94 150HP XRi stalled once again after fuel tank gets down to about 10 gallons

[h2oHokie]

I posted before about this problem and thought it was stator related because the last time out it seemed to happen only at WOT. This time I couldn't stay running and actually stalled a few times. I got it running again by squeezing the primer bulb, the motor ran great and I went straight to shore. The primer bulb stayed compressed after I squeezed it as if there was a vacuum in the line. The last time I had the problem I had already refilled the fuel tank before I troubleshooted the fuel system and the bulb would regain its shape and get firm after squeezing. Both times out the engine ran great on a full tank for about 14 - 15 gallons. Once the fuel gets down to about 10 gallons the problem reoccurs. This leads me to believe that there may be a tear in the pick-up tube in the fuel tank. This is a fixed internal 25 gallon fuel tank. I'm assuming I can just pull the fuel hose off the tank and remove the plate holding the threaded elbow connector that mounts to the top of the tank, and there should be a pickup tube with a filter. My SELOC manual gives plenty of information related to the engine regarding the fuel system, but doesn't mention much about the fuel tanks. Will I need to bleed the fuel system in case any air was pulled in or does the engine have safeguards in place to keep that from happening. TIA

 

[hkeiner]

Re: 94 150HP XRi stalled once again after fuel tank gets down to about 10 gallon

Re: 94 150HP XRi stalled once again after fuel tank gets down to about 10 gallon

You might consider first connecting a portable fuel tank (e.g., 3-6 gallon size) to the motor to see if the problem goes away (or not) to confirm that your problem is caused by the fuel line coming from the built in tank.

 

[gotmach]

Re: 94 150HP XRi stalled once again after fuel tank gets down to about 10 gallon

Re: 94 150HP XRi stalled once again after fuel tank gets down to about 10 gallon

Try changing your anti-syphon valve first. It could be sticking and is a cheap part.

 

[h2oHokie]

Re: 94 150HP XRi stalled once again after fuel tank gets down to about 10 gallon

Re: 94 150HP XRi stalled once again after fuel tank gets down to about 10 gallon

Why do I even need an anti-syphon valve if my fuel tank is always below the fuel supply line and the powerhead. Can I troubleshoot the valve simply by removing it from the supply line? Here's a picture from the Coast Guard site regarding antisyphon valves

 

[h2oHokie]

Re: 94 150HP XRi stalled once again after fuel tank gets down to about 10 gallon

Re: 94 150HP XRi stalled once again after fuel tank gets down to about 10 gallon

Why do I even need an anti-syphon valve if my fuel tank is always below the fuel supply lines and the powerhead. Can I troubleshoot the valve simply by removing it from the supply line?

 

[studlymandingo]

Re: 94 150HP XRi stalled once again after fuel tank gets down to about 10 gallon

Re: 94 150HP XRi stalled once again after fuel tank gets down to about 10 gallon

Is your tank vent stopped up?

 

[gotmach]

Re: 94 150HP XRi stalled once again after fuel tank gets down to about 10 gallon

Re: 94 150HP XRi stalled once again after fuel tank gets down to about 10 gallon

I'm not saying you have an anti-syphon fitting, but if you do it is something to check. The vent is a good possibilty too. Spiders like clogging up vent holes according to a repair tech I talked to. I am having a similar problem and I'm just passing on the info of things I was told to check.

 

[Silvertip]

Re: 94 150HP XRi stalled once again after fuel tank gets down to about 10 gallon

Re: 94 150HP XRi stalled once again after fuel tank gets down to about 10 gallon

The anti siphon valve prevents fuel run-back from the engine to the tank on an outboard. Although the flapper valves in the primer bulb should also prevent that, they can leak causing drain back. If the primer bulb is being sucked flat, the restriction is between the outlet of the bulb and the tank. A broken pickup tube in the tank will not cause the bulb to suck flat. it would be the same as the engine simply running out of gas because the break is above the fuel level. I doubt the anti siphon valve is the problem since it wouldn't be fuel level sensitive. They either stick or they don't and it doesn't matter how much fuel is in the tank. There may be some crud floating in the tank that blocks the pickup once fuel level reaches a certain point. Check the pickup to at least eliminate that part of the system.

