Is fuel filter cap likely source of water getting into fuel?

[ctaylor]

Still having symptoms of water in the fuel after tank was drained and filled with fresh fuel in my 2020 GTX 230. Both fuel filters were replaced.
1. A few days after the fuel was drained and replaced jet ski ran great all day long out on the water. HOWEVER, it did idle rough at first and required restarting a couple of times before it got out onto open water and could be opened up full throttle. The ski ran great, top end 65 mph.
2. I replenished the used up fuel with high octane fuel or whatever the most expensive gasoline is these days, about half a tank.
3. About a month after that I started the ski up and it idled smoothly for about half a minute then it began missing badly and would stop running requiring multiple restarts. After about 5 minutes of that bad idling it ran (idled) OK.
4. I repeated this procedure after a couple of times about a month apart each time it had the same result idling smooth for half a minute and then idling rough requiring restarts for about 5 or 10 minutes before it ran idled smooth again.

My theory, and I'd like some comment on it, is that it sets for days and accumulates water from the humidity hear on the coast with its up and down temperatures. The water collects on the bottom of tank which doesn't get picked up by the fuel pump until about half minute later. After 5 to 10 minutes the water in the bottom of the tank is cleared and it idles fine.

Does this sound like water in the fuel? How is water (condensate) getting in there from just sitting outside. (50 feet from the bay). Isn't the fuel system supposed to be sealed up to prevent humid air from condensing into the fuel? BTW, Tthe fuel tank is nearly impossible to get to on this model of SeaDoo.

 

[mkov608]

I live in Pensacola, so no stranger to high humidity. How are you storing the ski? I store mine with full fuel tanks and have never had an issue with water entering the fuel system. Both skis are under Sea-Doo covers, but they are stored outside exposed to the rain. Two skis are 2017 GTR 230 and a 2023 GTR 230.

When the ski runs rough; pull the fuel line from the rail and take a sample. See if there is water in the fuel.

 

[skiasylum]

From small airplane experience we have fuel drains that are checked and drained before the first flight of the day and the fuel tanks were always stored filled, condensation is then not possible with a full tank. Water in the tank was serious and its either from condensation in the tank itself, water egress from a bad cap, or from contamination from another tank from fueling. With the drains we knew the tanks were water free if they were checked.
When you drained your tank the first time could you have left some water in the bottom of the tank?
Have you used any fuel additives like iso-heet to dissolve in any residual water?
In airplanes water in the engines caused mainly detonation and backfiring.
I like mk’s idea of pulling the the fuel line as you could check for water anytime after it has sat for awhile and allowed the water to settle to the bottom.
Also,
When opening a Sea-Doo fuel tank cap, you should expect to feel a noticeable amount of pressure, typically around 5-10 psi (pounds per square inch) due to the fuel tank's design to maintain vapor control and reduce emissions; this is considered normal and is a sign that the fuel cap seal is functioning properly.

 

[ctaylor]

I live in Pensacola, so no stranger to high humidity. How are you storing the ski? I store mine with full fuel tanks and have never had an issue with water entering the fuel system. Both skis are under Sea-Doo covers, but they are stored outside exposed to the rain. Two skis are 2017 GTR 230 and a 2023 GTR 230.

When the ski runs rough; pull the fuel line from the rail and take a sample. See if there is water in the fuel.

Thank you mkov608, Tank is full, is stored outside, not covered now. But the first time I had this problem it was covered. Now the ski is not exposed to the rain. I've had a jet ski since the 90's stored outside and never had this problem. The pressure relief that was mentioned is noticeably not there it always was before, however it has not been hot outside. The question is does it have to be like 90 degrees out side and in the sun for there to be a pressure build up?

Aw Heck!! I meant the title to be fuel FILLER cap. so another question is anything special about the fuel filler cap other than just a cap and a gasket? I've replaced the gasket but there does not seem to be any difference in the old and new.

