Help...dead in the water, air in fuel lines!!!

[DDW]

Starting fluid is ether or some other very volatile mix, if you are just trying to get it to run without fuel, WD-40 works pretty well.

I always thought you should crack ALL of the injector lines on a mechanically injected engine to bleed air. The injector pump is usually a cam operated plunger for each cylinder. It expects a noncompressible fluid to be in the line to the injector. When the plunger gets pushed, the fluid in the line has to reach the release pressure of the injector or nothing (including the air) will get pushed through. If it's full of air, it will come nowhere close to this pressure and just bounce back. It will do this forever, even if the pump is full of fuel. If you crack only one line, all the others will still be full of air as each circuit is isolated. The injector isn't just a nozzle, it has a check valve that requires a certain pressure to open to prevent after dribble etc.

None of this is true of a common rail engine which have a 20,000 - 30,000 psi pump on the rail, and a return path for spill fuel and air.

 

[High Wire]

Wd40 uses PROPANE for propellant. That’s what the engine is starting on.

 

[Madhatter53]

Spray bottle with some fresh deisel would work in a pinch.

 

[Wxx3]

These are from the manual for the 225. The injector pump does not need to be bleed. It has a self purge device according to the book.

And the many times I've starved my engine for fuel and let air get in, i've never touched the injection pump.
Once i have fuel flowing from the bleed screws on top of the secondary engine mounted filters, it's good to go.
(Assuming you filled the racors to overflowing, before you tightened them up).
Good luck

 

[Comodave]

As I said previously when I bleed mine I just get the secondary filters full. Then start at a high throttle setting. I have never cracked an injector line. And per Bob Smith in his seminar, cracking the injector lines is not necessary.

 

[AusCan]

As a proud Lehman owner, with all their features good (mostly) and less good, I`ve wondered if there are marine diesels,younger than 40+ years of age, which self bleed?
PS I`ve never had to use it but I saw in the engine bay of my diesel Peugeot 508, a pumping bulb which I imagine comes in handy if you run out of fuel.

My Vetus self bleeds with its electric fuel pump. I love it.

 

[BruceK]

My Vetus self bleeds with its electric fuel pump. I love it.

The Kubota driving my Onan almost self bleeds. Open one set screw which turns out to be a ? banjo screw. Didn`t even have a manual, found a screw near the fuel pump with paint worn off the head.

 

[Steve91T]

Finally made it back home to NC and have time to explain more about what happened.

My boat has Lehman 225’s with four, 150 gallon fuel tanks.

We spent 2 nights at the ancorage. I had transferred fuel to the aft starboard tank to level the boat from a fuel imbalance. I had roughly 30-40 gallons in that tank after transferring. We spent a lot of time on the island and only ran the generator when we needed it. It was off the first night but we wanted AC for the 2nd night. So we ran it about 8 hours that night. Knowing the genny doesn’t use much fuel, I had no doubt we had plenty of fuel still in the starboard tank to get us out of the ancorage. We had to leave at low tide and it was a super shallow area. So we took our time and idled our of there with my buddy helping me spot the shallow areas. Once clear of that I ran her up to 1650 rpm and was going to hang a right at the next green marker which was the ICW. Once there I was going to let my buddy drive while I went into the engine room and adjusted fuel valves and do a once over. We were maybe 1/4 mile away from the ICW when the starboard engine flamed out. I knew instantly what it was and pulled the port engine to 1000 RPM. Told my buddy really quickly the plan and as I ran off the fly bridge, the port engine flamed out. I got to the engine room just as the generator also flamed out. I looked at the fuel tanks. That is when I realized that I had just ran out of fuel with 300 gallons on board. Awesome.

What had happened was that even though I had tons of fuel in the starboard aft tank, the generator only returns to either the port forward or aft tanks. Since I had left the manifold set to pull from the starboard aft tank, I was Essentially transfering fuel out of the starboard tank to the port tank. What sucks is I was minutes from catching my mistske.

The other odd thing is why my electric priming pump lost prime. It pulls from the aft starboard tank, the same one I ran dry. Maybe I flipped it on before transferring fuel, I’m not sure. But once I transferred fuel to that tank, it finally Found it’s prime. But it took a ton of fuel in that tank, which makes no sense because the pick up is at the bottom of the tank.