 

[hkeiner]

Re: 94 150HP XRi stalled once again after fuel tank gets down to about 10 gallon

Re: 94 150HP XRi stalled once again after fuel tank gets down to about 10 gallon

Temporarily connecting a portable tank to the motor is a good way to confirm that your problem is fuel tank related before you do a lot of part swapping and other troubleshooting steps needlessly. However, if you prefer to identify as many possible causes of your symptoms, so that you can choose among them as your particular problem to fix, the following table is a good source of information.

 

[h2oHokie]

Re: 94 150HP XRi stalled once again after fuel tank gets down to about 10 gallon

Re: 94 150HP XRi stalled once again after fuel tank gets down to about 10 gallon

Thanks for all of the input. I will follow up with the fix once I have the problem solved. I will also get a small 3 gallon tank before I go out the next time to keep on board. Can't hurt keeping one board in case of emergency. It just seems strange that it could be a crud/buildup problem when there is still that much fuel in the tank. You would think the fuel has to be at a lower level, but maybe this crud has a certain bouyancy that puts it at the right level at 10 gallons. I did add Startron enzyme fuel treatment to the fuel this last time out, but who knows if that helped or hurt the situation.

 

[hkeiner]

Re: 94 150HP XRi stalled once again after fuel tank gets down to about 10 gallon

Re: 94 150HP XRi stalled once again after fuel tank gets down to about 10 gallon

A 3 gallon portable tank is a good investment. I use my 3 gallon portable tank to periodically decarb my engine and to periodically clean my carbs using SeaFoam. I don't keep it on the boat otherwise.

 

[gotmach]

Re: 94 150HP XRi stalled once again after fuel tank gets down to about 10 gallon

Re: 94 150HP XRi stalled once again after fuel tank gets down to about 10 gallon

Update on my problem (similar of yours)

I have a 1990 Starcraft ss160 with an internal bow mounted tank. There is only a small access hole where I could get to the valves. Anyways I pulled off the anti-siphon fitting to find it was replaced with a regular fitting. I then took off the T shut off valve. I then removed the fitting that screwed into the tank and the pick up tube was attached to it. When I pulled it out it was all covered with ton of tar which i am assuming is varnish. I blew thru it and it was slightly restricted but not enough I feel is causing the problem. One thing I did notice when I pulled it out that there is an internal tube inside the tank that guids the pick up hose down into the tank. Is it possible that at the end of that tube is a screen and that screen is all covered with tar? If so with a full tank of gas you would have more pressure to push the gas thru the the screen and with a 1/2 tank there would be less pressure which would keep the fuel from passing thru the screen? I have not been able to find a diagram yet of what the inside of the tank looks like so I am guessing.

I'm going to clean the pick up tube and then try to put some clearer down the tube to see if it will free up some of the crud.

 

[Don S]

Re: 94 150HP XRi stalled once again after fuel tank gets down to about 10 gallon

Re: 94 150HP XRi stalled once again after fuel tank gets down to about 10 gallon

I originally put this together for I/O's, but it works just as well for outboards.

http://www.iboats.com/bbboard/bbBoard.cgi?a=viewthread;fid=24;gtid=1107009

 

[gotmach]

Re: 94 150HP XRi stalled once again after fuel tank gets down to about 10 gallon

Re: 94 150HP XRi stalled once again after fuel tank gets down to about 10 gallon

I siphoned out all my gas and it took awhile....The gas came out at a really slow pace. This makes me believe the pick up screen is all gummed up. I now plan of filling my tank up 1/2 way with Por15 Marine Clean & Water and letting it set for 2 days. I will then siphon out the marine clean/crud and followed that up by hooking up a shop vac to help suck out at much as I can. I havent decided if I want to just let the tank sit for awhile and evaporate out the rest while running on external tanks or If I will put a few gallons of gas in it with some dry gas, mixing it up a bit, then siphon and dispose of the bad gas. In either case I will add an extra fuel filter and check it regularly. I hope this works.

