Priming fuel bulb inside engine compartment

jviss · Aug 3, 2023

What's inefficient about the lift pump method? Wondering; I assume by lift pump you mean the electric fuel pump, not the on-engine low pressure pump. I just attach a remote started switch to my electric pump so I can activate it while sitting at the engine when bleeding; though, bleeding has only rarely been necessary, with the built in hand pump on my Racor.

capta · Aug 3, 2023

I put mine above the tank in the salon hatch to ensure it didn't get too how. Lasted 6+ years. It did mean it was a two person operation, but that worked for my wife and I. It also facilitated getting fuel easily, as I added a spigot in the engine room.
I heartily recommend the priming bulb (though Mainesail does not), if not directly at the tank somewhere convenient, outside the engine compartment.

dlochner · Aug 3, 2023

How hard is it to pump diesel a few feet through a 5/16" hose? How often is it necessary to bleed the fuel system?

If the filter is below the fuel level in the tank, it only necessary to start a siphon to fill the filter and then it is only a few feet through small diameter hose to the high pressure pump.

jssailem · Aug 3, 2023

There are options in all projects.
What would cause you to prime the engine?

If I change the engine fuel filter I have to prime my engine.
If I run dry I have to prime the engine
If the filter gets clogged I have to prime the engine

There are 3 events that I have experienced. The time to use the manual lift pump took in these events took from 10 to 30 minutes. Depending on where your fuel tanks are located it is a simple or a bugger of a task. An electric fuel pump is a valuable option.

Sure you can get a manual bulb. It can be located in a safe space but eventually it will fail. Diesel will either leak all over you hands or worse. Then your left with no pump and a severed fuel line.

If this is important then get a good electric pump. Walbro makes excellent pumps.

While you’re at it why not create a fuel polishing capability. Some plumbing parts can create a manifold allowing you to move fuel through your Racor and back to the tank.

If this interests you and you want an elegant solution, send me a PM.

Alan Gomes · Aug 3, 2023

This is how I have my Yanmar 1GM set up (see attached). I don't really use it for fuel polishing--though I suppose I could. It's primary purpose is to deal with what is being discussed in this thread: priming the Racor fuel filter and bleeding the system of air.

This system is really fantastic. I have a toggle switch in the engine compartment that runs the electric fuel pump without having to energize the engine panel. With the valve set in the priming (polishing) position, it fills my large Racor 500 lickety split. Then, when I set the valve to send the fuel to the injector pump, I can crack the bleed points and get any lingering air out of the system.

Another advantage of this system is that you no longer are using Yanmar's mechanical lift pump. If/when the diaphragm fails on that pump, its failure mode is to dump fuel into the crankcase! No bueno. You can still leave the mechanical pump on the engine; you simply disconnect it. It doesn't hurt a thing to leave it installed. Or, if you prefer, you could remove the pump and fabricate a cover plate to cap the hole.

Benny17441 · Aug 3, 2023

Nothing wrong with the mechanical lift pump method to bleed air from the fuel lines. If done properly a little work will insure good results. A manual bulb pump made of rubber should not even be considered unless used in a portable auxiliary can for emergency. An electrical fuel pump takes away the diesel engine capability to run without the need for electricity. Simplicity is the heart of the engine's reliability, start adding things and the chances for things to fail increase besides the addition to the factors of diagnosis.

Alan Gomes · Aug 3, 2023

Benny17441 said:
Nothing wrong with the mechanical lift pump method to bleed air from the fuel lines. If done properly a little work will insure good results. A manual bulb pump made of rubber should not even be considered unless used in a portable auxiliary can for emergency. An electrical fuel pump takes away the diesel engine capability to run without the need for electricity. Simplicity is the heart of the engine's reliability, start adding things and the chances for things to fail increase besides the addition to the factors of diagnosis.

Many diesel engines already use electric fuel pumps. My previous M25XP did. And they are highly reliable. Plus, if they do fail at least they don’t run the risk of dumping fuel into your crankcase.

In the mod I suggested there’s no reason you can’t leave the mechanical pump on the engine but disconnected. It could be there if one wanted to hook it back up for some reason.

Trying to prime an empty filter with that little thumb priming lever is purgatory. Good luck doing that in a seaway, as sometimes happens with filter clogs. With a Racor 500 and the system shown in the PDF, I could swap filters and prime the engine in minutes without spilling a drop, even on a pitching boat.

Maine Sail · Aug 6, 2023

skunther said:
Manual lift pump seems pretty fickle on my 3GM.

On Yanmar engines, the manual pump just needs the crank rotated a bit until it feels like it’s working.

I don’t know a single priming bulb rated for below deck use. years ago I had a trawler customers below deck bulb fail. it totaled the boat.. I posted an image of it here ..

Benny17441 · Aug 6, 2023

Fill the filter bowl with fuel before installing. Gravity should lead fuel to the lift pump so give the engine starter a few cranks . Open the bleed screw and take over with the lift pump lever to expel enough air to get the engine started. With the engine running open the bleed screws gradually to bleed off any remaining trapped air. Clean up any excess fuel that may have spilled.

gettinthere · Aug 30, 2023

I have a walbro electric pump in line. it has plenty of head lift capability to pull fuel up from the bottom of the tank.

dlochner · Aug 30, 2023

skunther said:
@Benny17441 my engine seems relatively smooth but is shaking too much to bleed the screws when running. The change ended up being easy though. The diesel in the old element was contaminated so I disposed of it. I used the integrated pump to bleed the primary, then once that was clear of air, I simply started the engine. I don’t believe any air was in the system after bleeding the primary, as the lines descend from it and gravity keeps fuel in them and prevents air from entering.

If the engine is running, it isn't necessary to bleed the lines because fuel is getting to the cylinders. Any residual air in the line will work its way out.

Project_Mayhem · Sep 5, 2023

I have an electric fuel pump installed by a previous owner. I have it connected to the choke terminal on the key/ignition switch. Push the key in to prime, start engine, fuel continues to flow through the pump when the pump no longer has power applied to it. The engine's own pump takes over once it's started

Dalliance · Sep 7, 2023

This seems to be a recurring topic. My response to related question last spring seems relevant. In short: No to bulbs, add an isolation valve, try suction. Rather than rewriting the whole post, I’ve attached a link. See Post #9.

Yanmar 2GM20F Fuel Lines, High or Low pressure?

Every year I try to go through some of the maintenance on our 88 Hunter 28.5 & the 2GM20F engine. This year, I drained out all the diesel fuel in the tank and cleaned it out (brush on a long flexible rod, & vacuumed out the inside). I also used a USB portable camera with LED lights, to...

forums.sailboatowners.com

Dalliance · Sep 19, 2023

skunther said:
I hadn’t thought of that. I don’t see how I’d attach the oil extractor to the bleed valve screw though. Does your bleed screw have a bead attachment on top? Do you happen to have a picture of your setup?

Not the ideal photo angle, but all I had on hand. It’s the air accumulator screw at the red arrow. I take it out completely and just the jam the small suction tube into the opening. Then finish with the screw back in and the manual pump. Just minimizes the hand pumping needed. Note also that I have an in-line shut-off valve right at the inlet side of the primary Racor filter to minimize how much line I have to bleed.
This is the vacuum oil extractor I have.

Manual Oil Changer 2.9 Quart | West Marine

Check out our Manual Oil Changer 2.9 Quart and more from West Marine!

www.westmarine.com

Priming fuel bulb inside engine compartment

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SBO Weather and Forecasting Forum Jim & John

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