HOT START PROCEDURE

[Danb]

I’m having a time with my hot start procedure or lack of. My bravo had no issues with hot starts especially after electronic mag.

D

[M20TN_Driver]

Not sure what the Bravo procedure is. On my acclaim I run high boost for a while with the throttle and mixture filly closed then go to the cold start procedure and it will fire right up. Good luck. 

[Danb]

Thanks, bravo hot start was procedure similar to regular start procedure 

[Fly Boomer]

1 hour ago, Danb said:

I’m having a time with my hot start procedure or lack of. My bravo had no issues with hot starts especially after electronic mag.

D

As M20TN_Driver suggests, I suspect the best success will come by taking advantage of the TCM "recirculating fuel" system.  With the mixture at idle cutoff, running the boost pump recirculates cool(er) fuel through parts of the system in which the fuel has likely vaporized sitting right above the engine.  At idle cutoff, no fuel is being delivered to the cylinders.  I have read that 30 seconds is not an unreasonable amount of time to run the boost pump at idle cutoff.  At that point, I would be tempted to try a start without priming at all.  If nothing happens in a revolution or two, give it a little bit of prime and try again.  I think it was Mike Busch who said "If it won't start in the summer, you have probably flooded it." and "If it won't start in the winter, you probably need more prime."  Mike flies behind a pair of TSIO-520s with a very similar fuel system.

[NewMoon]

On 9/19/2023 at 4:16 PM, Danb said:

I’m having a time with my hot start procedure or lack of. My bravo had no issues with hot starts especially after electronic mag.

D

Contact Brian Kendrick, he has a very fool proof system that has served many well.

[jlunseth]

I have a 231 which is a Conti engine. I read all the material it appears you all have read about hot starts. I found that the procedure of closing the MP and fuel flow and running the pump for an extended period was actually dangerous, although it is recommended by some very authoritative sources. It is the one way I can get my 231 to backfire on start up. The first time or two that I tried it, a couple of instructors happened to be walking by and they said afterward that fuel was dumping out under the aircraft. So I have modified the procedure a little.

The typical problem is that the engine will catch (fire) but not continue to run. The reason is that there is air in the lines and the problem is to get rid of the air before starting so the engine receives a constant fuel flow. Otherwise it will run on the primer fuel until that is exhausted and then quit. My aircraft high boost has a safety cage over it. If I leave the safety cage in place and just push the top left corner of the high boost switch, the switch acts as an instant-off switch. I also have an excellent engine monitor in the JPI930. So what I do, before attempting to start, is to close the MP and fuel flow and then push the top left corner of the switch to run the high boost and watch the fuel pressure on the JPI. It will run up from some low number to something in the sixteens or 17’s and then stabilize (you can keep holding the switch down but the fuel pressure does not increase). I don’t care what the pressure is, I just care that it stabilizes, which indicates full fuel lines. As soon as I reach stable fuel pressure I let go of the switch, and being in instant on mode it stops pumping. I then put the fuel flow in full rich, the MP full in, and push the primer switch for whatever time is specified for the day OAT in the POH. This dumps primer fuel directly into the cylinder. I then put the MP in the start position (partiallly in), leave the fuel flow at full rich, and hit the ignition switch.

This system never fails in my engine. It will start everywhere, in all conditions, even at Leadville in the middle of the summer (which I have done) or in the Minnesota cold (which I have also done many times). The only caveat is that I won’t try it at under 20 dF. In a pinch it would work but it would be really hard on the engine. Better to find a way to warm the engine.

Sounds complicated, but what I am doing is simple. I am first filling the fuel lines, which have drained down and have air in them. Then I prime the engine normally. Then start. If the engine still fires but dies, I will just push the top left corner of the high boost in instant on mode as soon as the engine fires, which supplies good fuel flow to the engine, and it always starts, letting go of the instant on switch as soon as the engine is happy.  

Don’t know how this would work in a Lyc or a more modern Conti, but it works all the time, every time, everywhere, in my TSIO-360-LB.

Once upon a time I flew to Leadville with Wayne Fisher during a Mooney PPP. He has sent an email in advance that everyone was to study and know the high hot start procedure if they wanted to land at Leadville, so I did. That procedure was an utter failure. But before I ran the battery down I reverted to my standard procedure and it worked like a charm.

[Fly Boomer]

10 minutes ago, jlunseth said:

I have a 231 which is a Conti engine. I read all the material it appears you all have read about hot starts. I found that the procedure of closing the MP and fuel flow and running the pump for an extended period was actually dangerous, although it is recommended by some very authoritative sources. It is the one way I can get my 231 to backfire on start up. The first time or two that I tried it, a couple of instructors happened to be walking by and they said afterward that fuel was dumping out under the aircraft. So I have modified the procedure a little.