What is really odd though is why it took so long to get fuel out of the top of the injection pump. We did so much cranking with confirmed fuel to the pump that I was worried about killing the starter. And even hours later at the dock I could get it To run for seconds before dying. It must have done that 20 times. I would think once the engine catches and runs up to 1200 rpm, it should be able to continue running.

I’m call AD tomorrow and see what they think.

It took us 4 hours of non stop bleeding and transfering and cranking to get 1 engine started. That’s crazy.

 

[Comodave]

Yes, but you are definitely good at bleeding it now, right?

 

[Captain DJ]

As a proud Lehman owner, with all their features good (mostly) and less good, I`ve wondered if there are marine diesels,younger than 40+ years of age, which self bleed?
PS I`ve never had to use it but I saw in the engine bay of my diesel Peugeot 508, a pumping bulb which I imagine comes in handy if you run out of fuel.

I know my old boat had older DD 4-53's but she would self prime without any trouble. I always thought it was a characteristic trade-off with the Detroits.
They can be loud and leakers, but they will never be finicky and can burp out air like a fat German at a beer garden.

Isn't that the case with 6-71's and other common old trawler engines?

 

[Steve91T]

Hey guys. So I know I said I had removed one injector line and cranked to see if we could get air or fuel out of the pump. I didn’t mention that at one point we had all of the lines cracked.

I spoke with American Diesel. Brian said never to undo the fuel lines, there is no reason with this pump as it is self bleeding. As to why I had such a hard time getting this starboard engine to run, he said there is a check valve in the fuel return line. If it gets stuck, it will not allow air out of the pump. He’s guessing that was my problem. Bleeding air out of this engine shouldn’t have been such an ordeal.

I have a 5.9 Cummins in my F350 truck. It’s very similar to the Lehman. I installed larger injectors over the summer and bleeding was as simple as cracking the first two injector lines and cranking it. Once it started to run I snugged up the injector lines and all was well.

The funny thing is the internet failed me. Usually I can find what I need to. But this time all I could find is about bleeding the 120 Lehman, which is a different animal. I didn’t read anything about this return line check valve. Which I had because it would have probably turned a 4 hour job into a 15 minute job.

Oh well, now I know.

 

[thataway]

Wd40 uses PROPANE for propellant. That’s what the engine is starting on.

Although at one time WD 40 used an extremely volitive propellant, now WD40 in the spray can, uses CO2, (2-3%) which is non explosive. The currently "explosive" part of WD40 is a Aliphatic Hydrocarbon which is explosive class 3 and is <25%.
There is about 50% LVP Aliphatic Hydrocarbon which has a flash point which is 30 to 70 degrees F. higher than diesel. The remainder is petroleum base oil.

I once had to bleed a Ford Lehman (single engine vessel) when it stopped as we had cast off from the tug we had rafted next do, on the down locking to the Caribbean. The large ship behind us had started to make way. I recognized that it had sucked in air when given WOT at the suggestion of the Panama Canal advisor (pilot in training for yachts), The boat made a fairly slow (but it seemed fast) 360* turn by the time the engine fired. I guessed about 2 minutes. But, I immediately switched fuel tanks, turned on the fuel pump, and grabbed the wrenches kept right by the engine, and labeled with which fittings they were for.

In other words--always know how, and be prepared to bleed that pump in a emergency. In this case, I found a crack in pick up tube--from one tank. I had spare tubing and fabricated a new pickup that night at anchor.

The other good lesson here, is to always know where the return fuel is going!

 

[Andiamo2018]

Perkins and Volvo priming

In my limited experience with Perkins engines they are very touchy to bleed. More than any other engine I have worked on. Volvo's all were very easy, easy to the point of never ​needing to ​bleed them LOL​. They don't have glow plugs and never hesitate after changing the filters. It's like magic ​Sort of the opposite of what it is like ​when it comes time to pay for parts for them.​

 

[Manny]

My Gardner has 2 bleed screws on the injector pump, instead of pumping for 72hours, I just remove the screws and fill with diesel.

