RV-14 Simply Will Not Hot Start (and x-ed out fuel pressure sensor)

[samgaddis]

I have a 14 with the IO-390 and an unusual problem. After a flight, we cannot get this thing to start. We’ve tried a variety of hot start procedures to no avail.

Cold starts work great every time. Hot start procedure #1 is to keep boost pump on with mixture lean and slowly bring it to full as the engine starts to turn over. Procedure #2 is to set full throttle, boost pump on, mixture forward until stable fuel flow, then back to lean, engage starter, and finally reduce throttle and increase mixture as engine turns over.

Perhaps you have an idea for a different hot start procedure, but I can assure you both of the above worked great for a long time. If #1 didn’t work, #2 always worked. Then they both suddenly stopped working.

Some notes on the issue:

• When this occurs, on the G3X the fuel pressure will actually x-out (shows an x over the instrument) rather than reading zero
• About a year ago the boost pump was moved by my mechanic from the bottom of the engine (pilot side), to near the top of the engine on the co-pilot side near the firewall. This was to remedy an issue in which the fuel flow would show a decrease of 1gph whenever the boost pump was turned on during cruise. That wasn’t necessarily a problem, but he attempted to fix it by moving the boost pump position claiming that the previous position caused there to be an air bubble in the pump that reduced the fuel flow sensor reading.

My suspicion is that moving the boost pump caused a vapor lock issue due to the pump being in an area of higher heat. But I don’t know enough to say that with any confidence.

And also, if that’s the case, why would the fuel pressure sensor be x-ing out? And why does that sensor show an x-ed out reading only when the engine is hot?

 

[rvbuilder2002]

• About a year ago the boost pump was moved by my mechanic from the bottom of the engine (pilot side), to near the top of the engine on the co-pilot side near the firewall. This was to remedy an issue in which the fuel flow would show a decrease of 1gph whenever the boost pump was turned on during cruise. That wasn’t necessarily a problem, but he attempted to fix it by moving the boost pump position claiming that the previous position caused there to be an air bubble in the pump that reduced the fuel flow sensor reading.

Do you really mean to say boost pump? Or did you mean fuel flow sensor?

Regardless, hard starting problems are often ignition related?
What do you have for ign. systems?
If magnetos, I would have someone look at the internal mag timing.
Especially if the timing has been found off during condition inspections, and the mag. / engine time readjusted to correct it.

 

[Bdflies]

When hot, leave mixture at idle cutoff. Open throttle 1/4”. Boost pump OFF, both mags ON. Crank engine. When the engine begins to come alive, right hand ease in the mixture. When the engine clears and starts running, left hand moves from starter button to throttle, easing back to high idle. This works every time, for me.
Your "X'd" out fuel pressure is a mystery!

Bill

 

[Jparrish1]

"When hot, leave mixture at idle cutoff. Open throttle 1/4”. Boost pump OFF, both mags ON. Crank engine."
This is the exact procedure we use and works great for us too.

 

[bobrath]

As I understand it, when we shut these injected Lycomings down, the fuel system is left in a semi-flooded condition. Additional fuel (initially) isn't necessary. I crack the throttle, crank the engine and bring the mixture open as the engine begins to fire. Has worked well so far.

 

[samgaddis]

Do you really mean to say boost pump? Or did you mean fuel flow sensor?

Yes, it was the boost pump that was moved, not the fuel flow sensor.

Regardless, hard starting problems are often ignition related?
What do you have for ign. systems?
If magnetos, I would have someone look at the internal mag timing.
Especially if the timing has been found off during condition inspections, and the mag. / engine time readjusted to correct it.

It’s dual pmags. Interesting theory that it could be timing related. Any idea why that would affect hot starts only?

 

[rvbuilder2002]

Yes, it was the boost pump that was moved, not the fuel flow sensor.


It’s dual pmags. Interesting theory that it could be timing related. Any idea why that would affect hot starts only?

I said if you have traditional magnetos…
They can have issues develop that Pmags won’t.

Hot starts can produce a more difficult fuel/air mixture to ignite where a weak spark can come into play. Especially if a less than ideal starting technique is being used.

A electric fuel boost pump would never be mounted on top of the engine.
Moving the fuel flow sensor there would be a normal thing to do to try and reduce the indication error induced when the pump is on.

