Confusion: Fuel Tank and Fuel Pump on Adventure 208

Jonah · Nov 4, 2015

Hello,

I recently purchased a 1996 Adventure 208 with a 2007 e-Tec 175, and I'm having trouble understanding what's going on with my fuel tank, which is 82 gallons. Here's the story:

When I bought the boat, the gauge told me that I had about 3/4 of a tank. My first outing was about 45 minutes at 75% throttle. On my second outing, the fuel gauge told me I had less than 1/4 of a tank, but then when I got on plane, it read closer to 1/2. After 25 minutes at 75% WOT, the engine died. Wouldn't start, no matter how many times I tried it. Even when I added the 5 gallons of gas that I had on board in a storage container. Finally, I remembered to prime the fuel line (by squeezing the little bulb), and then it started right up.

So, I figured that the gauge was off, and I that I had only 5 gallons in the tank now. I went straight home and added about 45 gallons using portable tanks (yes, it was tedious). At that point, the gauge said I had a full tank, but I figured it must be wrong. I then drove straight to a filling station, which took about 25 minutes at 75% WOT. When I got there, I could only put in 10 gallons before it was full! But 45+10= 55, and I must have burned about 5 gallons getting to the filling station. So really, 45+10–5=50. But remember: I have an 82 gallon tank! Where are these other 30 gallons coming from???

All I can think is that my gauge has been telling the truth all along. I must have really had an almost full tank when I drove to the filling station today, and I must have had about 1/3––1/2 of a tank when it died on the water. But why would the engine die when I had something like 30 gallons in the tank? Why would it not start back up until I primed it?

I have learned that this is not a problem with the 'fuel sending unit', because apparently all those things do is tell the gauge how much gas in in there. Apparently it must be a problem with the fuel pump? I'm new to this, so I'm all ears!

Thanks.

Harpoon · Nov 5, 2015

It sounds to me like your fuel tank sender may be sticking. An older sender may stick until the boat bounced around a little.

Although you may also have an obstruction in your tank pic-up, which caused the engine to stop.

DennisG01 · Nov 5, 2015

You may or may not have two problems going on at the same time. First, physically check the tank. Pull the sender out and physically "dip" the tank (make sure the floor/tank is level). Then you can manually move the sender arm while watching the gauge (you may have to add a ground wire to the sender plate, depending on how it's currently set up). You could also, while the sender is still in the tank, short the pink wire to ground while observing the gauge to check wiring and gauge operation. Key needs to be "on" while doing this, obviously.

With the engine issue, it could be any number of things... clogged pickup, clogged vent, old/deteriorated (inside) hoses, air in the lines, a clog somewhere else along the lines, bad primer bulb, fuel pump(s), injectors... and probably more - that's just off the top of my head.

Captnobs · Nov 5, 2015

My guess is that your engine is fine. I have not opened the gas tank compartment to see if it is even possible but the only explanation I can think of is that your tank is not sitting level. There is probably gas in the tank but your pickup is not getting it all. When you run out of gas, you would probably need to pump the ball to fill up the filter/seperator.

Jonah · Nov 9, 2015

Thanks everyone; this is very helpful. I'll post again if I make any progress in figuring it out.

seasick · Nov 10, 2015

Jonah said:
Hello,

I recently purchased a 1996 Adventure 208 with a 2007 e-Tec 175, and I'm having trouble understanding what's going on with my fuel tank, which is 82 gallons. Here's the story:

When I bought the boat, the gauge told me that I had about 3/4 of a tank. My first outing was about 45 minutes at 75% throttle. On my second outing, the fuel gauge told me I had less than 1/4 of a tank, but then when I got on plane, it read closer to 1/2. After 25 minutes at 75% WOT, the engine died. Wouldn't start, no matter how many times I tried it. Even when I added the 5 gallons of gas that I had on board in a storage container. Finally, I remembered to prime the fuel line (by squeezing the little bulb), and then it started right up.

