Fuel Puzzle

[DBoss]

I recently purchased a 2001 310 that had been under a little neglect. I spent a hefty $5K after purchasing the boat to have a mechanic go over the engine and do a full service, replace a bunch of parts and give it a clean bill of health. Last week while out cruising I had a situation where my diesel engine sputtered and stalled and appeared to be starving for fuel. I could get the engine to start but could apply no load without it dying. My fuel gauge was at 50% so my first thought was plugged fuel filter. They looked okay but I swapped them both out anyway, bled the system and restarted. Same situation, seemed to be starving for fuel and could not put on a load. I could hear the fuel pup kicking in so my next thought was maybe the fuel gauge is off and I ran the tank dry. I topped up my tank with about 16 gallons of fuel and had another attempt. It started off struggling but I let it urn for a while and eventually settled down. No issues and all seems great. I should have had 10 gallons of fuel left so should not have run dry. My only theory is that the fuel pump is dying and needed the extra head from the full tank to help with flow but that also seems flawed as the problem did not build gradually and came on suddenly. It really seemed like I had air in the system but that shouldn't have happened either if the tank still level was still good.

Question is, does anyone know what the dip tubes that draw the fuel out of the tank are made out of? I am wondering if they might draw air in at a certain point when the tank level gets low. I am still puzzling over what the original cause was.

 

[Stu Jackson]

Also consider this if you have a Racor 220 filter housing:

Fuel Starvation and The Obscure Check Ball Valve

Fuel Starvation and The Obscure Ball Check Valve

 

[DBoss]

Also consider this if you have a Racor 220 filter housing:

Fuel Starvation and The Obscure Check Ball Valve

Fuel Starvation and The Obscure Ball Check Valve

A good tip, I was not aware of this and will definitely check it out.

 

[kloudie1]

Two other things; a plugged tank vent or some pickup tubes have a wire gauze on the tip that can plug.
If it does that again, open the fuel fill and listen for a hiss. If ya hear that and it restarts, plugged vent is the problem.

 

[SawyerCurt]

...my diesel engine sputtered and stalled and appeared to be starving for fuel.

See my post here about a connection issue that was shutting off the fuel pump.

 

[DBoss]

Thanks all for the great tips, very useful information.

 

[cloydmilton]

My engine died due to a plugged pick up tube. The tube had a screen plugged by algae growing in the tank

 

[bulbcreekfarm]

Apparently 1/2 tank and below gravity is no longer helping feed the engine with fuel. There are some connections with the fuel pump i've read on here that are finicky (shovel connectors on the engine) that you can check but if you say you hear it pumping I would assume you might have a clog somehwere in one of the lines or the pump is dying

 

[Tom J]

Apparently 1/2 tank and below gravity is no longer helping feed the engine with fuel. There are some connections with the fuel pump i've read on here that are finicky (shovel connectors on the engine) that you can check but if you say you hear it pumping I would assume you might have a clog somehwere in one of the lines or the pump is dying

The C310 is unusual in that the fuel tank is mounted somewhat above the level of the engine. Even if the lift pump is not operating, the engine will usually run until the tank is about half full.

 

[DBoss]

Folks, thanks for all the great comments. The engine seems to be running okay now with a full fuel tank. The ball check valve was gunked up so I cleaned that out as well. I have a new fuel pump on order so will swap that out when it arrives just to be safe. I am still not sure what the actual issue was (or is) but I am going with a combination of low fuel level, gunk in the ball valve and maybe a tired fuel pump. Good to know about the screen in the pick up tube. I have not pulled that out yet but think I will when I swap out the fuel pump.

 

[Hollyberry]

A friend had similar symptoms a while ago on a Hunter 40. Eventually found the pickup tube had a pinhole a couple of inches below the top of the tank. Ran fine when full but once the pinhole was exposed they were sucking air (which symptoms match yours).
Might be worth looking at that, esp if the problem comes back at lower fuel tank levels.

 

[Deleted member 117556]

I operated my 310 for About 7 years without a functioning lift pump. Didn’t realize it wasn't functioning until I went to replace it. Suspected something because it was impossible to bleed air out using the lift pump and bleed screw. Despite that I never actually had to bleed air out after changing fuel filters and never had any engine troubles. Have a new lift pump now but can't notice any difference.

 

[AllenC57]

To answer your question, I believe the fuel lift tube is made of nylon. I had mine out a couple of months ago and that's what it appeared to be. (Some type of plastic tube anyway... don't know if all 310s are the same). I never thought to check for holes in the tube, but that's not a bad idea. I've had so many fuel flow problems it is ridiculous. The symptom is always the same... the engine will loose RPMs and just not run above a certain RPM. I've installed inspection ports in the tank, and cleaned it out. I've done basically all of the things mentioned anywhere about fuel flow on this forum. I'll add one more thing that got me:

The handle to the fuel shut off valve on the tank stripped out such that when I was thinking it was open (as indicated by the handle position) the actual ball valve was barely open (maybe 1/4 way open). It was also clogged with gunk. (Fixing this solved most of my problems).

We started out our last 90 day cruise from down the west coast of Florida to the Keys with a clean tank, clean fuel and fresh filters. Everything was good until we got some dirty fuel along the way. Started having problems maintaining RPMs as we were going through draw bridges in the ICW (stressful with currents and a poor running engine). Replaced fuel filters and everything was good for about another 100 hours then had to replace them again after a gulf crossing. Just enough fine silt in the primary filter to snub the flow of fuel.

I broke the golden rule: "only purchase diesel from high volume marinas." The bad fuel we got was from a yacht club that probably didn't sell that much fuel (Stupid me! It was just convenient).

Good luck... try to sail as much as possible! We motored way more than I anticipated on our 3 month cruise, but had a great time.

 

[2 OLD PIRATES]

I had the same thing happen to me and I found out that the clamps on the fuel line where loose and allowing air to seep in. As soon as I tightened them up it work as it should. The original lines got soft and so the clamps where loose.

 

[ed canty]

I just went through this. If your oil pressure alarm doesn’t sound when you turn the ignition on (before you start) it could be the alarm ground on the fuel lifter. I had the same symptoms. Once the fuel got lower in the tank it became noticable with loss of power and ultimate stalling. Once I cleaned up the corrosion on the negative connector (which was a pain to clean), both the alarm and fuel lifter started working again. Of course it could be 10 other things as well.

 

[Project_Mayhem]

Would it be reasonably possible to test for leaks in the fuel system with a vacuum gauge if one were to block off the tank vent?