 

[ctaylor]

From small airplane experience we have fuel drains that are checked and drained before the first flight of the day and the fuel tanks were always stored filled, condensation is then not possible with a full tank. Water in the tank was serious and its either from condensation in the tank itself, water egress from a bad cap, or from contamination from another tank from fueling. With the drains we knew the tanks were water free if they were checked.
When you drained your tank the first time could you have left some water in the bottom of the tank?
Have you used any fuel additives like iso-heet to dissolve in any residual water?
In airplanes water in the engines caused mainly detonation and backfiring.
I like mk’s idea of pulling the the fuel line as you could check for water anytime after it has sat for awhile and allowed the water to settle to the bottom.
Also,
When opening a Sea-Doo fuel tank cap, you should expect to feel a noticeable amount of pressure, typically around 5-10 psi (pounds per square inch) due to the fuel tank's design to maintain vapor control and reduce emissions; this is considered normal and is a sign that the fuel cap seal is functioning properly.

Aw Heck, I meant title to say fuel FILLER cap not filter. I have used STABIL to remove water especially now knowing its likely to have condensate into the tank. my question on that is does the fuel stabilizer act instantly upon addition to the tank or does it have to get mixed up shaken around. I seem to remember something about the fuel pump pressures up the fuel line when the engine is started? See also my reply comments to mkov608.

From small airplane experience we have fuel drains that are checked and drained before the first flight of the day and the fuel tanks were always stored filled, condensation is then not possible with a full tank. Water in the tank was serious and its either from condensation in the tank itself, water egress from a bad cap, or from contamination from another tank from fueling. With the drains we knew the tanks were water free if they were checked.
When you drained your tank the first time could you have left some water in the bottom of the tank?
Have you used any fuel additives like iso-heet to dissolve in any residual water?
In airplanes water in the engines caused mainly detonation and backfiring.
I like mk’s idea of pulling the the fuel line as you could check for water anytime after it has sat for awhile and allowed the water to settle to the bottom.
Also,
When opening a Sea-Doo fuel tank cap, you should expect to feel a noticeable amount of pressure, typically around 5-10 psi (pounds per square inch) due to the fuel tank's design to maintain vapor control and reduce emissions; this is considered normal and is a sign that the fuel cap seal is functioning properly.

 

[skiasylum]

“Stabil" focuses on long-term fuel preservation, while "Iso-Heet" focuses on preventing fuel system issues related to water content.
I think everyone knew from the start you meant “filler” not “filter” no biggie we’ve had a lot better ones that that.

 

[mkov608]

Thank you mkov608, Tank is full, is stored outside, not covered now. But the first time I had this problem it was covered. Now the ski is not exposed to the rain. I've had a jet ski since the 90's stored outside and never had this problem. The pressure relief that was mentioned is noticeably not there it always was before, however it has not been hot outside. The question is does it have to be like 90 degrees out side and in the sun for there to be a pressure build up?

Aw Heck!! I meant the title to be fuel FILLER cap. so another question is anything special about the fuel filler cap other than just a cap and a gasket? I've replaced the gasket but there does not seem to be any difference in the old and new.

Pressure relief when you remove the fuel cap is normal in higher ambient temperatures when thermal expansion inside the tank caused the pressure increase. When I remove my caps when it's cold, there is no air pressure escaping from the tank.

I worked on jets for 28 years in the AF, and though the aircraft had drains, we never took fuel samples during pre-flight checks. A little water in a F100-PW-220 didn't hurt anything. F-16 fuel drains were so bad, they would stick open and you couldn't get them to close; must have been built by the lowest bidder.

 

[skiasylum]

Key points about positive fuel pressure in a Sea-Doo:

• Purpose:
  The positive pressure helps to capture fuel vapors that would otherwise escape into the atmosphere, complying with emission standards.
  
  
• Pressure range:
  Depending on the Sea-Doo model, the typical fuel tank pressure can range between 5-10 PSI.
  
  • Fuel tank pressure sensor: Monitors the pressure within the fuel tank and sends data to the engine control module (ECM).
    
    
  • Fuel cap seal: Plays a crucial role in maintaining the positive pressure by preventing vapor leaks.
    

 

[skiasylum]

 

[mkov608]

Key points about positive fuel pressure in a Sea-Doo:

• Purpose:
  The positive pressure helps to capture fuel vapors that would otherwise escape into the atmosphere, complying with emission standards.
  