So, I figured that the gauge was off, and I that I had only 5 gallons in the tank now. I went straight home and added about 45 gallons using portable tanks (yes, it was tedious). At that point, the gauge said I had a full tank, but I figured it must be wrong. I then drove straight to a filling station, which took about 25 minutes at 75% WOT. When I got there, I could only put in 10 gallons before it was full! But 45+10= 55, and I must have burned about 5 gallons getting to the filling station. So really, 45+10–5=50. But remember: I have an 82 gallon tank! Where are these other 30 gallons coming from???

All I can think is that my gauge has been telling the truth all along. I must have really had an almost full tank when I drove to the filling station today, and I must have had about 1/3––1/2 of a tank when it died on the water. But why would the engine die when I had something like 30 gallons in the tank? Why would it not start back up until I primed it?

I have learned that this is not a problem with the 'fuel sending unit', because apparently all those things do is tell the gauge how much gas in in there. Apparently it must be a problem with the fuel pump? I'm new to this, so I'm all ears!

Thanks.

Other than giving false readings, a bad sender won't affect engine operation assuming of course that the tank is not 'empty' I can think of two things that may have happened since the motor died but restarted after priming: You lost prime due to an air leak, the pickup out of the liquid, or a bad pump (probably unlikely). Secondly, there could be water in the tank and at some point you were pumping more water than gas.
The geometry of the 208 tank makes the reading of the gas gauge vary dramatically depending on hull angle. Just yesterday with tho people on board and on plane my gauge indicated more than 3/4 full,but when stopped and both people at the helm, it read one bar ( I will explain what that means later. The point is that you can't use the gauge reading meaningfully without taking into account other factors.

On the Yami digital gauge there are 8 possible bars for fuel level. When the display changes from 2 bars to one bar, you might still have almost 40 gals of fuel even though you would expect only 10 ( 8 bars for 80 gals). When one steady bar changes to one flasing bar, you may have 20 gal of gas left. These readings are only somewhat valid at rest or slow displacement mode, not planing.
When I add gas, the display changes by one bar or a bit more per every 10 gals. Note that the difference between 1/4 tank and 1/2 tank could be only one bar!

The most accurate reading will be with the boat docked and nobody on board

You can't rely on the gauge for an accurate measurement. The at rest display in addition to your known rate of fuel burn and your trip time or distance will allow you to make a good estimate of fuel level. Of course if you had a fuel management gauge, things are better ( assuming you calibrate and reset as needed

).

BobP · Nov 29, 2015

Next time motor sounds like it's going to die, get to the squeeze bulb primer quick and see if it collapsed, if it is then there is a restriction on the boat side of the bulb. On my 204c, had the occasion to pick out a chuck of sealant from the pickup tube that limited motor rpm.

And you can get a new fuel sender. As I recall I think it was WEMA I used as replacements on the Sailfish. Very well made all stainless and sealed. Different design than originals. Many years now in service.

seasick · Nov 29, 2015

I just reread the post and thought I would mention that if the motor wouldn't star until you pumped the primer bulb, you may have a bad lift pump. That are a fairly common maintenance item on the etc 175

Jonah · Nov 30, 2015

Thanks again everyone. I haven't had the problem again, but then I haven't gotten back down to less than 1/2 of a tank. If the problem persists, your input will be very helpful. Thanks!

Jonah · Jul 19, 2016

Hi all,

I seem to be experiencing the same problem again.

After the incident above, I filled her up and stored her for the winter, and then this season I've been using my floscan meter to measure gallons carefully. This past Saturday, with about 40 gallons left (in an 82 gallon tank), it happened again. This time I had no spare fuel on board, and could not get the hand pump to work—it just stayed empty and limp as I squeezed it over and over.

I don't know what to think. It's as if I have two 40-gallon tanks instead of one 82-gallon one, but obviously that's not the case.

Now, just to complicate things, the motor also had a hard time starting one day recently with about 50 gallons left. We had just been out for an hour, and had beached the boat for about two hours. For some reason it wouldn't start until I hand primed it for a minute, but then it ran fine all the way home and for the next two outings.