Turning the engine without fuel in the injector pump is not a great idea as the diesel lubricates the pump.

 

[Comodave]

Hey guys. So I know I said I had removed one injector line and cranked to see if we could get air or fuel out of the pump. I didn’t mention that at one point we had all of the lines cracked.

I spoke with American Diesel. Brian said never to undo the fuel lines, there is no reason with this pump as it is self bleeding. As to why I had such a hard time getting this starboard engine to run, he said there is a check valve in the fuel return line. If it gets stuck, it will not allow air out of the pump. He’s guessing that was my problem. Bleeding air out of this engine shouldn’t have been such an ordeal.

I have a 5.9 Cummins in my F350 truck. It’s very similar to the Lehman. I installed larger injectors over the summer and bleeding was as simple as cracking the first two injector lines and cranking it. Once it started to run I snugged up the injector lines and all was well.

The funny thing is the internet failed me. Usually I can find what I need to. But this time all I could find is about bleeding the 120 Lehman, which is a different animal. I didn’t read anything about this return line check valve. Which I had because it would have probably turned a 4 hour job into a 15 minute job.

Oh well, now I know.

Didn’t I say not to crack the injector lines??? Two times...

 

[Steve91T]

Didn’t I say not to crack the injector lines??? Two times...

You didn’t say it loud enough

 

[Steve91T]

Didn’t I say not to crack the injector lines??? Two times...

In all seriousness, looking things up on the internet requires the ability to sift through the ****. The majority of the advice on here and the rest of the internet was to crack the injector lines. This is also true for my Cummins. It’s not necessary but it helps. That’s why I chose to crack 1 line. I did it so I could see if fuel was coming out and also to allow any trapped air out.

We also did try with everything tightened up...a lot. We also cracked all 6 lines. We were trying everything.

AD even said that bleeding the block mounted filters wasnt necessary. They said these engines are self bleeding and should have just fired right up....that wasn’t our case.

I need to look at those check valves in the return lines.

Such a head ache for a simple oversight of where the fuel was returning to.

 

[Comodave]

Ok, next time I will post in all caps... But seriously, I have the same engines.

 

[Peter B]

Coming in on this a bit late, I know, Steve, but our last outing in our boat before it sold, was ruined and cost me a heap for a tow-in, because being on the market, we had let our tow cover lapse. It, as in your case, failed from fuel starvation from the most simple of reasons, which like you, I was so close to solving, but didn't. The boat was a Clipper 34 with a 120 Lehman, which had never, ever, given trouble until this occasion, but died as we throttled off just as we came into an anchorage. I knew it was a fuel issue, and pumped the primer, and checked all the lines, but could only get the engine to fire for a bit then it would die again.

To cut to the chase, after the expensive tow in, the mechanic, who had seen this before, found that the last join of the fuel line above the lift pump into the injector manifold had worked just loose enough to let air bleed in and the engine would starve the minute one dropped revs, then die again, after a short burst which is characteristic of that surge of power from a lean mixture. It took about two nips up of that join to solve the whole problem. Still bugs me I missed it and it cost us our last, and what should have been my birthday cruise. You might just want to take a spanner to that same joint. Just sayin'

 

[Wxx3]

Been there, done that. All of that.

Learned not to use return fuel to transfer fuel lest one forgets!

Also, spent a week trying to get engine start. Turned out I'd unknowingly blocked the fuel return line. Wore a hole in my hand using the lift pump.

I got a 12v electric fuel pump, installed it before the racors and now use it to prime filters. Works great. Though initially, I installed it with only one valve and discovered it just pumped fuel around a closed loop, without priming anything.

Also learned to never feed from both tanks at the same time.

I thought about a installing a day tank. It would make my life less stressful, like when I arrived st the Panama Canal with only 15 gallons left. But decided against it since the current system is always pulling cool fuel from the tank. Since my fuel usage is so slow relatively, I'd end up with engine room temperature fuel, which wouldn't help anything.

 

[Cigatoo]

Been there, done that. All of that.

Learned not to use return fuel to transfer fuel lest one forgets!

Also, spent a week trying to get engine start. Turned out I'd unknowingly blocked the fuel return line. Wore a hole in my hand using the lift pump.

