Diesel Re-Plumb

[jamieFL]

Hi. I've been working on my boat and haven't started the Yanmar 1gm10 in quite a while. When it was started often, it cranks right up. It has been several months and after several minutes of cranking, it won't start, and then the fuel priming bulb sprung a leak. My fuel plumbing is circa 1988, so be for I blead the lines, I'm gonna replace them all.

My fuel hose goes from the tank, below the motor level to a fuel bulb. From there it goes above injector pump level to the water separator filter. The it loops down, goes through a cutoff valve, then below the lift pump, and back up. There it is stock yanmar to the filter, then injector. The return line sags down before returning to the top of the tank, which is above the engine.

My question is that the whole system, being old, is also very messy. I read that the travel of the hoses is important to properly blead the lines...hose dips and crests need to be planned. Also, I saw a diagram that recommended a one way valve on the return line, which I don't currently have. I am going secure the lines when done. Any advice before I get started will be appreciated

jamie

 

[FastOlson]

I have owned a diesel boat since 1994, and helped friends with their engine questions. I have *never* heard of a need for a check valve on a fuel return line. However, that does not mean that someone else is not happy with having one!
As for the flow.... we have a quarter-turn valve right at the tank outlet, bottom of the side on the low end--
Then the hose, almost arriving at the engine compartment, goes to a Racor 500 filter, then to a 12 volt lift pump, then to the spin-on factory filter on the engine, and thence to the high pressure pump.
The return line parallels the supply line, back to the tank to an inlet fitting at the top.

In general, when your hoses get to their 20th year anniversary, best to have a small celebration with chocolate chip cookies and a libation... and replace all of them. Do all the engine coolant hoses while you are in the mood to party.
Whether used a lot of a little, all these parts degrade with time.

 

[Claude L.-Auger]

I'm with Fast Olson as to the need of a check valve on the return line. Have had diesel engines since the early 90s and never seen one. Consider the fact that the fuel in the return line is pushed by the engine. That is excess fuel returning to the tank and being dropped in it. There is no way the fuel can get siphoned back to the injectors. But it's your boat hence your decision. Also with him on the idea of replacing all lines, including the return. A suggestion if you want to get the engine started before you tackle line replacement: get a clean jerrycan filled with clean diesel fuel and run a hose with a bulb to your fuel pump. when you're sure you've got only fuel getting at the pump, start the engine. It should kick on right away.

 

[jamieFL]

Olson,

Thanks. I've already redone all the coolant lines. Boy was that expensive. I still need to replace the large exhaust hose as it is in pretty bad shape. I also need to replace the supply and vent hose to the diesel tank.

But before that, I want to replace the fuel lines so I can get the engine running again.

jamie

 

[jssailem]

Do all the engine coolant hoses while you are in the mood to party.

I am doing the coolant hoses and the heat exchanger (helped - motivated by my buddy @LeslieTroyer he loves to disable my boat - to do good) in the radiator shop as we speak. The fuel lines appear to be fine... No drips no engine fuel issues.
Party On!

 

[Benny17441]

Fuel pump capacity and the diameter of the lines will insure adequate pressure in most line routing configurations. Worry more about clogged fuel filters, air in the lines and fouled or bad fuel. Sounds to me like you may have a small air leak that when the engine sits for a long time air gets into the lines disrupting fuel flow. Depending on the location of that priming bulb that rupture may be where the air is getting in. Replacing the filters is recommended, go ahead and bleed the system and get the engine started, observe any fuel leaks especially at the connections as where fuel leaks out when the engine is running air will leak in when the engine is stopped. The bleed screws themselves are susceptible to leaks.

 

[jssailem]

priming bulb

Generally, a priming bulb is a poor choice for a pump assist in a diesel fuel system. They are a known leak hazzard in a fuel system. Used often on an outboard motor portable fuel tank they are a great way to get gas on your hand when starting the motor. In such use it is easy and constantly monitored. Repair or replacement is done when they leak. As a permanent fixture in a diesel system much better to get a manual lever pump as a part of your fuel filter or add a continuous use electric pump to your system.

 

[jamieFL]

The rest of my order is arriving today, so I'll be tackling this job this afternoon. The weather is beautiful today and it will be a good day to do it. I already bought the primer bulb, so I think I'm going to use it. I don't see an advantage of a 12 volt pump on this boat. Also gonna skip the one way valve as advised.

I hope I can get it bled and running too.

 

[Stu Jackson]

a priming bulb is a poor choice for a pump assist in a diesel fuel system.

Absolutely. John's right.

Here's why:

Hall of FAIL - Marine How To

Proper Wire Is A Must This is not a joke. Rubber jacketed wire was used in place of proper marine rated & jacketed wire. All wire is not created equal... NOTE: Click on any image to make it larger

marinehowto.com

 

[jamieFL]

I think I found the leak. The banjo bolt on the low pressure side of the fuel lift pump was a little loose, alowing the hose barb to spin. Also, the PO used 3/8 in fuel line and all the hose barbs are 1/4 in.

It was getting dark when I started, so I'll bleed the lines and get her started tomorrow. I used the fuel bulb since I already had it. I'm not interested in an electric pump. Did someone mention a lever pump? Can someone give me a link?

 

[LeslieTroyer]

I think I found the leak. The banjo bolt on the low pressure side of the fuel lift pump was a little loose, alowing the hose barb to spin. Also, the PO used 3/8 in fuel line and all the hose barbs are 1/4 in.

It was getting dark when I started, so I'll bleed the lines and get her started tomorrow. I used the fuel bulb since I already had it. I'm not interested in an electric pump. Did someone mention a lever pump? Can someone give me a link?