I don't know enough about how sending units or pumps work to have any good ideas. But why can I only access about half a tank of gas?

Finally, I must admit I have not yet followed any of the advice that you will gave me, above. But before I do that, I wanted to see whether this update my change anyone's advice. Does the fact that this keeps happening at the half-tank mark reveal anything about what the problem might be?

seasick · Jul 19, 2016

Jonah said:
Hi all,

I seem to be experiencing the same problem again.

After the incident above, I filled her up and stored her for the winter, and then this season I've been using my floscan meter to measure gallons carefully. This past Saturday, with about 40 gallons left (in an 82 gallon tank), it happened again. This time I had no spare fuel on board, and could not get the hand pump to work—it just stayed empty and limp as I squeezed it over and over.

I don't know what to think. It's as if I have two 40-gallon tanks instead of one 82-gallon one, but obviously that's not the case.

Now, just to complicate things, the motor also had a hard time starting one day recently with about 50 gallons left. We had just been out for an hour, and had beached the boat for about two hours. For some reason it wouldn't start until I hand primed it for a minute, but then it ran fine all the way home and for the next two outings.

I don't know enough about how sending units or pumps work to have any good ideas. But why can I only access about half a tank of gas?

Finally, I must admit I have not yet followed any of the advice that you will gave me, above. But before I do that, I wanted to see whether this update my change anyone's advice. Does the fact that this keeps happening at the half-tank mark reveal anything about what the problem might be?

Your pickup tube could be broken off or have a hole in it. That is tough to check. i still think that your lift pump could be bad. With more fuel in the tank, the motor has less of a 'distance' to pump up the fuel.
One way to check is when you have the problem, try pumping the primer bulb. If it doesn't get firm, you either have a leak or a bad bulb. However if you add gas and the problem goes away, you very well may have a broken pickup tube. When the fule goes lower, you might be sucking air.

Jonah · Jul 19, 2016

seasick said:
One way to check is when you have the problem, try pumping the primer bulb. If it doesn't get firm, you either have a leak or a bad bulb. However if you add gas and the problem goes away, you very well may have a broken pickup tube. When the fule goes lower, you might be sucking air.

Thanks Seasick,

To confirm: the primer bulb is not filling right now, no matter how many times I squeeze it, despite the fact that I should have 40 gallons in there.

Jonah · Jul 19, 2016

Also, I wonder if anyone knows where I can access some diagrams for a 1996 208? I don't know how to access the various things that folks like seasick are recommending that I check.

... scratch that! I called GW and they are emailing me some diagrams for the tank, etc. Hopefully I can address this without removing the entire 'lid' from the cockpit.

Michigan Brian · Jul 21, 2016

I have a 1994 208 and there is an access port right in the middle of the deck floor to get at the sending unit

Just pop it off with a screwdriver, its right there.

I had issues with my sending unit and got tired of it so now I just use the fuel flow meter on my Lowrance to monitor fuel levels.

As a sanity check, I have popped the port and removed the sending unit to check to see if the fuel level correlates to what my Lowrance is reporting and its been real close. I also top off and see if that correlates as well

Of course I have to remember to tell it how much gas I put in.

On your stalling I would check for a collapsed fuel line, the inner lining can come apart and it looks fine from the outside, also there is that anti siphon valve that is located where the line connects to the tank. You should be able to get to these through the same access port, its been a while so I don't remember but you don't have to take the big floor hatch out unless you are replacing the tank.

Jonah · Jul 28, 2016

UPDATE:

After being away for about 10 days, I returned to the boat today. Turned the key, and she started right up. :huh I let her idle for a few minutes, then increase the RPMs a bit in neutral. While running, I pumped the primer bulb and noticed that it didn't feel 'tight' or 'full'. It felt like gas was flowing through with air in there too—sort of 'gurgling' through the bulb. After 0.5 gallons, the motor sputtered and died. Would not start back up, and the primer bulb felt empty.