The starting procedure posted by Bill above is considered the most universally successful process that pretty much works with any fuel injected RV, and is what I always do.
If you don’t get success using it, have the ignition system looked at.

 

[RViator60]

I have a 14 with the IO-390 and an unusual problem. After a flight, we cannot get this thing to start. We’ve tried a variety of hot start procedures to no avail.

Cold starts work great every time. Hot start procedure #1 is to keep boost pump on with mixture lean and slowly bring it to full as the engine starts to turn over. Procedure #2 is to set full throttle, boost pump on, mixture forward until stable fuel flow, then back to lean, engage starter, and finally reduce throttle and increase mixture as engine turns over.

Perhaps you have an idea for a different hot start procedure, but I can assure you both of the above worked great for a long time. If #1 didn’t work, #2 always worked. Then they both suddenly stopped working.

Some notes on the issue:

• When this occurs, on the G3X the fuel pressure will actually x-out (shows an x over the instrument) rather than reading zero
• About a year ago the boost pump was moved by my mechanic from the bottom of the engine (pilot side), to near the top of the engine on the co-pilot side near the firewall. This was to remedy an issue in which the fuel flow would show a decrease of 1gph whenever the boost pump was turned on during cruise. That wasn’t necessarily a problem, but he attempted to fix it by moving the boost pump position claiming that the previous position caused there to be an air bubble in the pump that reduced the fuel flow sensor reading.

My suspicion is that moving the boost pump caused a vapor lock issue due to the pump being in an area of higher heat. But I don’t know enough to say that with any confidence.

And also, if that’s the case, why would the fuel pressure sensor be x-ing out? And why does that sensor show an x-ed out reading only when the engine is hot?

Never had a hot start problem in my RV14. Never use the boost pump, just open throttle slightly, mix cut off, then full rich when engine turns over. Maybe you’re flooding engine.

 

[n982sx]

I too believe you may be flooding the engine. My procedure is the same as others have listed. Mixture at idle cut off, throttle at least a 1/4" (to allow in more air), no boost pump, crank and push in the mixture slowly when it catches. Always works for me.

I also don't understand the moving of the boost pump location.

 

[Toobuilder]

Hot start procedure #1 is to keep boost pump on with mixture lean and slowly bring it to full as the engine starts to turn over. Procedure #2 is to set full throttle, boost pump on, mixture forward until stable fuel flow, then back to lean, engage starter, and finally reduce throttle and increase mixture as engine turns over.

Both of these techniques are flooding an engine which is already flooded. You want to “clear” the engine on a hot start, not dump more fuel in. You want NO fuel, and LOTS of air. Do NOT reintroduce more fuel until the engine fires up and starts to smooth out.

There are hundreds of posts on this site describing the proper hot start technique, and they all support those described in this thread.

I’m also wondering what is going on with the location of the boost pump. Generally speaking, you want it to be as low as possible relative to the fuel level. Not sure what the thinking was to go high on the firewall. Do you have pictures?

 

[edclee]

Check your spark plug gaps. They should be .016 for magnetos. If they are much wider, which they will get to at some point, like .020 they will likely not produce a spark from a magneto. This could account for your "suddden" starting problem. They simply wore wider and wider until now it wont start hot. Eventually it wont start cold either.
Ed

 

[rvanstory]

And also, if that’s the case, why would the fuel pressure sensor be x-ing out? And why does that sensor show an x-ed out reading only when the engine is hot?

I've gotten that big red X a few times on hot summer days before a hot start. Pressure has built up in the fuel lines to a point that exceeds your pressure sensors "top end" read out. (I think it tops out at 40 psi, but I can't recall offhand) To remedy, before doing anything else, simply move mixture knob to full rich (do NOT turn on boost pump). With mixture at full rich, the built up pressure will be released. The red X will go away and you can watch your pressure come down to near zero. Once pressure is released, move mixture from full rich to idle cut-off. To then start, I leave mixture at idle cut-off, go 1/2 throttle, and start cranking. If it does not fire immediately, I slowly move the mixture in as I crank. Once it fires and clears, move throttle back to idle and mixture to full rich.

 

[PandaCub]

We had a similar problem with the IO-360-M1B in my RV-8. It would cold start just fine, but hot starts regularly threatened to leave me stranded in the most inconvenient places. The problem stumped both me AND my A&P, who has a virtual black belt in the Art of the Hot Start.