The typical problem is that the engine will catch (fire) but not continue to run. The reason is that there is air in the lines and the problem is to get rid of the air before starting so the engine receives a constant fuel flow. Otherwise it will run on the primer fuel until that is exhausted and then quit. My aircraft high boost has a safety cage over it. If I leave the safety cage in place and just push the top left corner of the high boost switch, the switch acts as an instant-off switch. I also have an excellent engine monitor in the JPI930. So what I do, before attempting to start, is to close the MP and fuel flow and then push the top left corner of the switch to run the high boost and watch the fuel pressure on the JPI. It will run up from some low number to something in the sixteens or 17’s and then stabilize (you can keep holding the switch down but the fuel pressure does not increase). I don’t care what the pressure is, I just care that it stabilizes, which indicates full fuel lines. As soon as I reach stable fuel pressure I let go of the switch, and being in instant on mode it stops pumping. I then put the fuel flow in full rich, the MP full in, and push the primer switch for whatever time is specified for the day OAT in the POH. This dumps primer fuel directly into the cylinder. I then put the MP in the start position (partiallly in), leave the fuel flow at full rich, and hit the ignition switch.

This system never fails in my engine. It will start everywhere, in all conditions, even at Leadville in the middle of the summer (which I have done) or in the Minnesota cold (which I have also done many times). The only caveat is that I won’t try it at under 20 dF. In a pinch it would work but it would be really hard on the engine. Better to find a way to warm the engine.

Sounds complicated, but what I am doing is simple. I am first filling the fuel lines, which have drained down and have air in them. Then I prime the engine normally. Then start. If the engine still fires but dies, I will just push the top left corner of the high boost in instant on mode as soon as the engine fires, which supplies good fuel flow to the engine, and it always starts, letting go of the instant on switch as soon as the engine is happy.  

Don’t know how this would work in a Lyc or a more modern Conti, but it works all the time, every time, everywhere, in my TSIO-360-LB.

Once upon a time I flew to Leadville with Wayne Fisher during a Mooney PPP. He has sent an email in advance that everyone was to study and know the high hot start procedure if they wanted to land at Leadville, so I did. That procedure was an utter failure. But before I ran the battery down I reverted to my standard procedure and it worked like a charm.

Sounds like pulling mixture to idle cutoff isn't cutting off fuel?

[Shadrach]

15 minutes ago, jlunseth said:

I have a 231 which is a Conti engine. I read all the material it appears you all have read about hot starts. I found that the procedure of closing the MP and fuel flow and running the pump for an extended period was actually dangerous, although it is recommended by some very authoritative sources. It is the one way I can get my 231 to backfire on start up. The first time or two that I tried it, a couple of instructors happened to be walking by and they said afterward that fuel was dumping out under the aircraft. So I have modified the procedure a little.

The typical problem is that the engine will catch (fire) but not continue to run. The reason is that there is air in the lines and the problem is to get rid of the air before starting so the engine receives a constant fuel flow. Otherwise it will run on the primer fuel until that is exhausted and then quit. My aircraft high boost has a safety cage over it. If I leave the safety cage in place and just push the top left corner of the high boost switch, the switch acts as an instant-off switch. I also have an excellent engine monitor in the JPI930. So what I do, before attempting to start, is to close the MP and fuel flow and then push the top left corner of the switch to run the high boost and watch the fuel pressure on the JPI. It will run up from some low number to something in the sixteens or 17’s and then stabilize (you can keep holding the switch down but the fuel pressure does not increase). I don’t care what the pressure is, I just care that it stabilizes, which indicates full fuel lines. As soon as I reach stable fuel pressure I let go of the switch, and being in instant on mode it stops pumping. I then put the fuel flow in full rich, the MP full in, and push the primer switch for whatever time is specified for the day OAT in the POH. This dumps primer fuel directly into the cylinder. I then put the MP in the start position (partiallly in), leave the fuel flow at full rich, and hit the ignition switch.

This system never fails in my engine. It will start everywhere, in all conditions, even at Leadville in the middle of the summer (which I have done) or in the Minnesota cold (which I have also done many times). The only caveat is that I won’t try it at under 20 dF. In a pinch it would work but it would be really hard on the engine. Better to find a way to warm the engine.

