How to confirm source of fuel leak?

[SBH2OMan]

Well, I'm afraid I have the dreaded fuel smell and gas in the bilge after recently filling the tank past the 1/2 way point.

I've checked the hose connections of the filler and vent hoses and both look fine. I also checked the gasket on the sending unit and it is also fine.

The boat has a 148 gallon tank (according to Parker).

The boat is slipped, and normally we keep it with about 50-75 gallons, because the scuppers and lower unit sit underwater to begin with and any more fuel makes it sit very low.

I added 40 gallons for an island trip on Saturday and after fueling the cabin smelled REALLY badly of raw gas (the filler hose is accessible from under the galley counter, behind the fridge (which is currently removed).

Checking the aft bilge (while underway), I stuck my hand down into the water and could definitely detect fuel in the water.

We made the (I know, dangerous) call to continue on and use up the extra gas, since there is no practical way to remove it otherwise. After returning and sitting in the slip for about 3 hours, the raw gas smell had subsided.

There's definitely a leak somewhere that is happening when the tank is filled more than 1/2 full, whether or not we are underway.

What is the best method to determine where the leak is coming from? I want to be darned sure its a fuel tank problem before I spend $5,000+ to rip up the back deck and replace the tank...

Has anyone used tracer dyes for this sort of thing? (I know they are common for finding AC leaks in cars and commercial HVAC systems).

Thanks

 

[Brent]

Pull pie plates over fuel sender and fuel fill and vent hoses on tank. Any smell?

I have Racor fuel and water filter with bottom clear bowl and drain and regularly check for water.

m2cw is the top and top of sidewalls are failing

I assume pressure checking the tank might help if you have some one with experience. I would be concerned with a cowboy blowing it out

or having it scoped through fuel fill and tank sender port by someone good

sorry but have the same boat and understand

I just serviced the fuel sender and add new screws and fuel resistant sealant, so far no problems or water

 

[Brent]

I was looking for tank scoping firm in SW Florida but at 25 yrs ago, Why? Time to pull and upgrade the tank and do it better. epoxy coating, thicker AL, foam sealed on top, WEMA Sender, better bonding attachment points instead of posts, ask about increasing vent port size. I dont know if I need dual pickups but why not. Since I run a RACOR filter and will be changing it to dual filters ( 10 micron then 2 micron filter) both with bowls, I plan to install fuel pickuptube as deep as possible like one inch from bottom to maximized fuel capacity. If that makes sense

If I cant a find a local guy, it is going to Warthog.

 

[Brent]

Do you have a seam around the perimeter of cockpit deck?

I do. I wondered if it is screwed down and just need to sand off gelcoat to find the heads?

 

[SBH2OMan]

Do you have a seam around the perimeter of cockpit deck?

I do. I wondered if it is screwed down and just need to sand off gelcoat to find the heads?

Yes, there’s an obvious seam all around the perimeter of the deck. Makes for a good guide to cut, I suppose.

I’ve been running a clear bottom fuel filter for about 6 years now and never seen any water in there.

I’m still hoping that the problem might be something other than a perforated tank...

One thing I’m thinking about is whether it might be cool to install two smaller tanks. That way when I’m carrying 75 gallons it can all be more forward instead of sloshing around the entire cockpit area. I also like the idea of two tanks and being able to switch over. (Must be from my old days as a motorcyclist)...


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[mheltunen]

Do you have a seam around the perimeter of cockpit deck?

I do. I wondered if it is screwed down and just need to sand off gelcoat to find the heads?

I’ve wondered what the purpose of that seam is as well. That would be great if somehow the deck was easily removable


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[mheltunen]

Based on the data and symptoms you provided I suspect the tank is Leaking.Here’s the deck and tank drawings that I have for mine :

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[SBH2OMan]

Based on the data and symptoms you provided I suspect the tank is Leaking.Here’s the deck and tank drawings that I have for mine

Thanks. Do you happen to have those as PDF files? (If so can you PM them to me?)

Come to think of it, that would be a great idea - a files section here on the forums for various plans. I know I’ve collected a few over the years.

I really want to be able to confirm the issue before I cut open the deck. Lousy timing - just as the season is starting!


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[Brent]

Try stud finder on the deck. mark some spots and remove gel coat around a few of them to start
I somewhat thought ring shank nails were used but could be mistaken

 

[SBH2OMan]

Based on the data and symptoms you provided I suspect the tank is Leaking.Here’s the deck and tank drawings that I have for mine :

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Hey Mark, FYI I talked to Eric Denton (engineer at Parker) and he told me that your stringer drawing is not accurate for my boat (which I assume is the same as yours under the deck) so be careful about trusting that DVSC drawing. According to him, my tank is farther back than indicated in your drawing.

 

[mheltunen]

Based on the data and symptoms you provided I suspect the tank is Leaking.Here’s the deck and tank drawings that I have for mine :

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Hey Mark, FYI I talked to Eric Denton (engineer at Parker) and he told me that your stringer drawing is not accurate for my boat (which I assume is the same as yours under the deck) so be careful about trusting that DVSC drawing. According to him, my tank is farther back than indicated in your drawing.

Good to know. If you have the correct drawing please send it to me. My vessel is a 1994 2320 extended cabin


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[SBH2OMan]

Good to know. If you have the correct drawing please send it to me. My vessel is a 1994 2320 extended cabin

Unfortunately he told me that they had a computer crash a couple years ago and lost a lot of old drawings, so he didn't have it.

 

[mheltunen]

Well that’s unfortunate.


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