I then removed the sending unit, and manually checked the tank. Indeed, approximately half a tank in there (like my FloScan said). Unfortunately the pickup tube is welded to the tank, and so I couldn't remove it to check for cracks. Instead, I tried raising the front of the boat (using my lift) so that the gas would rise in the back, near the pickup tube. I thought this might trick the motor into thinking there was more gas in the tank, or that it might raise the level of gas past any potential cracks in the tube, but still the primer bulb didn't respond, and the motor wouldn't start.

I then added 10 gallons of gas, and still she wouldn't start. Also tried priming again, but to no avail. Bulb still felt empty.

I then decided to check the water/fuel separator filter. It was only half-full of gas. I topped it off, replaced it, and then after a few minutes of priming (bulb still felt empty) and turning the key, it finally fired up. Ran fine at idle, and at low RPMs, for 0.7 gallons, at which point I had to leave. During that time, while running, the bulb felt empty when I squeezed it. So either I don't know what a primer bulb should feel like (quite possible), or somehow it still isn't filling up at all. After I turned the motor off, I tried priming again, and still it felt completely empty to me.

So, why did it fire up for 0.5 gallons after leaving it for 10 days, and why, after that, did I find the water/gas filter to be only half full of gas? Any why did it start running only after refilling the filter, and why the primer bulb feel half-full the first time it ran, and then feel empty ever since?

I haven't tried taking it out on the water to open it up and see how it performed with this extra fuel in the tank, but will do that over the weekend.

Thanks for any advice!

seasick · Jul 29, 2016

It still seems to be a fuel flow issue. When the motor dies with 1/2 tank or less, disconnect the fuel line from between the primer bulb and the motor and see if you are able to pump (using the bulb) any gas into a can. If so, plug the hose and pump again. The bulb should get firm. If not you have to trace back.
To eliminate almost everything in bewteen, connect a bulb with a piece of hose directly to the fitting on the tank pickup. See if you can pump gas. If it looks good, there is an issue somewhere between the tank and the feed to the primer. It is possible that you have an air leak somewhere. To check that, disconnect the fuel line at the tank and plug it. Pump the primer bulk. It should go soft and collapse due to the vacuum.
You may or may not be able to blow air back into the tank using the short piece of fuel line. It depends on how well the anti-siphon valve is sealing but if you can, you can tell if the gas is bubbling or not by having someone listen at the filler hole. If they hear bubbling the air is coming out below the level of the gas. If all they hear is you blowing than the air is coming out above the fuel level and that would indicate a bad pickup tube (assuming that there is at least 2 inches of fuel in the tank

How did you tell that the water separator filter was half empty? If it is, it means that fuel is not flowing from the tank(bulb should collapse) OR there is an air leak(bulb will remain soft and not collapse).These test assume that the primer bulb is working correctly.

Oh one more thing

Good luck

Jonah · Jul 30, 2016

seasick said:
How did you tell that the water separator filter was half empty? If it is, it means that fuel is not flowing from the tank(bulb should collapse) OR there is an air leak(bulb will remain soft and not collapse).These test assume that the primer bulb is working correctly.

Thanks Seasick. To see that the water separator filter was half empty, I just unscrewed the filter. Is that a sufficient test?

As for your other advice, I'll have to wait until I get back down to about a half tank to run those tests, but I'll do it and report back later.

But in other news, I did make some progress today. I separated the fuel line leading to the motor from the primer bulb, and I tested to see if I could prime gas into a can. At first, I had no luck, and was convinced that the bulb must be bad. I could hear (and feel) air coming back into the bulb from the 'exit' side (side leading to the motor) every time I released the bulb. There seemed to be no stop-valve on the exit side (or else I was clearly broken). But then I read online that holding these bulbs vertically helps the one-way stop valves to fall into position. When I did that, the bulb worked and I could pump gas out of the tank. And when the bulb was nice and full, I let it sit there a while to make sure the gas level didn't drop any lower than the edge of the exit hole, and it didn't.

Does this mean my bulb is bad, or does this just mean I've learned the hard way that these bulbs are meant to be operated in the vertical position?