I got a 12v electric fuel pump, installed it before the racors and now use it to prime filters. Works great. Though initially, I installed it with only one valve and discovered it just pumped fuel around a closed loop, without priming anything.

Also learned to never feed from both tanks at the same time.

I thought about a installing a day tank. It would make my life less stressful, like when I arrived st the Panama Canal with only 15 gallons left. But decided against it since the current system is always pulling cool fuel from the tank. Since my fuel usage is so slow relatively, I'd end up with engine room temperature fuel, which wouldn't help anything.

Why do you not feed from both tanks at the same time?

 

[bridaus]

I'm sure it's been said, and I was thinking of fuel system design today, but this post is a prime example of why we should all have electric fuel pumps inline as backups. Simply turn the key, count to the appropriate number, and all air should be purged. (Unless I missed something, always that nagging feeling...).

 

[OldDan1943]

Greetings,
Mr. S. Just had a thought... Maybe y'all got some Yankee air into the system. Once them Yankees get into your system, they're dad-gummed hard to git rid of...

Or perhaps, Government air from Congress. LOL

Sorry.

 

[rolomart3]

I ran a fuel tank dry by accident and have air in the lines. We have found there is no fuel going to the fuel manifold. We have tried everything. We believe the air is in the fuel lines where they go up then back down into the manifold. Fortunately we have a full forward fuel tank. Currently transferring all fuel to an aft tank and hoping the fuel level will be higher than the highest point of the fuel line.


Any ideas?

Steve,


your pictures show the lower valves turned off!!!!!. Also, when air enters the input fuel lines (yes, there are also output fuel lines!!!) of some diesel engines, the only way to restart the engine is by bleeding the lines.


Bleeding the lines usually requires to manually operating the mechanical lift pump the engine powers to rise the diesel to a level where the injection pump can increase its pressure to above 18,000 PSI. If there is air, it will take a lot of pumping before the fuel displaces the air in the line. By then, the battery will be dead or the starter motor will be burnt.


So if the engine does not use an electrical lift pump, you need to find the mechanical lift pump. You need to find the point where there is no camshaft action on the pump by rotating the engine camshaft. At this particular point, the camshaft does not interfere with the action of the manual pump lever and one feels the full resistance of the pump plunger when manually pumping.



Now, you need to find bleeder screws in filter assemblies and the injection pump. Open these bleeder screws one by one starting from the tank towards the injection pump and manually drive back and forth the pump lever until straight fuel (no bubbles) come out through the bleeder screw. Tighten the screw and continue pumping until you notice a change in the resistance of the pump lever. Move to the next screw, loosen it and repeat the procedure. Usually, two screws are involved.



If you have done it correctly, the engine will start almost immediately upon cranking.



Please note that if there is air at some point or air is entering the fuel lines before the lift pump, the engine may quit again in a few minutes.



Install a $5 vacuum gauge in the fuel lines before the lift pump to show vacuum in the input fuel lines. Close the fuel valves feeding the engine and let the engine run at idle. If the vacuum gauge show increasing vacuum, the lines are fine. If it does not, there is a problem leak that needs to be fixed.



A leak past the lift pump is not as serious a problem, just the nuisance of a minuscule amount of fuel dropping down into the collector pan under the engine containing one of those oil absorbing pads (if you do not have a collector pan, do install one to prevent dumping fuel or oil into the bilge and then to the environment if the bilge pumps are designed to shutdown when gaining contact to oil or fuel; bad news: no operational bilge pumps).



Do not ask me how I know these bleeding details. It was a horrible trial and error experience with the lift pump resolved by the assistance from a good friend. I am just trying to pass the torch of friendship here.


Good luck,

 

[Steve91T]

Steve,


your pictures show the lower valves turned off!!!!!. Also, when air enters the input fuel lines (yes, there are also output fuel lines!!!) of some diesel engines, the only way to restart the engine is by bleeding the lines.


Bleeding the lines usually requires to manually operating the mechanical lift pump the engine powers to rise the diesel to a level where the injection pump can increase its pressure to above 18,000 PSI. If there is air, it will take a lot of pumping before the fuel displaces the air in the line. By then, the battery will be dead or the starter motor will be burnt.