Electric lift pumps can be had for about $20. Install a bypass valve at the engine on fuel inlet and return. Changing filters gets super easy. As a plus I leave mine open a crack and any air from upstream makes its way into the return line.

 

[LeslieTroyer]

I am doing the coolant hoses and the heat exchanger (helped - motivated by my buddy @LeslieTroyer he loves to disable my boat - to do good) in the radiator shop as we speak. The fuel lines appear to be fine... No drips no engine fuel issues.
Party On!

John if you didn’t have someone pushing you would still have a heat exchanger that you’ve never/couldn’t changed the zinc on.
On a fuel line related note Johns fuel lines are interesting as they are all threaded fittings, same fittings on external oil lines and propane hoses.

 

[jamieFL]

Electric lift pumps can be had for about $20. Install a bypass valve at the engine on fuel inlet and return. Changing filters gets super easy. As a plus I leave mine open a crack and any air from upstream makes its way into the return line.

I'm not worried about the cost, but that if a leak develops, the electric pump will spray diesel into the bilge. Also, a pump will require another electrical circuit and be another drain on the batteries. I guess I'm not seeing how it is any better since my engine doesn't require one.

My old fuel bulb did crack while I was trying to prime the engine, and it did leak while waiting for a new one, so I see your point. I've spent a little time looking for an alternative and not really found one. So if my only choice is electric or a fuel bulb, why can't a fuel bulb work safely and is electric really better and how?

 

[Stu Jackson]

why can't a fuel bulb work safely

Didn't you read the link in my reply #9?

be another drain on the batteries

Nonsense, your engine will be running when it's on!

a pump will require another electrical circuit

Nope, not another circuit, just run it off your ignition switch ON post. It's just wiring.

 

[FastOlson]

Stu and Leslie.... good advice gained from years of experience....
The veritable "Dynamic Duo" !!

 

[Alan Gomes]

I just completely redid the fuel system on my 1GM and will be putting together a blog post (with pictures) on the Ericson (EYO) site once I get a chance. Following the design of my friend Neil Dutton and based on some suggestions from Guy Stevens (on the EYO list) this is what I did:

I disconnected the on-engine mechanical lift pump and removed the small on-engine fuel filter altogether, including the metal lines that ran to the lift pump and to the injection pump. The lift pump is still attached to the engine but both lines are unhooked so the pump does nothing. (No need to cap off the in/out ports of the lift pump; just disconnect both lines.) The function of the mechanical lift pump is now handled by a Facet electric pump. I put a banjo barb fitting on the injection pump so that I could plumb directly to it from my large Racor 500 filter. I also installed a diverter valve so that I send the fuel either to the injection pump or into the fuel return line for priming the large Racor and/or polishing the fuel in the tank if I wanted to. I also have a SPDT switch that allows me to energize the pump from inside the engine compartment without the ignition switch on. I used new 1/4" ID fuel hose and hose clamps throughout.

So here is the direction of the flow, starting at the tank:
(1) Tank
(2) Input side of the Racor 500
(3) Output of Racor 500 to input of the Facet electric pump
(4) Output of the Facet electric pump to the center input of the diverter valve.
(5) One side of the diverter valve output goes directly to the injection pump
(6) Other side of the diverter valve output is teed into the fuel return line.

This works fabulously.

To prime the empty Racor, I set the diverter valve to output fuel into the fuel return line. I throw the switch and listen to the sound of the pump, which changes noticeably when the Racor fills with fuel. Run for a short time beyond that (just for good measure) and the filter is primed. Then, I switch the diverter valve to send the fuel to the injection pump. With it under pressure from the pump, I crack the bleed screw at the injection pump until solid fuel comes out. Then I tighten the bleed screw (while still under pressure) and then put the switch in the position for normal operation, i.e., to get its power from engine panel.

As for the on-engine lift pump, you do not need to remove it; simply disconnect it. Or, if for some reason it bothers you having it on there, you could remove it and fashion a plate to cover it. Those pumps are bad news because if/when the diaphram fails it dumps diesel into your crankcase. Also, the priming lever on it is a complete joke.

Definitely lose the primer bulb, no matter what else you do.

Here is the barb you need for the injection pump: Fitting Adapter 1/4" Hose ID Barb x 12mm or 7/16" Banjo Steel Zinc plated #DG | eBay

And this is the electric pump I used: Amazon.com: Facet-Purolator Fep60sv GOLD-FLO Fuel Pump: Automotive

And the diverter valve: FUEL VALVE SHUT OFF FUEL TANK 1/4" THREAD 18-1655 3 WAY VALVE WITH DETENT BRASS | eBay

Hope this helps.

 

[jamieFL]

Thanks everyone. For now, since I have it, I'll use the bulb, but before I put the boat in the water, I'll look into a system like the one @Alan Gomes has. As a precaution, the bulb is mounted above the tank so there is no risk of diesel sifening out of the tank if the bulb splits in the mean time.

Didn't get it started.. Turns out I didn't bleed it properly. Will give it another try on my next day off.

 

[sailme88]

With ALL of the bantering about the fuel system, it appears that a very important aspect of the initial post was overlooked. Jamie FL indicated that the engine had been idle for some time and that several minutes of cranking occurred. It should be the practice of Diesel engine owners that when attempting to start such an engine as described, that the water line to the engine be kept shut so as to not draw an excess of water into the engine that a lack of exhaust can not get rid of. Once started, the water can be immediately opened.

 

[jamieFL]

@sailme88, thank you. I'm good here.