Sounds complicated, but what I am doing is simple. I am first filling the fuel lines, which have drained down and have air in them. Then I prime the engine normally. Then start. If the engine still fires but dies, I will just push the top left corner of the high boost in instant on mode as soon as the engine fires, which supplies good fuel flow to the engine, and it always starts, letting go of the instant on switch as soon as the engine is happy.  

Don’t know how this would work in a Lyc or a more modern Conti, but it works all the time, every time, everywhere, in my TSIO-360-LB.

Once upon a time I flew to Leadville with Wayne Fisher during a Mooney PPP. He has sent an email in advance that everyone was to study and know the high hot start procedure if they wanted to land at Leadville, so I did. That procedure was an utter failure. But before I ran the battery down I reverted to my standard procedure and it worked like a charm.

I will assume by “backfire” (combustion in the intake) you mean afterfire (combustion in the exhaust). At idle cut off, no fuel should flow beyond the servo. If running the pump at idle cutoff over-primes your engine, then fuel is making it through the cylinders and into the exhaust while at idle cutoff. I don’t think that is supposed to happen.

[Shadrach]

On 9/19/2023 at 5:45 PM, Fly Boomer said:

As M20TN_Driver suggests, I suspect the best success will come by taking advantage of the TCM "recirculating fuel" system.  With the mixture at idle cutoff, running the boost pump recirculates cool(er) fuel through parts of the system in which the fuel has likely vaporized sitting right above the engine.  

Idle cut off and return line are at the servo. The fuel divider and injector lines (top of the engine) will not see fresh fuel until mixture is moved from idle cut off position.

Running the pump with the mixture at ICO ensures that the coolest fuel available goes to the flow divider when the mixture is opened. It also helps carry heat away from the fuel system aft of the cut off valve.

[jlunseth]

It’s certainly possible that there was some kind of leak or other issue with the fuel system in my aircraft. As of yesterday I have a new engine with a new fuel system, so maybe that backfire issue will be gone. But here is the point I was making. From having started my engine a few thousand times I can say that running the fuel with the fuel flow closed for 30 seconds - or a full minute which is the recommendation Walter Atkinson made a few years ago - is just not necessary and can have adverse consequences. All that is necessary is to run the boost with the fuel flow closed until the fuel pressure stabilizes. Once it stabilizes the lines are full and you can then start the engine normally. If a little bump in fuel flow is needed (the engine fires but still does not stay running) just hit the boost pump for a little bit until it is running consistently. Works every time. Everywhere. Hot or cold. High or low. Might be different with NA engines, I don’t know, but sure works in my Conti TSIO.

[Shadrach]

1 minute ago, jlunseth said:

It’s certainly possible that there was some kind of leak or other issue with the fuel system in my aircraft. As of yesterday I have a new engine with a new fuel system, so maybe that backfire issue will be gone. But here is the point I was making. From having started my engine a few thousand times I can say that running the fuel with the fuel flow closed for 30 seconds - or a full minute which is the recommendation Walter Atkinson made a few years ago - is just not necessary and can have adverse consequences. All that is necessary is to run the boost with the fuel flow closed until the fuel pressure stabilizes. Once it stabilizes the lines are full and you can then start the engine normally. If a little bump in fuel flow is needed (the engine fires but still does not stay running) just hit the boost pump for a little bit until it is running consistently. Works every time. Everywhere. Hot or cold. High or low. Might be different with NA engines, I don’t know, but sure works in my Conti TSIO.

Is it actually backfiring (intake) or is it afterfiring (exhaust)?

[jlunseth]

22 minutes ago, Shadrach said:

Is it actually backfiring (intake) or is it afterfiring (exhaust)?

Don’t know. I am inside the aircraft at the time trying to start. It goes bang (or it used to, in the old engine). Thereafter, the engine does not like me very much (fires softly for a little bit once I get it started). I don’t like that so I don’t overcharge the engine with fuel for the sake of cooling the fuel system, which is not necessary. The charging system in the TSIO360 is constant flow through injectors into the intake manifold just outside each cylinder so it probably does not matter where it starts because an intake valve somewhere will always be open allowing combustion through the whole engine, or at least one side of it. Then it is not very happy. Not necessary to do that.

[Shadrach]

1 hour ago, jlunseth said:

Don’t know. I am inside the aircraft at the time trying to start. It goes bang (or it used to, in the old engine). Thereafter, the engine does not like me very much (fires softly for a little bit once I get it started). I don’t like that so I don’t overcharge the engine with fuel for the sake of cooling the fuel system, which is not necessary. The charging system in the TSIO360 is constant flow through injectors into the intake manifold just outside each cylinder so it probably does not matter where it starts because an intake valve somewhere will always be open allowing combustion through the whole engine, or at least one side of it. Then it is not very happy. Not necessary to do that.

