Odor from Diesel saturated plastic fuel tank

[StephenK]

My bet is that your fuel lines are permeated. Years back, I had the same issue and that was the culprit. Its amazing that permeated lines can cause such an odor. After installing new (properly rated) lines and the problem went away. Another possibility is a loose hose clamp and a slight drip at that point. I'd check both.

[Terry Forshier]

Last year I also smelled diesel. I checked everywhere and found that the fill hose where it attached to the tank was not tight. Overfilling left diesel in the hose and that leaked seeping out of the  tube down on to the tank, then to the underbelly of the boat and into the bilge. Fixing that I thought I had found sloved my problem.
However, I still had some smell and later found some diesel in the bilge. I checked and replaced fuel lines and put diapers (paper kind) all over the bottom of the boat to see if I could locate the area of spillage). I found that I was leaking down the engine. I replaced fuel lines there and also the line from the racor to the engine. Still not it. I then took paper towels and wrapped them around the fuel line connections all over the engine. then with the cover off started the engine and ran it to see if I could find the leak by checking for fuel on the paper towels. After some time i found that one injector was bubbeling when running. (looking from the top) So I ordered new seats (washers) and a new injector. When I removed the injector I found a very small washer that goes on the end of the injector was off and lodged sideways in the hole. It appears that was leaking up through there and down the motor.
As a side, I had intended to order the little fuel lines that go between the injectors from the Universal dealer but upon seeing the price decided to shop around. I went to the local "yard", where I know the mechanics and they pointed me to an alternative fuel line option that was about 1/1000 the price. I just watch the fuel lines more closely now. I learned a lot in this deal and now have a better understanding of whole process of fuel delivery.
Anyhow, just another story and maybe it will help you. Sometimes these problems are just little mess ups that produce big symptoms.

[Ted Pounds]

It doesn't take much of a leak to let the odor out.  You could have a very small pin-hole leak from corrosion in the bottom and not notice any fuel anywhere.  I would recommend pumping out the tank and taking it it out for a thorough inspection.  Also a good opportunity to clean it if that hasn't be done in a while (or ever).  Also an opportunity to make sure you don't have a screen over your fuel pick-up.  

[Ron Hill]

dodger : Now that you know you have a metal tank, start at the tank and check all of those fuel connections.  Then follow the fuel and return lines to make sure there isn't a chaffed thru spot.  Then check all of the hose clamps.

I believe that your nose is going to be your best indicator.  Where you get the diesel smell the strongest is the place to examine in GREATER detail.  A few thoughts

[dodgercc27]

Thanks for all the imput everyone...all very good points and comments.  I will explore further and when I find the culprit I will advise.

Cheers!