To the best of my recollection, we finally traced it down to the impulse coupling in the left magneto, which I understand is pivotal during the engine starting process. We replaced the mag and now it reliably roars to life using standard hot start procedures.

 

[swjohnsey]

Another variant that works for me: Throttle 1/4, mixture idle cut off, boost pump on to pressurize system then off. Crank 'til it fires then mixture rich. It will take around 10 blades to hit so don't give up too early.

 

[vic syracuse]

You are flooding it. Never use the boost pump on a hart start. Just start cranking and when it begins to fire slowly work the mixture in.

 

[BillL]

1.The fuel system from the servo to the intake is open, no valve, no pintle, nothing just distributor and a pipe.
2.When it is shut down the mixture knob blocks fuel from the servo back to the mechanical pump check valve, trapping it.

3. #1 - rapidly after the engine is shut down, this fuel boils and pushes all the fuel into the intake thereby flooding the engine. This is why you leave the MIX in the closed/off position for starting.

4. #2 - the fuel trapped between the pump inlet and servo has expansion, not vaporization, and if you used 5000 psi fuel hoses, the expansion has exceeded the pressure limit of the sensor. i.e. X'ed out. A long explanation is better, but that is the basic. You should ensure you have the high pressure tolerant sensor or it can come apart and leak fuel. Nothing to do with starting, just catching your plane on fire.

The above are the facts. Accordingly, I open the throttle to what would be 1000 rpm, lock it then use one hand on the switch/button and one on the mix. The previous has addressed the hand dance. Locking throttle allows you to catch and modulate the mixture while cranking and go full throttle accidentally. YMMV on this last section.

 

[RONSIM]

1.The fuel system from the servo to the intake is open, no valve, no pintle, nothing just distributor and a pipe.
2.When it is shut down the mixture knob blocks fuel from the servo back to the mechanical pump check valve, trapping it.

3. #1 - rapidly after the engine is shut down, this fuel boils and pushes all the fuel into the intake thereby flooding the engine. This is why you leave the MIX in the closed/off position for starting.

4. #2 - the fuel trapped between the pump inlet and servo has expansion, not vaporization, and if you used 5000 psi fuel hoses, the expansion has exceeded the pressure limit of the sensor. i.e. X'ed out. A long explanation is better, but that is the basic. You should ensure you have the high pressure tolerant sensor or it can come apart and leak fuel. Nothing to do with starting, just catching your plane on fire.

The above are the facts. Accordingly, I open the throttle to what would be 1000 rpm, lock it then use one hand on the switch/button and one on the mix. The previous has addressed the hand dance. Locking throttle allows you to catch and modulate the mixture while cranking and go full throttle accidentally. YMMV on this last section.

I have a 14 with the IO-390 and an unusual problem. After a flight, we cannot get this thing to start. We’ve tried a variety of hot start procedures to no avail.

Cold starts work great every time. Hot start procedure #1 is to keep boost pump on with mixture lean and slowly bring it to full as the engine starts to turn over. Procedure #2 is to set full throttle, boost pump on, mixture forward until stable fuel flow, then back to lean, engage starter, and finally reduce throttle and increase mixture as engine turns over.

Perhaps you have an idea for a different hot start procedure, but I can assure you both of the above worked great for a long time. If #1 didn’t work, #2 always worked. Then they both suddenly stopped working.

Some notes on the issue:

• When this occurs, on the G3X the fuel pressure will actually x-out (shows an x over the instrument) rather than reading zero
• About a year ago the boost pump was moved by my mechanic from the bottom of the engine (pilot side), to near the top of the engine on the co-pilot side near the firewall. This was to remedy an issue in which the fuel flow would show a decrease of 1gph whenever the boost pump was turned on during cruise. That wasn’t necessarily a problem, but he attempted to fix it by moving the boost pump position claiming that the previous position caused there to be an air bubble in the pump that reduced the fuel flow sensor reading.

My suspicion is that moving the boost pump caused a vapor lock issue due to the pump being in an area of higher heat. But I don’t know enough to say that with any confidence.

And also, if that’s the case, why would the fuel pressure sensor be x-ing out? And why does that sensor show an x-ed out reading only when the engine is hot?

