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Old 02-09-2019, 11:18 AM   #81
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Originally Posted by Wxx3 View Post
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?
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Old 02-09-2019, 07:11 PM   #82
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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...).
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Old 02-09-2019, 08:18 PM   #83
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Originally Posted by RT Firefly View Post
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.
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Old 02-10-2019, 02:43 AM   #84
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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,
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Old 02-10-2019, 10:12 AM   #85
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Originally Posted by rolomart3 View Post
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 youíll 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 wasnít starting though, even though the injection pump on the Lehmanís 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.
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Old 02-10-2019, 10:24 AM   #86
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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 Iím running, say 2 hours, all valves open, Iíll get an inballance within 30 minute because Iím sure one tank is slightly more restrictive than the other. So Iíve started just pulling off of one tank or the other. But since one engine is always going to basically be transfering via fuel return, Iíll get an imbalance quickly as well. So even though Iím only burning about 4 gph, Iím moving a lot of fuel around. And it doesnít 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.
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Old 02-10-2019, 11:24 AM   #87
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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.
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Old 02-10-2019, 03:04 PM   #88
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Just one more point. According to my experience with the Lehman 120 and indications in its manual, the injection pump is not self priming.
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Old 02-10-2019, 03:10 PM   #89
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He does not have a 120. He has 225s.
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Old 02-12-2019, 06:29 AM   #90
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"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.
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Old 02-12-2019, 06:57 AM   #91
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"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.
A. Tank isolations valves.
B. cross connect valve to keep the fuel levels equal, shutting this valve when there is contaminated fuel in one tank
C. a fuel return valve from each engine and generator to both tank you wish. Will help with trimming the boat. If it was necessary to isolate a tank due to contaminated fuel, you want to be able to return the clean fuel to the supply tank.

Of course we did not install the valves necessary for the fuel polishing system.


I think that does it.
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Old 02-12-2019, 02:58 PM   #92
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I didn't read every post here, but Ill just add that I recently went through fixing an air leak in my fuel system. The number one thing I added to my fuel system is a squeeze bulb placed motor side of the racor. It allows you to bleed a completely dry system all the way to the injector pump in about 5 minutes total for both motors. No electrical needed, no more messing with the lift pump lever in frustration ext.. I no longer worry about changing the Sims filters on the motors, or replacing/inspecting fuel lines - its easy now.
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Old 02-12-2019, 03:09 PM   #93
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I didn't read every post here, but Ill just add that I recently went through fixing an air leak in my fuel system. The number one thing I added to my fuel system is a squeeze bulb placed motor side of the racor. It allows you to bleed a completely dry system all the way to the injector pump in about 5 minutes total for both motors. No electrical needed, no more messing with the lift pump lever in frustration ext.. I no longer worry about changing the Sims filters on the motors, or replacing/inspecting fuel lines - its easy now.
Is the squeeze bulb in the primary fuel line or do you redirect the fuel with valves when the bulb is needed? (Ie is fuel flowing through it all of the time?)
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Old 02-12-2019, 03:18 PM   #94
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Yes its in the primary lines one each after the racor. I'm using the good ones about $12 each. I have researched and followed up with ABYC surveyors and a friend that's in the guard. I'm told they are fine for use with diesel below deck but NOT for gas. One of the surveyors I spoke with also has them on his boat. There's tons of controversy on the topic, but for me its more of a safety issue NOT having them. Use at own risk like everything else..
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Old 02-13-2019, 07:42 AM   #95
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A second advantage of a fuel bulb from the tank feed is searching out air leaks.

With a bit of pressure fittings and gaskets that might leak are easily found by using a strip of paper towel tied to every fitting and component.

If there are no fuel leaks in 24 hours , the system is probably air tight.
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Old 02-13-2019, 12:37 PM   #96
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A cheesy rubber bulb, in-line with the main fuel system that contains hundreds of gallons...what could possibly go wrong?

Isolate it in a loop with two valves and select it when you need it, just like a sight tube. Same with an electric pump.
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Old 02-13-2019, 02:36 PM   #97
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I agree that I would isolate the bulb. My tanks would gravity drain most if not all of the fuel if the bulb broke.
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Old 02-13-2019, 03:02 PM   #98
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“If the bulb broke”

Not being argumentative however is there any more probability of having the bulb break vs having a fuel line rupture? If the bulb is good quality CG approved material like the CG approved fuel line, logic would tell me probably not? I agree that having a bulb in line still feels a little awkward.
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Old 02-13-2019, 03:02 PM   #99
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Interesting post.
The first thing I would be inclined do is to fit a shut off valve at the tank with non return valve directly on to it, because between the tank and filter is a long line and you have to build sufficient vacuum to lift the fuel, if you stop to pump the fuel will run back.
If using CAV sandwich type filters I would fit the modified filter head with 'spin on' filters incorporating a 'heel of the hand' button pump.
Bleeding the engine is child's play then, simply put fuel in the tank and pump until the button goes stiff, then slacken ALL injectors lines, open the throttle full, and crank the motor.
If you have crew get them to pump the button pump while your cranking the motor but be ready to close the injector lines and throttle pdq when she starts to fire.
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Old 02-14-2019, 06:25 AM   #100
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"I agree that I would isolate the bulb. My tanks would gravity drain most if not all of the fuel if the bulb broke."

On some boats the fuel supply line is taken from the top of the tank which may be higher than the engine.

So a leak in the fuel system could syphon the tank empty.
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