All certified gasoline, injected, aviation engines are constant flow.
I have only seen a backfire occur once regarding an aircraft.  It was a Tripacer that had been over primed and it caused a dull pop followed by a fire that damaged the air box. You likely had some amount of excess fuel enter the exhaust and ignite just up stream of the turbine. Not ideal either. Bottom line is that boost pump at ICO should not deliver any fuel to the intake manifold.

[Pinecone]

1 hour ago, jlunseth said:

Don’t know. I am inside the aircraft at the time trying to start. It goes bang (or it used to, in the old engine). Thereafter, the engine does not like me very much (fires softly for a little bit once I get it started). I don’t like that so I don’t overcharge the engine with fuel for the sake of cooling the fuel system, which is not necessary. The charging system in the TSIO360 is constant flow through injectors into the intake manifold just outside each cylinder so it probably does not matter where it starts because an intake valve somewhere will always be open allowing combustion through the whole engine, or at least one side of it. Then it is not very happy. Not necessary to do that.

The point is, there is something wrong with your fuel system.

WIth the mixture pulled all the way out, NO FUEL should be going to the cylinders or into the intake.  If there is, your fuel system needs to be fixed.

All aircraft fuel injection systems are constant flow.  If the valve is closed when you prime, the fuel just sits in the intake until that valve opens when you crank. 

You do not seem to really know how these systems, and engines in general, work.

[LANCECASPER]

3 hours ago, Pinecone said:

The point is, there is something wrong with your fuel system.

WIth the mixture pulled all the way out, NO FUEL should be going to the cylinders or into the intake.  If there is, your fuel system needs to be fixed.

All aircraft fuel injection systems are constant flow.  If the valve is closed when you prime, the fuel just sits in the intake until that valve opens when you crank. 

You do not seem to really know how these systems, and engines in general, work.

I would definitely re-think your post.

Of all of the owners on Mooneyspace I would put @jlunseth in the top ten of knowing how his airplane and engine, and of all of the M20K 231 owners I would put him at the top of the list on the TSIO-360-GB and LB engines. I'm nowhere on either list even though I owned an '83 231 and a '97 Encore.

He may not be stating it in a way that you understand, but in following his posts since 2011 and looking back at the posts he's  made since 2009, he knows his airplane and his engine very well.

[Shadrach]

6 hours ago, LANCECASPER said:

I would definitely re-think your post.

Of all of the owners on Mooneyspace I would put @jlunseth in the top ten of knowing how his airplane and engine, and of all of the M20K 231 owners I would put him at the top of the list. I'm nowhere on either list even though I owned an '83 231 and a '97 Encore.

He may not be stating it in a way that you understand, but in following his posts since 2011 and looking back at the posts he's  made since 2009, he knows his airplane and his engine very well.

I enjoy John's posts as much as anyone and he definitely is a well of good Mooney information both general and K model specific. However, Pinecone is correct…No fuel should go beyond the servo at idle cut off.  Not understanding that is not a crime nor is it a personal attack to point it out. 

[LANCECASPER]

1 hour ago, Shadrach said:

I enjoy John's posts as much as anyone and he definitely is a well of good Mooney information both general and K model specific. However, Pinecone is correct. No fuel should go beyond the servo at idle cut off.  Not understanding that is not a crime nor is it a personal attack to point it out. 

I agree 100% with everything you said - we are all learning - that's why we are here. But the last statement made, that he doesn't know how engines in general work is completely false. 

[Shadrach]

27 minutes ago, LANCECASPER said:

I agree 100% with everything you said - we are all learning - that's why we are here. But the last statement made, that he doesn't know how engines in general work is completely false. 

Agreed. Unnecessary and not nicely worded. That being said, I doubt @jlunseth is going to lose any sleep over it. Given my own challenges with being tactful, I try not to let it bother me when others showcase their shortcomings in that department.

[jlunseth]

Hey folks, thanks, but I have to confess I am not putting alot of thought into this because as of Friday, I have an all new engine with an all new fuel system if no one caught that. It does not matter to me whether there was a problem with the old one or what the cause might have been. We did do some work on the fuel system over a period of years, including one complete rebuild when I first got the aircraft, and the installation of a new pump at one point, and the only effect that had was to shorten the time I had to run the fuel pump to get a stable fuel pressure. The only point I was trying to make was that filling the fuel lines is the first most important thing you can do to make any start work. Don't know what diagnosing my now-gone old engine has to do with this thread, which is about engine starts. Tried the old start technique on the new engine for the first time today. Worked great.