If you have traditional mags, make sure your impulse coupler is working. If you do not have an impulse coupler, then you have a retard mag and it requires a Slickstart to give you the extra spark for starting. In the future, consider replacing one mag with a Surefly.

 

[bertschb]

If you have traditional mags...

He has dual P-Mags

 

[Toobuilder]

…About a year ago the boost pump was moved by my mechanic from the bottom of the engine (pilot side), to near the top of the engine on the co-pilot side near the firewall. This was to remedy an issue in which the fuel flow would show a decrease of 1gph whenever the boost pump was turned on during cruise. That wasn’t necessarily a problem…

First off, there are hundreds of posts on this site describing the behavior of FF transducers in response to boost pump operation (just like there are plenty of “hot start” posts). Please do a search and sit down for some lengthy reading.

Second, need to see what your mechanic did here because it does not make sense (based upon your description). There is a good chance that this attempted fix for a condition that “…wasn’t necessarily a problem…”, has made your life harder.

 

[jcarne]

Does moving the mixture control in before start not change the red X condition on the fuel pressure guage? Also does the mixture control feel different when moved?

I was having a similar issue. My Dynon system will show a red X when the pressure gets above 150 (which unseats the mixture control from the mixture plate). See my thread below, especially post 4, you may be having a similar issue that the techs at Avstar helped me figure out. Haven't had an issue since changing my shutdown procedure slightly.

Also, if moving the boost pump a year ago was the cause I'm betting you would have seen this issue sooner.

Calling all RSA experts. Weird one here...

Okay gents, there I was today on a fuel stop before heading the 20ish miles back home after topping off. Went to start and noticed my Dynon didn't show fuel pressure which is relatively normal once it crosses 150psi after a quick turn where the engine heat causes a pressure rise in the fuel...

vansairforce.net

 

[Bavafa]

Like many have already said, you are flooding the engine. Try it without the boost pump at all. If cracking the throttle 1/4 is not working well, try it with WO and as you start cranking, pull the throttle slowly back. At some point the air/mixture becomes just right for the engine to catch, at this point push the mixture in slowly.
In regards to the boost pump, this would be the first 14 with the boost pump in the FFW if in fact it is there and seems very unusual. The standard install place is in the tunnel just in the front of the fuel selector valve.
If your fuel pressure is getting a red X ,that usually means that Garmin does not see it and I would suspect a wiring issue. It is possible that when it gets hot, it effects the connection.

 

[larrynew]

Lycoming’s unofficial hot start procedure. Picture taken from a class they gave at Oshkosh in 2016.

 

[Toobuilder]

Lycoming’s unofficial hot start procedure…

Wrong as a soup sandwich.

 

[mburch]

the fuel trapped between the pump inlet and servo has expansion, not vaporization, and if you used 5000 psi fuel hoses, the expansion has exceeded the pressure limit of the sensor. i.e. X'ed out.

From the description posted, it seems plausible this is what is happening. If you have Kavlico pressure sensors, I would verify you have followed the service bulletin on this topic. There are "improved" Kavlico sensors that aren't subject to the same issue (P4055-5020 series), or Garmin has their own private-label pressure sensors which I believe are now the default choice. I complied with the SB by installing one of the latter, which is specified at 75 PSI working pressure versus the old one which was a 50 PSI unit.

 

[rvbuilder2002]

I've gotten that big red X a few times on hot summer days before a hot start. To remedy, before doing anything else, simply move mixture knob to full rich (do NOT turn on boost pump). With mixture at full rich, the built up pressure will be released. The red X will go away and you can watch your pressure come down to near zero. Once pressure is released, move mixture from full rich to idle cut-off. To then start, I leave mixture at idle cut-off, go 1/2 throttle,

Doing this is actually counterproductive because it introduces even more fuel to an engine that is probably already flooded.
It will just make the start even more difficult.
The red X is a function of the system, pressure being above what the sensor or the sensors calibration is rated for and irrelevant to getting a good start.

 

[samgaddis]

If you have traditional mags, make sure your impulse coupler is working. If you do not have an impulse coupler, then you have a retard mag and it requires a Slickstart to give you the extra spark for starting. In the future, consider replacing one mag with a Surefly.

I have dual pmags. Can you clarify given that? Is a slickstart still relevant

 

[Mike S]

Sounds like a purge valve may be helpful.

What fuel injection are you using?