Either way, I'm encouraged to think that I probably don't have a cracked pickup tube, and that I don't seem to have an air leak between the primer bulb and the tank. But as for why the problem would arise in the first place, maybe it's just that if my primer bulb's one-way valves aren't working properly, it's too hard for my motor to pump fuel up from a half-tank without something to help work against gravity? Would that make sense, or does this mean that both my primer bulb and my fuel lift need to be replaced?

seasick · Jul 30, 2016

Jonah said:
seasick said:

How did you tell that the water separator filter was half empty? If it is, it means that fuel is not flowing from the tank(bulb should collapse) OR there is an air leak(bulb will remain soft and not collapse).These test assume that the primer bulb is working correctly.

Click to expand...

Thanks Seasick. To see that the water separator filter was half empty, I just unscrewed the filter. Is that a sufficient test?

As for your other advice, I'll have to wait until I get back down to about a half tank to run those tests, but I'll do it and report back later.

But in other news, I did make some progress today. I separated the fuel line leading to the motor from the primer bulb, and I tested to see if I could prime gas into a can. At first, I had no luck, and was convinced that the bulb must be bad. I could hear (and feel) air coming back into the bulb from the 'exit' side (side leading to the motor) every time I released the bulb. There seemed to be no stop-valve on the exit side (or else I was clearly broken). But then I read online that holding these bulbs vertically helps the one-way stop valves to fall into position. When I did that, the bulb worked and I could pump gas out of the tank. And when the bulb was nice and full, I let it sit there a while to make sure the gas level didn't drop any lower than the edge of the exit hole, and it didn't.

Does this mean my bulb is bad, or does this just mean I've learned the hard way that these bulbs are meant to be operated in the vertical position?

Either way, I'm encouraged to think that I probably don't have a cracked pickup tube, and that I don't seem to have an air leak between the primer bulb and the tank. But as for why the problem would arise in the first place, maybe it's just that if my primer bulb's one-way valves aren't working properly, it's too hard for my motor to pump fuel up from a half-tank without something to help work against gravity? Would that make sense, or does this mean that both my primer bulb and my fuel lift need to be replaced?

I am one of those who feel that the primer bulb should work vertically or horizontally. The fact that the primer bulb got firm is a good sign as you noted as long as the fuel level in the tank is lower then when you start to experience the problem.
The fact that the filter (separator) was half full doesn't help the diagnosis. It says the the fuel is not being drawn form the tank for whatever reason. The more common cause is an air leak in the separator but other things can cause the same condition. Run with the fill cap unscrewed just to eliminate a vent blockage but I don't think that is the problem. Ti check the lift pump, you will need to measure the fuel supply pressure or just bite the bullet and replace the pump. At this point, there isn't a lot more I can offer.
The filter being half empty means there is an air leak or a blocked vent. You said you changed the fuel lines. Is that correct? A collapsed line will cause starvation but I would expect that an any tank level and not a specific level like less that half full.
It's a puzzler.

cool change · Jul 31, 2016

hi are you priming ur bulb before start up.. even though ur motor will start without priming my mechcanic told me always prime first , because if u dont u will create air pockets in the lines.. Now i dont know if that is true or not but maybe someone could confirm that

seasick · Aug 1, 2016

cool change said:
hi are you priming ur bulb before start up.. even though ur motor will start without priming my mechcanic told me always prime first , because if u dont u will create air pockets in the lines.. Now i dont know if that is true or not but maybe someone could confirm that

In my case, for normal operation, I never prime the bulb, there is no need. The only time I prime is after I have emptied/replaced either my fuel filter(s) or in my case drained my high pressure pump for storage.
There is an odd benefit to not priming: Should something start to go bad, like a weak fuel pump,a leaking filter, clogged filter etc, starting will be harder and that can serve as a maintenance minder.

One caveat to not priming though. Some motors maintain prime (fuel system stays full of fuel) and some may drain down either by design or failure of a component. If your motor does not maintain prime, I would suggest using the bulb.

Confusion: Fuel Tank and Fuel Pump on Adventure 208

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