[Shadrach]

On 11/20/2023 at 5:34 PM, jlunseth said:

Hey folks, thanks, but I have to confess I am not putting alot of thought into this because as of Friday, I have an all new engine with an all new fuel system if no one caught that. It does not matter to me whether there was a problem with the old one or what the cause might have been. We did do some work on the fuel system over a period of years, including one complete rebuild when I first got the aircraft, and the installation of a new pump at one point, and the only effect that had was to shorten the time I had to run the fuel pump to get a stable fuel pressure. The only point I was trying to make was that filling the fuel lines is the first most important thing you can do to make any start work. Don't know what diagnosing my now-gone old engine has to do with this thread, which is about engine starts. Tried the old start technique on the new engine for the first time today. Worked great.

Congratulations on the new Powerplant. You definitely got your moneys worth out of the old one. Would be an interesting data point to see if the new one behaves the same. I think the only thing anyone was taking issue with was your suggestion that a well understood and frequently utilized Continental hot start procedure was a bad idea based on your anecdotal experience with your old power plant.

[Pinecone]

20 hours ago, LANCECASPER said:

I would definitely re-think your post.

Of all of the owners on Mooneyspace I would put @jlunseth in the top ten of knowing how his airplane and engine, and of all of the M20K 231 owners I would put him at the top of the list on the TSIO-360-GB and LB engines. I'm nowhere on either list even though I owned an '83 231 and a '97 Encore.

He may not be stating it in a way that you understand, but in following his posts since 2011 and looking back at the posts he's  made since 2009, he knows his airplane and his engine very well.

Thanks.

But he says his engine gets over primed when he runs the boost pump with the mixture full back.  That indicates that something is wrong.  There should be no fuel flow to the injectors with the mixute in ICO.

I agree with his point about filling the fuel lines, but only those fuel lines up to the point that the mixture control stops the fuel.

I do think some of the issue is the terms and how he puts things.  But his comment about fuel in that is let in an open valve during priming has anything to do with the other cylinders doesn't match any form of engine operation I know of.   It is possible that in a Lycoming that excess priming fuel can run down the intake and be sucked up by other cylinders, but hard to do on a Continental with the top mounted intake tubes.

[dkkim73]

Following this thread with great interest as a new Acclaim owner (plane still elsewhere). If you'll forgive a minor thread deviation ("Moon Flight, turn right 10 degrees, vectors for newbie"), what are some good references for understanding operational principles and best practices for the TSIO-550G, and similar powerplants? 

I started going through the intro portions of John Deakin's online engine course and will probably do the whole thing. So far it is focusing more on combustion theory, leaning, etc. 

Any advice appreciated. 

David

[mike_elliott]

David, Dan..

What I do that seems to work every time on hot starts

HEAT SOAKED:

Run low boost 1 min with mixture and MP at idle cutoff to cool fuel pump and possibly evac lines

HOT START

MP and mixture full in.

run Hi Boost until max fuel flow (about 3-4 sec)

Crank, slowly retarting MP towards idle. Stop retarding 1/2 way if not fired while continue to crank

 

By introducing a bit more than needed fuel and then allowing the air/fuel mixture to reach the happy point when cranking, you will "stumble" on the correct ratio to get it fired.

Continentals typically need fuel while lycs dont when hot.

 

[Danb]

I’ve had some real issues going from a lycoming to the conty, had a surefly installed last month which helped dramatically. In addition I have a new to me procedure from a bonanza pilot which has worked 5-6 times in a row.

1. mixture full rich
2. Throttle closed.

3. Low boost pump on

4. crank and increase throttle while cranking and like Mike said it finds its happy point and starts.

Procedure in old bonanza POH, but not n our Acclaims 

BTW I’m actually starting to like the acclaim

 

 

 

 

 

 

[Fly Boomer]

7 hours ago, dkkim73 said:

Following this thread with great interest as a new Acclaim owner (plane still elsewhere). If you'll forgive a minor thread deviation ("Moon Flight, turn right 10 degrees, vectors for newbie"), what are some good references for understanding operational principles and best practices for the TSIO-550G, and similar powerplants? 

I started going through the intro portions of John Deakin's online engine course and will probably do the whole thing. So far it is focusing more on combustion theory, leaning, etc. 

Any advice appreciated. 

David

Read this

https://www.avweb.com/features_old/operating-tips-for-big-bore-continentals/