 

[Carl Froehlich]

I have dual pmags. Can you clarify given that? Is a slickstart still relevant

The short answer is no.

pMags are designed to retard timing during engine start - like a few degrees ATDC. This is very advantageous to getting the engine to fire during cranking. Once running the pMags advance timing back to normal. In other words the pMags are doing their part to start the engine. The comments are fairly consistent you are flooding the engine, I agree.

If you find you have a flooded engine, recommend:
- Both pMags on (if you are using a key switch verify that both pMags are on when the switch goes to start)
- Mixture at cutout
- Throttle wide open
- Crank the engine
- When the engine fires, bring back the throttle to fast idle (cracked)
- Advance the mixture to your lean idle setting

The wide open throttle provides the extra air to counter the extra fuel in your flooded engine.

On moving the boost pump up on the firewall, no clue why you did that. I suggest putting it back in the per plans location.

On the fuel sender reading wrong when you turn on the boost pump, I assume this is because it is not mounted on the output side of the engine driven fuel pump (as the install instructions specify).

Carl

 

[samgaddis]

We’ve tried all the various hot start procedures recommended (not all at once but at different times).

The boost pump is not on top of the engine. It’s aft of the firewall. The fuel flow transducer is what was moved - my mistake earlier claiming it was the boost pump. Here’s the logbook entry for that:

“Fabricated new FT-60 mounting bracket and installed on oil sump flange. Mounted FT-60 with new steel fittings. Installed new fuel line from fuel pump T fitting to fuel servo. Installed new fuel line from fuel servo to FT-60. Connected existing fuel line from FT-60 to flow divider. Pressurized system. Ran engine. Operational check OK.”

The theory’s proposed so far include:

• Poor hot start procedure causing flooding (have tried everything recommended on that)
• spark plug excess gap
• Boost pump mounted too high (it’s not on top of the engine but…
• Bad impulse couple on the magneto (relevant to pmags?)
• Fuel line running to spider from below the engine up between the cylinders (see image)

I’m noticing when I look at other IO-390 installs that the fuel line never runs up through the cylinders as mine is shown.

Related observations:

• 2nd cylinder rumbles when it’s hot as well. EGTs oscillate up and down until run up complete. Never an issue in flight
• When engine cold - sensor showing - no rumble and it starts
• When engine at mid temp - sensor shows and pressure decreasing - starts but rumble
• When engine hot - no sensor - no start

 

[Carl Froehlich]

We’ve tried all the various hot start procedures recommended (not all at once but at different times).

Poor hot start procedure causing flooding (have tried everything recommended on that)

• spark plug excess gap
• Boost pump mounted too high (it’s not on top of the engine but…
• Bad impulse couple on the magneto (relevant to pmags?)
• Fuel line running to spider from below the engine up between the cylinders (see image)

- Spark plug gap for NGK IKH27 long reach plugs should be 0.030” to 0.035”
- Are you using long reach plugs and the long reach plug adapters?
- As discussed, pMags do not use anything like an impulse coupler
- Every engine I put in an RV has the fuel line running up to the spider as shown in your photo
- Is the boost pump mounted in the per plans location?
- Where is the red cube now located? A photo would help.

So, if you are confident that you are using a good procedure and are still having a problem look at other stuff, like:
- Timing. For your engine timing should be 20 degrees BTDC. To set this using pMags follow the pMag install manual but set timing with the crank at 5 degrees ATDC. This compensates for the pMag base timing of 25 degrees BTDC if you set the pMags with the crank at TDC (in other words the pMag default assume a parallel valve Lycoming).

Carl

 

[rvbuilder2002]

We’ve tried all the various hot start procedures recommended (not all at once but at different times).

The boost pump is not on top of the engine. It’s aft of the firewall. The fuel flow transducer is what was moved - my mistake earlier claiming it was the boost pump. Here’s the logbook entry for that:

“Fabricated new FT-60 mounting bracket and installed on oil sump flange. Mounted FT-60 with new steel fittings. Installed new fuel line from fuel pump T fitting to fuel servo. Installed new fuel line from fuel servo to FT-60. Connected existing fuel line from FT-60 to flow divider. Pressurized system. Ran engine. Operational check OK.”