So if the engine does not use an electrical lift pump, you need to find the mechanical lift pump. You need to find the point where there is no camshaft action on the pump by rotating the engine camshaft. At this particular point, the camshaft does not interfere with the action of the manual pump lever and one feels the full resistance of the pump plunger when manually pumping.



Now, you need to find bleeder screws in filter assemblies and the injection pump. Open these bleeder screws one by one starting from the tank towards the injection pump and manually drive back and forth the pump lever until straight fuel (no bubbles) come out through the bleeder screw. Tighten the screw and continue pumping until you notice a change in the resistance of the pump lever. Move to the next screw, loosen it and repeat the procedure. Usually, two screws are involved.



If you have done it correctly, the engine will start almost immediately upon cranking.



Please note that if there is air at some point or air is entering the fuel lines before the lift pump, the engine may quit again in a few minutes.



Install a $5 vacuum gauge in the fuel lines before the lift pump to show vacuum in the input fuel lines. Close the fuel valves feeding the engine and let the engine run at idle. If the vacuum gauge show increasing vacuum, the lines are fine. If it does not, there is a problem leak that needs to be fixed.



A leak past the lift pump is not as serious a problem, just the nuisance of a minuscule amount of fuel dropping down into the collector pan under the engine containing one of those oil absorbing pads (if you do not have a collector pan, do install one to prevent dumping fuel or oil into the bilge and then to the environment if the bilge pumps are designed to shutdown when gaining contact to oil or fuel; bad news: no operational bilge pumps).



Do not ask me how I know these bleeding details. It was a horrible trial and error experience with the lift pump resolved by the assistance from a good friend. I am just trying to pass the torch of friendship here.


Good luck,

Thanks for the response.

In that picture I was trying to get fuel from the tanks to the manifold. If you look again you’ll see I have the middle valve open (for the genny) and the hose removed so I could see when it was getting fuel. I was transfering fuel from the forward tanks to the aft tanks to get the fuel level high enough allow gravity to do its thing.

Once I had the manifold bled, I hooked up the generator and it started right up. So fortunately we had the generator recharging batteries the whole time.

Then I opened the port valve and started working on the port engine.

From there I learned about the block mounted pump and bled the filters. She still wasn’t starting though, even though the injection pump on the Lehman’s are self bleeding.

We finally gave up on that engine and turned our attention to the starboard engine. Once we got the block mounted filters bled, she started right up.

Something was wrong with the port engine fuel system apparently because it should have been so difficult to get it to start.

 

[Steve91T]

One thing on my list now is to install a return line from one side to the other. Right now the generator and the port engine can only return to the port side tanks, yet the can pull from either port or starboard tanks. The starboard engine can only return to the starboard tanks but can pull from the port.

If I’m running, say 2 hours, all valves open, I’ll get an inballance within 30 minute because I’m sure one tank is slightly more restrictive than the other. So I’ve started just pulling off of one tank or the other. But since one engine is always going to basically be transfering via fuel return, I’ll get an imbalance quickly as well. So even though I’m only burning about 4 gph, I’m moving a lot of fuel around. And it doesn’t take much to get a list, which drives me nuts.

I do have a transfer pump. So I could just leave all valves open and if and when I get an imbalance, I could transfer fuel. But it just seems to be kind of a waste to have to always be transfering. I wish I could just burn and return to the tank I want.

 

[OldDan1943]

Steve, I have a similar problem with the AT34. It returns only to the port tank. I hope to correct this over site by the fuel polishing system or drill a hole high in the starboard tank, adding a valve and hose to select a tank to return.
I run the 2 tanks cross connected so, in theory the fuel level will remain constant.
Running cross connected IMO, is not a smart idea.... fuel contamination possibility but sometimes we just need to live with a bad idea.

 

[rolomart3]

Just one more point. According to my experience with the Lehman 120 and indications in its manual, the injection pump is not self priming.

 

[Comodave]

He does not have a 120. He has 225s.

 

[FF]

"One thing on my list now is to install a return line from one side to the other."

The better technique is a genuine ganged fuel valve that has the ability to switch both the fuel supply and return . No thinking , no problems.