Genset running out of fuel

[MyPleasure]

Hey fellas, thanks for all the advice on this. I think that I might have figured out what the problem is. I think the main problem is that whoever installed the generator tied into the fuel lines from the main engines instead of a dedicated generator fuel supply on the fuel tanks.
What I’ve found is, when the generator has been running for anywhere from 10-30 minutes, it runs out of fuel. If I start the main engines and run them for maybe 2 minutes, the generator has fuel again and runs fine. So the problem must be with the way that the installers tapped into the main engine fuel lines. I don’t know if the generator was a factory installation or not, so I don’t know who to blame for this one. Luckily, there seems to be plenty of fuel in the lines to start the main engines after the generator stalls.
Sometimes the generator will run for several runs before running out of fuel. I haven’t heard from anyone with a similar installation, so maybe ours is a one off, not sure. This winter I’ll do more investigation into the fuel lines, but for now, we can make it work for the rest of the summer.

[km1125]

It's possible the lift pump on the generator does not have enough suction to overcome the anti-siphon valves, but your main engines can.

Did you already check, replace or otherwise rule that out as Waybomb suggested in post #2?

[MyPleasure]

Hi km1125, not sure where the anti-siphon valve is located to tell you the truth. It certainly does sound like that could be a problem.

[km1125]

The anti-siphon valves are located right at the fuel tank pickup. Looks like an longer adapter from hose barb to pipe thread. You can search the internet for some images then look at your boat for something that matches.

You can remove them and clean then, or just replace them. They are not very expensive (~20/ea?) They are often a source of trouble on older boats when fuel delivery is diagnosed as the issue.

[bud37]

If you can , post some pics of the fuel line and valving set up you have .....perhaps someone will spot something.

[MyPleasure]

Thanks guys, I will check the anti-siphon valves tomorrows. I know that there are all kinds of interference in the way of the tank tops, wireways, fuel lines, etc., but I will definitely check the valves out. I’ll try and post pictures of the fuel tank selector valves as well.

[MyPleasure]

I did check all four anti siphon valves, which my back is paying for today, and they’re all clean and seem to be operating correctly. Someone replaced one of the brass anti siphon valves for an aluminum one, but I’ll pick up another brass valve to replace it. I checked the port fuel tank breather, and it’s clear and working. I must admit, the fuel tank breathers seem a bit small, I would prefer the breather hose be more like 3/4” rather than the 3/8” breather hose currently used.
We’ll head out on the boat next week and see how the genset runs.
Thanks again for all the advice fellas!

[MyPleasure]

I’m still having trouble downloading pictures to this website for some reason. Is there a trick that I’m missing?

[MyPleasure]

Would it be possible for someone to walk me through how to download pictures to my posts?
Thanks

[bud37]

If the pics are too large I email them to the lap top then download to the desktop and upload from there....that way the pics are sized better for here.

A question , do you have an inline fuel filter like a Racor in your gen fuel line and have you eliminated the gen fuel pump as an issue ?

Also cutting into a line sometimes works better from a flow perspective if the split is a "y" used instead of a "t". I still say It is far better for each end use to have it's own dedicated fuel line, no in fighting....kinda like the kids...