The theory’s proposed so far include:

• Poor hot start procedure causing flooding (have tried everything recommended on that)
• spark plug excess gap
• Boost pump mounted too high (it’s not on top of the engine but…
• Bad impulse couple on the magneto (relevant to pmags?)
• Fuel line running to spider from below the engine up between the cylinders (see image)

I’m noticing when I look at other IO-390 installs that the fuel line never runs up through the cylinders as mine is shown.

Related observations:

• 2nd cylinder rumbles when it’s hot as well. EGTs oscillate up and down until run up complete. Never an issue in flight
• When engine cold - sensor showing - no rumble and it starts
• When engine at mid temp - sensor shows and pressure decreasing - starts but rumble
• When engine hot - no sensor - no start

Observation -
Some info you have provided in this thread you started has been wrong.
This makes it very difficult for others who only have what you have typed, to go on, to try and help you.

Example - you are now listing "Boost pump mounted too high" as an issue because someone mistakenly misunderstood you being certain that it was now mounted on top of the engine but they thought you meant moved to the firewall (ever play the kids game telephone), when it actually was just the fuel flow sensor that was moved.

Another - It has already been mentioned that Pmags don't have an impulse coupling

Another -
In this post you say "I’m noticing when I look at other IO-390 installs that the fuel line never runs up through the cylinders as mine is shown."
This also isn't like true.
It is pretty much a universal standard for any Lycoming style engine with the traditional fuel injection like your engine is probably equipped with, to have a hose passing through the inter cyl baffle and running vertical between the #1 and #3 cyl, and making a connection at the fuel distribution block.

If you have actually properly used the recommended starting procedure (not the one from Lycoming shown in the photo shot during a forum), and it still wont hot start (I suspect that it hasn't been done correctly, because if it has, with dual Pmags, it should start) then the best advice is for you to have someone that knows about ign. systems, Pmags specifically, look at all aspects of the system for you (such as confirming they are properly timed to the engine, that you are operating them correctly, etc.)

Lastly - I have no idea what you mean when you say a Cyl "rumbles"

 

[samgaddis]

Observation -
Some info you have provided in this thread you started has been wrong.
This makes it very difficult for others who only have what you have typed, to go on, to try and help you.

You are absolutely right that some of the info I initially provided was wrong. My apologies. I'm not in the same state as the airplane right now so it's difficult for me to gather info and logbook entires from my partner who's currently using the plane for some training. I'm trying to help sort things out remotely and have made a few errors. Doing my best to learn and provide accurate info.

Lastly - I have no idea what you mean when you say a Cyl "rumbles"

As I said the EGT oscillates. To expand on this - it's only on cylinder 2. The EGT oscillation is about 100 degrees over a period of a few seconds. It's audible to the ear and sounds like...well, rumbling.

 

[Bavafa]

You are absolutely right that some of the info I initially provided was wrong. My apologies. I'm not in the same state as the airplane right now so it's difficult for me to gather info and logbook entires from my partner who's currently using the plane for some training. I'm trying to help sort things out remotely and have made a few errors. Doing my best to learn and provide accurate info.



As I said the EGT oscillates. To expand on this - it's only on cylinder 2. The EGT oscillation is about 100 degrees over a period of a few seconds. It's audible to the ear and sounds like...well, rumbling.

I wouldn't worry about the EGT oscillation over a few second, at least at this point. It is not clear where you are located, but it may not be a bad idea to meet up with some local RV guys to get acclimated with the setup of the RV and what is where and how. The fuel line to the spider is pretty standard as you have it. Also, it has not been helpful that some of the folks have not read the details of your setup and then provide suggestions (like impulse coupler, etc) This only confuses things.
The suggestion for the correct timing and long reach spark plugs are a very good one, especially the timing as setting up the timing for PMAG is different than traditional mag, as well as for 390. PMAGs are timed at TDC and not the 20 or 25 BDC that is standard for traditional MAG.

 

[Desert Rat]

I get how difficult it might be to try and sort through all this stuff when you're out of town, but something isn't adding up here; are you 100% certain that the FT-60 was re-located up top by the co-pilot side of the firewall?

You said:

The fuel flow transducer is what was moved - my mistake earlier claiming it was the boost pump. Here’s the logbook entry for that:

“Fabricated new FT-60 mounting bracket and installed on oil sump flange. Mounted FT-60 with new steel fittings. Installed new fuel line from fuel pump T fitting to fuel servo. Installed new fuel line from fuel servo to FT-60. Connected existing fuel line from FT-60 to flow divider. Pressurized system. Ran engine. Operational check OK.”

