2000’s Explorer 250 fuel tank questions

[DoratheExplorer]

Hey everybody, first post here. I’ve been reading all day here. Lots of good info but a few things I can’t find answers to. I’m in the market for a 250 Explorer. It’s come time to upgrade from my 89 Mako 210 Walkaround since the family has grown. I love my boat but in my research, I’ve found a lot of late model explorer 245/250s for sale in my price range and they seem to fit what I’m looking for (maximum deck space, small cabin for storage and small child potty emergencies, shelter being the console, full transom, trailers BLE ect…)

Anyway, I went to look at a 2001 250 and immediately found issues with the fuel tank. Issues I’m confident are serious, but they raised more questions about the general construction of the late model explorers without the coffin hatch access. I should state that I have installed a new fuel tank in my mako after buying it and realizing the tank has failed and drained gas, not only into the coffin, but into the foam expansion holes below and into the hull… it wasn’t fun and I don’t intend on doing it again.

So I immediately smelled gas coming from the rear inspection plate, the cabin and rear bilge. I dipped a rod into the coffin near the rear of the tank and got about an inch of fuel. Now I know that pretty much means a tank failure since I didn’t see evidence of the sender or the full/vent hoses leaking. But my question is if the coffin area is isolated from the foam construction of the boat or if the fuel just went down and soaked everything? Also, I read that it is normal for water to pass through, under the tank between the front and rear bilges. Is that true? When I’m shopping around to buy, what amount of water down there is concerning? I noticed the inspection plate o rings were almost completely disintegrated and had probably been leaking for years. Is there generally enough ventilation down there to make it okay to have those leaking?

[Capt. Bob]

So I immediately smelled gas coming from the rear inspection plate, the cabin and rear bilge. I dipped a rod into the coffin near the rear of the tank and got about an inch of fuel. Now I know that pretty much means a tank failure since I didn’t see evidence of the sender or the full/vent hoses leaking. But my question is if the coffin area is isolated from the foam construction of the boat or if the fuel just went down and soaked everything? Also, I read that it is normal for water to pass through, under the tank between the front and rear bilges. Is that true? When I’m shopping around to buy, what amount of water down there is concerning? I noticed the inspection plate o rings were almost completely disintegrated and had probably been leaking for years. Is there generally enough ventilation down there to make it okay to have those leaking?

So, a lot going on here.

First, here's a great shot of how they were put together.
https://classicaquasport.com/gallery/showphoto.php?photo=11993&title=00catpg3&cat=749

In the 90(s) model Aquas, water did pass from bow to stern through the tank compartment. The tank itself rested on a platform above the centerline (keel). which allowed water to pass under the tank.

Here is that construction style.
https://classicaquasport.com/gallery/showphoto.php?photo=5729&title=1995-catalog-pg02&cat=628

I'm not certain that happens on the 2000 models since it has a dropped in stringer shell (as shown in the first photo). I don't recall seeing a tank replacement on a 2000 era hull so I don't know for sure. Still any water that has made its way into the compartment and has not escaped can and will lead to tank corrosion. What you have indicated in your post seems to confirm this. Therefore, I myself would probably let this one pass and continue the search.

Good luck.

[msteinkampf]

Hello Dora,

245 Explorers were built with aluminum fuel tanks and were designed to be able to allow water to move from the anterior bilge through the fuel compartment and on to the bilge in the stern. This is a good news/bad news situation: The bad news is that because of this design and the way the manufacturer installed the tanks (with rubber strips under and around the tank), water could collect in the tank and cause corrosion. The good news is that because of this design, water or fuel that leaks into the fuel compartment is contained by the stringers lateral to the tanks, protecting the foam between the stringers and the hull. Really, in a 20-year-old boat with an aluminum fuel tank, you should expect that it will need to be replaced soon. In this case, you know it needs to come out, so if you like the boat otherwise, I would suggest you subtract the cost of cutting open the deck and replacing the tank (and all the hoses) from the asking price. As someone who has spent a fair amount of time in an Explorer fuel tank compartment recently (see here: https://classicaquasport.com/smf/index.php?topic=16118.0), I think this is a doable project. And really, the seller is going to have a tough time selling this boat, so someone who isn't intimidated by a fuel tank replacement could get a real bargain on an Explorer.

M

[msteinkampf]

Actually, the fuel tank compartment design allows water to collect around the fuel tank, causing corrosion at the points of contact between the tank and the rubber strips. Corrosion can also occur within the tank from the effect of water that collects beneath the gasoline in the bottom of the tank (and my fuel tank had both types of corrosion).