Fuel tank pickup problem

[Scott21120]

Sunday we took some friends out on our Oday 34 - 15 kts of wind, but 3'-4' choppy waves like we often get on Lake Michigan. Coming back in, we sailed into the harbor, started the engine and dropped the sails. Just as we rounded the entrance into the mooring field, then engine - which I thought had been dropping rpms slightly - petered out completely. Fortunately the wind was still blowing, and we unfurled the jib and sailed to the mooring. I recalled a conversation with the previous owner in which he told me that when the boat has 1/4 tank of fuel or less, and you get into chop, the fuel pickup will suck air. I honestly didn't realize I was down to 1/4 tank - I knew it was getting close - but the engine is SO reliable, I had forgotten the previous owner's warning. I bled the system and put a few more gallons in, even though we are close to haulout time. I would like to pull the tank over the winter to have it cleaned and also inspect the fuel pickup situation. Does it sound normal for the pickup to suck air at 1/4 tank? I wouldn't really plan on running the tank down much closer to emtpy anyway - most of our motoring is in and out of the harbor, but if there is a larger problem, like the pickup rusting away or something I would like to take care of it.

 

[Rick I]

Doesn't sound right

it might be that the pick up tube has a hole in it or that the tank is a bit cruddy and the shaking up resulted in dirty fuel. If you've checked your racor and other filters and they are ok it's probably air. I went through the cruddy fuel scenario until I pulled the tank and cleaned it. Every time I went out when it was exceptionally lumpy my engine would start acting up, finally pulled the tank and took it to a rad shop where they cleaned it all out.

 

[Rich]

fuel tank finding air

It sounds likely that your situation was caused by the combination of 1/4 tank fuel and choppy seas. I had a similar experience with about 1/2 tank of fuel , motor sailing and heeled at about 30 degrees. Most small fuel tanks, mine is 11.5 gals., don't have baffles. Therefore if the boat is heeled at an angle , so is the fuel and if, as in my situation, the fuel pick up is positioned on the "high side" it may not be sitting in fuel and therefore will suck up air. I simply keep my tank topped off which has rectified the problem.

 

[Paul Akers]

I Would Have the Same Concern...

...as Rick I. Lumpy seas and a tank sediment may be clogging the intake (or the filters) as it gets stirred up. What do the filters look like?

 

[tom]

Started Motor in Harbor

If you started the motor in the harbor isn't it safe to assume that the water was fairly flat??? I can understand sucking air heeled over in lumpy seas but with the sails down and in the harbor???  Shouldn't the pickup be as close as possible to the center and bottom of the tank??? Suck out any water before it has time to grow something. Having several inches of water sloshing around in the bottom of a tank can't be good.

 

[tom]

Started Motor in Harbor

If you started the motor in the harbor isn't it safe to assume that the water was fairly flat??? I can understand sucking air heeled over in lumpy seas but with the sails down and in the harbor???  Shouldn't the pickup be as close as possible to the center and bottom of the tank??? Suck out any water before it has time to grow something. Having several inches of water sloshing around in the bottom of a tank can't be good.

 

[Stu Jackson]

Has the screen at the end of the pickup tube been

removed?

 

[Scott21120]

Some clarifications

Stu, I don't know what's on the bottom of the pickup tube - I will be taking it out in a couple of weeks and will find out then. Tom - when we started the engine, the water was calm (in the harbor) but we had motored out a couple hours earlier into some chop for about 10-15 minutes. I wondered if it got some air in the lines then that just made it's way to the injector pump when we restarted it later. The primary filter with the clear sediment bowl is very clean. I just replaced both filters less than 15 hours ago. I have motored in some reasonably serious chop previously (always with more fuel in the tank) and never had a problem. When I changed the filters at about 100 hours there was a very fine layer of sediment laying on the bottom of the filter bowl. Someone else told me that generally air will make the engine rev a little higher then die, my symptoms were that over about a minute the rpms gradually (almost imperceptibly) lowered, until I realized I wasn't getting much power - increased the throttle and then it died. It did start again, but died right away. I did not try starting it at the mooring, just turned the key to energize the electric fuel pump and opened the injector pump bleed screw. I did get a burst of air before fuel began flowing again. The previous owner had been using Bioguard and I added it to this tank of fuel as well.

 

[Anchor Down]

Think About it, Scott

All your filters and screens get changed regularly, except one: at the end of the pick-up tube at the bottom of the tank.My bet is that it's fuel starvation caused by that clogged screen. Happened to me, and I tore every filter and pump apart. Unfortuantely, it was the last place I looked, instead of the first.Which is easier to believe: that somehow holes developed in the pick-up tube (what would be the mechanism to create them?), or a screen clogged with X years of dirt?Check the simple things first. This is very simple.

 

[s sauer]

Fuel pick-up Filter Screen

How do you get to the pick-up to check it? I have a poly tank and a fuel outlet fitting with a shut-off plus a surface mounted gauge that does not seem to even have an opening into the tank.The only way I can 'clean' my tank is to pump out all the fuel and see what comes out in the last gallon if there is any dirt or water. So far there isn't any water or more than 2-3 specs of dirt when I drainout 8 oz from the Raycor 220 filter.

 

[Stu Jackson]

The fuel pickup hose has to go into the tank

somewhere. Only you can figure out how and where it goes in and how to get it out, because it HAS to come out since a human (hopefully) put it IN to begin with.