  
• Pressure range:
  Depending on the Sea-Doo model, the typical fuel tank pressure can range between 5-10 PSI.
  • Fuel tank pressure sensor: Monitors the pressure within the fuel tank and sends data to the engine control module (ECM).
    
    
  • Fuel cap seal: Plays a crucial role in maintaining the positive pressure by preventing vapor leaks.

Curious, what's creating the positive pressure? Fuel tanks pressure sensor? Where is that on the schematic? I don't recall seeing one.

Oh! Love the pic of the F100! Reminds me of the days of jumping F-16 inlets to perform engine inspections. Always hated going in there after they sucked up a bird ... oh the smell....

 

[skiasylum]

A Sea-Doo jet ski maintains positive pressure in its fuel tank by using a sealed system with a fuel tank vent that is designed to allow air to enter the tank only when necessary, preventing excessive fuel vapor release while still allowing fuel to flow out as needed, effectively creating a slightly pressurized environment within the tank.

Key points about this system:

• Fuel tank vent:
  The vent is not simply an open hole; it has a mechanism that regulates the pressure inside the tank, opening only when pressure drops below a certain level to allow air to enter and replenish the pressure.
• Vapor recovery system:
  Some Sea-Doo models may include additional components like a vapor recovery system that captures fuel vapors and returns them to the tank, further contributing to pressure management.
  • Reduced emissions: By preventing excessive fuel vapors from escaping, positive pressure helps to reduce hydrocarbon emissions into the atmosphere.
  • Improved fuel efficiency: Maintaining a slight positive pressure ensures consistent fuel delivery to the engine, promoting better fuel economy.
    

 

[mkov608]

Interesting. I've read a lot of Sea-Doo manuals, and I've never come across that bit of info. Is this from a Sea-Doo boat manual? Notice is says "some Sea-Doo models" for vapor recovery (like a car). So in this case under "Fuel Tank Vent" it allows air in as fuel is used. Pressure in the tank will be atmospheric; since it only states it "lets air in" there won't be any pressure in the tank besides atmospheric unless there is thermal expansion due to heat.

 

[skiasylum]

Apparently warmer return fuel from the engine causes a constant buildup of pressure inside any fuel tank that uses a return line system because the return fuel is heating up the colder fuel in the tank and causing expansion which causes a constant positive pressure which then can be regulated. Positive pressure to a certain extent in a fuel tank is a good thing.

 

[mkov608]

But all Sea-Doo PWCs use a return-less system ... single supply line from the pump to the fuel rail. I can't image the fuel rail getting that hot; the factory fuel rails are plastic.

 

[skiasylum]

Most fuel injected Sea-Doos utilize a fuel return line as part of their fuel injection system, allowing excess fuel to be sent back to the fuel tank, regulating pressure and ensuring proper operation.
Key points about fuel return lines in Sea-Doos:
Function:
The return line helps maintain consistent fuel pressure by sending excess fuel back to the tank, preventing over-pressurization.
Modern systems:
While some newer Sea-Doos might use a "returnless" fuel injection system, which doesn't require a dedicated return line, most older and mid-range models still have a return line.

2000-2003 Sea-Doo Jetski OEM Gas Fuel Feeding and Return Hoses Set GTX DI RX | eBay

 

[Milehighguy303]

Just another opinion to consider… I don’t think your issue is water in the fuel and you have successfully eliminated that as a possibility. The reason I would suggest this is there really isn’t a logical explanation for how significant amounts of water would keep getting in the tank. Even with minor condensation, this is a small fraction of water in the fuel that would be contaminated and likely not enough to cause drivability issues. And others would be experiencing similar symptoms and that doesn’t seem to be the case. And there isn’t a logical explanation for lake water to be splashing in the area, not draining like it is designed to do, and water going in the tank when you open the fuel cap.

If I were you, I would turn my attention to the throttle body, Idle air control valve, mass air flow sensor, or other fuel related controls. I think you previously said you replaced the spark plugs, but make sure you have correct original equipment plugs first. Maybe even replacing them again for good measure. If fresh plugs don’t change performance, then start considering fuel related controls.