This logbook entry you attached and that I've copied above specifically references fabricating a new FT-60 mounting bracket on an oil sump flange. The oil sump is on the bottom of the engine. The rest of that entry doesn't mesh with where you've said the FT-60 is either, as the plumbing routing and hose lengths required wouldn't be logical at all.

It's hard to tell, but what that entry implies to me is that the FT-60 was relocated from upstream of the servo to downstream of the servo and is likely still mounted on the bottom of the engine. If that's the case, and it happened to take either the FT-60 or an associated fuel line closer to an exhaust pipe I could see how that could cause you to suddenly have a vapor lock issue that didn't exist before. This is wild supposition on my part because as of now, it seem like we don't know for certain where anything is really located.

At this point, there's quite a bit of conflicting information in this thread. I suggest that it might be time to regroup, uncowl it when you get back home and take some pictures of what you actually have going on here.

 

[samgaddis]

At this point, there's quite a bit of conflicting information in this thread. I suggest that it might be time to regroup, uncowl it when you get back home and take some pictures of what you actually have going on here.

Yes, I'm seeing now how much conflicting info I've posted. My apologies and thank you all for forcing me to better understand what's going on. I didn't understand these systems well enough but things are starting to clear up now.

Fuel flow transducer was moved to the oil sump. I can see how that could cause a vapor lock. We're going to get it to a mechanic where it is (in Kansas) and discuss moving the transducer back to where it was originally. Will post pics when I receive them.

 

[Bavafa]

Yes, I'm seeing now how much conflicting info I've posted. My apologies and thank you all for forcing me to better understand what's going on. I didn't understand these systems well enough but things are starting to clear up now.

Fuel flow transducer was moved to the oil sump. I can see how that could cause a vapor lock. We're going to get it to a mechanic where it is (in Kansas) and discuss moving the transducer back to where it was originally. Will post pics when I receive them.

I don't think this is part of your problem unless some weird setup was done. It will help if you post a picture of the new location.
FYI, your original position is where VANS recommend is for the RV14 and most have them there. Some folks, especially on other models, have installed them where your new location is and all have been good. The recommendation from Red Cube is to put them there but also no elbow type fitting close to the transducer.

 

[RONSIM]

I have dual pmags. Can you clarify given that? Is a slickstart still relevant

No Slickstart required --- your P-mags should be set to fire at TDC for STARTING and will light up (usually) most reluctant engines.

 

[Tim Lewis]

Lycoming’s unofficial hot start procedure. Picture taken from a class they gave at Oshkosh in 2016. View attachment 57440

Larry New's "unofficial Lycoming hot start" photo shows a process very similar to the hot start procedure I use on my fuel injected RV-10. This procedure is similar to the hot start procedure outlined in the Lycoming operating manual (pages 3.2 and 3.3) for the IO-540-C4B5/D4A5. https://www.lycoming.com/content/operator's-manual-O-540-IO-540-60297-10-3

Lycoming's method on page 3.2:
Throttle 1/4" open
Boost pump on
Mixture to full rich until fuel flow
Mixture idle cut off
Engage starter
When engine starts, move mixture to full rich

The modification to this procedure that I have found useful during hot start is to set the throttle at full open (WOT) during the above process. It is my understanding this approach floods the engine while clearing fuel vapor from the fuel lines. Then, while cranking, the mixture in the cylinders transitions from "too rich" (flooded) through "just right", at which point the engine starts. Obviously, one has to be prepared to rapidly pull the throttle back to idle as soon as the engine starts.

FWIW, I have my red cube suspended in the fuel line that runs from the fuel injection servo to the spider. Mine is covered in fire sleeve. It is NOT bolted to the engine. This mounting method is depicted on page 20 of the installation instructions, https://iflyei.com/wp-content/uploads/FP-5L-II.pdf

 

[Desert Rat]

Oh, one more thing. The post right above this one reminded me; If you're really wanting to move that fuel transducer from the bottom of the engine, one option is that Aircraft Specialty/TS Flightlines makes a kit that locates it right at fuel distribution spider.

https://www.aircraftspecialty.com/PDF%20Documents/FT-60%20Transducer%20Mount.pdf

I have no experience with this other than to know that it exists.