 

[bamadave]

Re: 94 150HP XRi stalled once again after fuel tank gets down to about 10 gallon

Re: 94 150HP XRi stalled once again after fuel tank gets down to about 10 gallon

Why not pull the pickup tube and manually clean it if you think that is the problem. The bulb sucking down and not getting hard could be a stooped up vent. Is the tank built in or a portable tank. If portable, is the vent screw open?

 

[bamadave]

Re: 94 150HP XRi stalled once again after fuel tank gets down to about 10 gallon

Re: 94 150HP XRi stalled once again after fuel tank gets down to about 10 gallon

Why not pull the pickup tube and manually clean it if you think that is the problem. The bulb sucking down and not getting hard could be a stopped up vent. Is the tank built in or a portable tank. If portable, is the vent screw open?

 

[gotmach]

Re: 94 150HP XRi stalled once again after fuel tank gets down to about 10 gallon

Re: 94 150HP XRi stalled once again after fuel tank gets down to about 10 gallon

My tank is built into the bow with very limited access. I have a hole about 7 inches in diameter to reach through and I could bearly reach the valves on the top of the tank. I took off the hose fitting. Then removed a T shut off valve. Then unscrewed a fitting screwed into a big nut on top of the tank. The fitting screwed into the nut had the pick up hose attached to it with a spring inside the hose. At the end of the hose was an open platic cylinder. When I pulled the hose out it felt like there was a metal tube within the tank still that guided the pickup hose down into the tank. I am assuming the pickup screen is part of this tube inside the tank. Can I get to it by taking off the nut on the top of the tank? Or if I remove the nut will it fall inside the tank? I have not had any luck finding a diagram of how the tank is put together so I was thinking about playing it safe.

 

[gotmach]

Re: 94 150HP XRi stalled once again after fuel tank gets down to about 10 gallon

Re: 94 150HP XRi stalled once again after fuel tank gets down to about 10 gallon

H2oHokie I didnt mean to hijack your thread here.....have you had any luck on your end?

 

[h2oHokie]

Re: 94 150HP XRi stalled once again after fuel tank gets down to about 10 gallons

Once again thanks to everyone's replies. I have yet to get my boat out since the last trip where the problems showed up again, but I have been troubleshooting in my driveway. Didn't mean to diappear on everybody; like I said before as soon as I nail this problem I'll post for the results. I have run the motor on dry land without any problems, but this is only at very low rpms. I never provide any assistance by squeezing the primer bulb and the motor never stutters, skips or stalls. The pickup tube for this tank appears to be molded into the tank so there is no way to separate the tube from the tank without breaking it. I'm going out this weekend (fingers crossed) and will have an extra primer bulb and 3 gallon tank with me. One question: with EFI do you really need to have the primer bulb in the line between the tank and the motor or can you run a straight line?

 

[studlymandingo]

Re: 94 150HP XRi stalled once again after fuel tank gets down to about 10 gallons

Yes, you do still need to have the bulb for efi. Takes a while to get fuel to the pump after the boat is sitting for a short while.

One thing I was thinking, you should try opening the filler cap when you have the flat-bulb syndrome. That would very effectively diagnose whether tank venting was the problem.

I recently installed a 55 gallon tank in my boat, I had to swap the fittings (vent and pickup) so the pickup tube would be sternward. The fittings were different so I had to purchase an additional pickup tube; the new tube didn't come with a screen and the instructions recommended not using one.

Several threads here and on other sites suggest not using a screen and only using an inline filter for the express reason of the screens being prone to clogging.​