, throttle back to a low RPM. Obviously if you're a slow mover the RPM's get up high with the full throttle in, but I've never had that be a problem since my hand is always on the throttle. Doesn't suck gravel unless you're slow to reduce.

No idea if this is technically correct, but it has never failed me (yet) on a few different engines.

With my MT prop, I generally try to avoid start situations with my throttle anywhere above high idle since it revs to whatever rpm the throttle setting matches when it lights...like right now. Flooded start procedures are a setup for having to move the throttle position to a more open (even if you are moving it back from full open) and producing this high rpm start.

Instead, I use the continental engine hot start procedure as described in their engine manual.

* Mixture lean (very important)
* Fuel pump on
* Throttle to full open
* Wait about 20 seconds in this configuration
* Fuel pump off
* Mixture rich
* Depending on the setup of your engine, either no prime or a very brief prime with the fuel pump.
* Throttle to normal start position
* Start

If anyone tries this procedure, please report back with your results.

I prefer this method as it avoids the potential for the high rpm start, especially with the MT.

Pat your head , rub your belly , mixture all the way out . Rub your head , pat your belly mixture full rich . Full throttle , no throttle . Crank it , yell come on mother@&$”&@. Works every time .

TSIO520R on 81' T210: John Frank Cessna Pilots Asso. hot start. Mixture- idle cut-off; throttle full; boost pump on for 2 minutes. Purges hot fuel back to tank. Switch to other fuel tank and do normal cold start.

OR

What I did after doing the above for several years: had Cessna shop install over-size battery cables and spins engine fast enough bubbles in the fuel lines pass right on through and starts every time.

Jack

I’m following this discussion with interest. Continental constant flow fuel injection is fairly similar across their engines so I might learn something that will help me start my Conti IO-360 if I’m ever in a pickle.

When we first started flying it was a pain to hot start it, sometimes nearly draining both PC680s. After carefully adjusting the injection IAW the TCM appropriate service bulletin it now starts easy peasy.

Hot start: mixture full rich, throttle cracked, crank. Pretty much always starts but if it doesn’t start after a couple blades then I hit the boost pump for a second while cranking and it immediately fires.

If I don't know the engine, I set the throttle at 1/4.. boost pump for 1-2 sec then off..
Mixture full lean.
Crank, and slowly and smoothly advance the mixture until it fires, let go, then continue to full rich, and reduce throttle..

If it doesn't fire, pull the mixture, cycle the boost pump, try again.. all while cranking.. if it fires, let go the key immediately to get the second mag in the loop.

thats what I was taught.. YMMV.. I am not very experienced by any means, but it works..

dave

FW Dave wrote:If I don't know the engine, I set the throttle at 1/4.. boost pump for 1-2 sec then off..
Mixture full lean.
Crank, and slowly and smoothly advance the mixture until it fires, let go, then continue to full rich, and reduce throttle..

If it doesn't fire, pull the mixture, cycle the boost pump, try again.. all while cranking.. if it fires, let go the key immediately to get the second mag in the loop.

thats what I was taught.. YMMV.. I am not very experienced by any means, but it works..

dave

This kinda sounds like the start procedure for an injected Lycoming. I haven't run into many continental operators hot starting this way.

Wow, I guess I was doing it all wrong all those years and thousands of starts.....

Shit, I always just followed the start procedures presented in the POH. Never had a problem starting, including on floats at temps over 100 degrees and seven or eight starts a day.

MTV

mtv wrote:Wow, I guess I was doing it all wrong all those years and thousands of starts.....

MTV

Me too. I'm not the most experienced knuckle head here but I have a few hours in 207s and 206s. My memory is good, even if short, and I don't recall ever starting anything with the throttle wide open.

Nice to see changed your avatar Keith. Starting to piss all the 170 guys off since you jumped ship!

The following works for me in my 185. Numerous hot starts daily. Mixture ICO, throttle - full, run boost pump for 5 seconds, mixture full rich, throttle slightly open, starts perfectly every time.

Running the boost pump with the Mixture at ICO purges the hot fuel from the distribution lines (leading to vapour lock) and introduces ambient temperature fuel. Lots of ways to get them started but this has always worked well for me.

Squash wrote:With my MT prop, I generally try to avoid start situations with my throttle anywhere above high idle since it revs to whatever rpm the throttle setting matches when it lights...like right now. Flooded start procedures are a setup for having to move the throttle position to a more open (even if you are moving it back from full open) and producing this high rpm start.

Instead, I use the continental engine hot start procedure as described in their engine manual.

http://www.insightavionics.com/pdf%20files/Continental.pdf

If anyone is interested in where I received this information or the rationale behind the procedure, I have included the referenced engine handbook. The hot start section begins on page 32. I started using this procedure after my MT prop was installed. Prior to the lightweight propeller, my black mac could handle the standard hot start procedure as described in my POH, but those procedures with the throttle open don't work as well for me and the MT.

I also use the Continental procedures (Full throttle, Mixture cut off, pump on). I do not fly in the hottest place, so often only use the fuel pump for 10-20 seconds instead of the 30 (?) recommended. I tend to start the pump then fasten my seat belt and close the door. The IO520 I fly behind now stumbles a bit on hot starts and sometimes dies, but having the pump on very briefly as I start seems to make it happy.