Engine Dies around 1/2 tank of gas - Help Needed

Here is my issue - Full tank of gas (1991 Ski Nautique 400 hrs) runs like a champ. When the gas gets to around 1/2 tank all of a sudden it will begins to sputter and then quit. It has happened 4 times now and always when the gas is used down to around 1/2 tank.

Here is what I have done so far as troubleshooting -

Replaced accelerator pump on carb (Probably not related but it needed it anyway)

Replaced water separating fuel filter (Did this after the first time it happened because when I bought the boat a month ago that was with it (Brand new)) Was worth a shot.

Checked anti siphon valve on tank - Good

Attempted to check fuel feeding tube on tank but it won't come of the tank. It just spins like the thread unit in the tank is not holding. Pulled the tank and took out sending unit and visually inspected the feeding tube (as best I could) and it looked okay.

Basic fuel pump test by removing the coil wire and turning the key over. 8 turnovers netted 12 oz of gas.

My neighbor mentioned that it could still be the fuel pump and with a full tank of gas there is enough (head pressure?) where the pump doesn't have to work that hard to supply the fuel? - Any thoughts on that?

Finally is there a way to (Pressure test?) the fuel pump to see if it is not up to par under load?

I know there is a wealth of knowledge on here so I thought I would post before I sent it to a mechanic for diagno$stic testing. $$$

Thanks in advance.

Gary

Thanks GottaSki. Appreciate the advice. I have tried and failed several times to get to the dip tube. I will keep trying. My assumption was some type of fracture or hole in the tube. Thoughts?

Thanks hdspringer99. I am planning on tackling it again today.

Did you confirm that the line doesn't have any pin holes or anything like that?

Maybe you can add a fuel pressure gauge and see if pressure is dropping when the sputtering begins.

Update - Took the boat out and it did the same thing again around the half way mark. I took a 2 gallon can of gas on the boat for when this happened. I took the fuel line from the fuel filter and stuck it straight in the gas can. Gas Can -> Fuel pump nothing in between. It ran perfect. Tells me pump is fine.

The problem seems to be between the tank and the pump. As I see it there are two things between the two. Fuel Filter and Fuel Line. The fuel filter is 2 weeks old.

The guys at SkiDim pointed to the fuel line possibly being degraded or otherwise "worn out" from Ethanol or just 24 years of age.

Could the fuel line possibly be collapsing somewhere in route to the pump once the fuel reaches a level where gravity is no longer helping?

Might want to check the overflow vent at the same time, some kind od bug may have mad a nest in there

Replacing the main line wouldn't be a bad idea to start with.

Can the dip tube fit inside a 5 gallon gas can? The only one I found here on CCF included a return line for fuel injection.

It would be nice if you could run the boat off a fresh line from the filter to the tube inside a gas can, then slowly pick up the tube out of the gas. If it runs OK then sure seems like its the fuel line. If it doesn't, repeat bypassing the filter.

UPDATE - Still need help
I changed the fuel line and took the boat out with less than 1/2 tank of gas... It rine great for an hour or so, then it just died same as before. I read on some other posts folks saying coil overheating issues, but that is past my knowledge.. It doesn't look like I have a normal distributor cap (again way past my knowledge) so I am posting pics of what I have. Any and all help is appreciated. You guys have been great so far. I will post pics soon

https://www.dropbox.com/s/jg4sqr35q48z922/IMG_3391.JPG?dl=0

https://www.dropbox.com/s/xjachlc90sc8tuq/IMG_3395.JPG?dl=0

https://www.dropbox.com/s/uws6msrq5g8ewew/IMG_3396.JPG?dl=0

Try again with the photos. Go to the FAQ in the maintenance forum for assistance.

How do you know the anti-siphon is OK?

KRoundy - Checked it and it was okay, but replaced it and the pick up tube to be on the safe side. Replaced fuel line too.

Bri8g2001 - I did just that today. Between 1/2 and 1/4 tank cold. Ran awesome for about an hour and a half then quit.

Bri892001 wrote: Are you starting your voyages with a full tank every time? In other words, have you ever set out with the motor being cold, and only half a tank?

91NaughtyQ wrote: Bri8g2001 - I did just that today. Between 1/2 and 1/4 tank cold. Ran awesome for about an hour and a half then quit.

Now that it doesn't seem to be fuel tank related, Kevin sure nailed the best potential issue below!

Hollywood wrote: ProTec! Oh no. You don't have "a" coil. You have 4 and they all suck. Get a timing light. You've most likely had ignition issue all along.

Gary,
With a failing Protec, you have one choice and that's convert to a distributor. There's a couple links to great threads on the process in the FAQ thread. Do confirm the problem as Kevin suggests with the timing light. The "4" comment and not an "a", is referring to 4 times the problem. IE: 4 coils in a system notorious for failure versus 1 standard coil.

Your Pro Tec system is most likely failing. Time to go get a DUI.

This is in the FAQ, but here's a direct link for you: DUI Installation Instructions

Everyone--

thanks for the info and all of the tips and advice. I will be replacing the Pro Tec with either a DUI or standard set up. I am going to check on both options and price/benefit ratio. You guys are awesome!! If anyone is in NC and could help that would be awesome. I think setting Timing is a bit out of my league considering the importance of it being right.