Replacing 1997 22' cruiser fuel tanks

J

james gill

New member
My mechanic (I am not mechanical) says ethanol is dissolving my old tanks and is the reason filters are clogging with gunk. No C-Dory dealer around here, any advice on what replacement tanks to get, and installation tips specific to C-Dory 22'? Should I make the 14 hour drive to Wefings in Florida to make sure its done right (maybe water in core under tank hold-down screws?)

Thanks,
James
 
Just curious: Do you have the opaque 18-gallon Moeller tanks (held down by little clips)? I didn't know ethanol would dissolve those - thought it was only fiberglass tanks that did that. Not that I would put anything past ethanol :amgry If not the tanks, maybe the hoses?

I replaced my original translucent plastic tanks (25 gallon) with the "current" Moeller 23-gallon tanks used in the 22 Cruiser (at least they were in 2012). Since our generation 22's don't have the slightly raised liner in the fuel tank area that came in around 2007 with the flat cockpit sole, you end up with a few inches of space above the tanks (between the top of the tanks and the bottom of the splashwell). I used that to good advantage mounting the trim tab HPU there on starboard side (and there is room left over for other things as well).

These tanks are licensed (or whatever the correct term is) to be made and sold by Moeller, so you can technically buy them from C-Dory or from any Moeller dealer. I happened to be in Washington at the time, so I bought them from C-Dory (when they were in Ferndale). As I remember it they were around $250 for the pair.

These tanks also sit just inside of the forward lip of the splashwell molding, so you have the option of running the solid/fiberglass tank fronts (the type you typically see on later models with the little windows for viewing fuel level). (The tanks are translucent enough to see the fuel level inside them so no need for sending units.) I bought and cut matching fiberglass to add those panels, but in the interim ran with a pair of Sunbrella type "curtains" and decided I like the functionality so much I may not go to the solid boards (you do want to keep UV off the tanks and fuel, so some type of cover is good).

I would definitely want to seal any core holes. There are a variety of ways to go back with fuel tank hold downs that don't compromise the core. Examples would be holes into the core that are overdrilled and filled, then fastened into; cleats fibergassed to the upper skin of the sole (bottom), or etc. I fastened fiberglass angles (purchased pre-made at McMaster-Carr) to the sole skin and then attached my tanks to those via straps.

Here is the data on the tanks:

Port:
Moeller_Marine_FT2340_port_tank.jpg

Starboard:
Moeller_Marine_FT2339_stbd_tank.jpg

A note is that I'm not sure which tanks you are starting with. I had the 25-gallon Waylander tanks, and I was able to re-use the fuel fills in their stock position. That's something to check if you have the 18-gallon Moeller tanks (may be fine, just not something I've looked at). I replaced all the hoses at the same time (plus overdrilled/filled around the fillers, etc.) and I did go to a "Michelin tire man" type filler hose on the port side, to help make the bend around the lazarette well and put less stress on the filler neck of the tank. That type of hose is more flexible than regular type.

(Actually, if I were to do it again I would instead make a "tunnel" of sorts through the lazarette well so that the hose did not have to make that dog-leg. Reason is that dog leg makes one have to fill slower on that side, and I would not miss that small amount of space taken from the port lazarette.)
 
Edit: I see Sunbeam has already posted her information on the tanks..While I was having lunch..

The replacement of fuel tanks is a fairly easy project. A number of us can talk you thru it. Moeller makes a take which is 23 gallons, and is made in the port and Starboard side configurations. I have the Moeller, which is 25 gallon (measured buy fill up). The 23 gallon was developed because of the floor which is in the most recent boats. I have the removable floor, which does not affect the tanks.

The best advice about core penetration is to pull the tanks, and then test the core, by drilling out the screws which hold the batten or straps in place. If it is wet, when you drill out--then further investigation is necessary. If there is moisture, as indicated by a moisture meter, then you may want to do some test holes, (which can be easily filled with thickened epoxy) to determine the extent of the damage (don't drill thru the bottom of the boat!)

If the boat is kept out of the water, and covered--not subject to free, thaw, with water in the bilge etc--it is unlikely that there is significant core degeneration.

When you put in the new tanks, you should glass in new battens to hold the tanks in place, and any screws should go into these battens, instead of the hull.

Now as to if ethanol and gas are destroying your tanks:
Coast Guard did a two year long test on plastic fuel tanks and found that gasoline alone and gasoline with alcohol had no measurable affect on plastic tanks.
Click to expand...

Gasoline is a blend of multiple hydrocarbons. For the most part polyethylene is very resistant to these chemicals, as it is to ethanol, (and other alcohols).
Certainly fiberglass tanks are attacked by gasoline and ethanol. There is little evidence that this occurs in plastic tanks (Polyethylene in this case).

I would pull the tanks, completely empty them, and then clean them. If there is sign of deterioration, then certainly replace. If not deteriorated, then you can put them back in, with the new battens and straps.

Sunbeam has both posts and information in her photo album which show excellent information on replacement.

As for cleaning. I have used hot water, soap, with pebbles in the tanks, sealed them, and then tumbled for some time. I have also used a medium pressure--pressure washer. Some steam clean, but too much heat can damage the tank. I do regularly "polish" the fuel--at the beginning of a season--this involves a fuel pump, 10 micron Racor filter, and some tubing--takes about an hour for each tank to recirculate the fuel and pretty much remove any material from the fuel which is in the tank. .

Also, when were your fuel lines replaced? They can be a source of the problem.
 
Ethanol may be your problem, but unless you have fiberglass tanks, I doubt it is dissolving your tanks.

I have the original plastic tanks that I removed from my 22 and I use them for occasional long term storage of ethanol and they have suffered no ill effects from this use or the previous use with ethanol fuel while in the boat. They would still be in service in the boat but were replaced to gain more fuel volume.

More than likely your problem is:

Bad fuel
Accumulated debris in the fuel system or fuel tank
Deterioration of fuel, vent or fill lines.

My guess is accumulated debris in the fuel tanks, perhaps a result of previous bad fuel or old fuel. I have used the remove the tanks and shake them up with pebbles in them procedure that Dr. Bob described to loosen and then flush out the debris and gunk and it works.

Mark at Wefings is a great guy but Florida is a long way and removing and cleaning and flushing tanks as well as coring screw holes are fairly simple procedures that any shop should be able to handle. That said, bringing the boat to him for repairs and hitting the Florida gathering at the same time is a great idea.

Best of luck
 
What material was used to build the tanks? How old are the fuel hoses? They can fail, too. When replacing them from tank to OB along with fill and vent hoses. Are you using an external fuel tank filter like a RACOR? What does the gunk look like? I would replace the fuel pickup tubes if keeping the tanks.

My mechanic (I am not mechanical) says ethanol is dissolving my old tanks and is the reason filters are clogging with gunk.

What is vague to me? Any specifics? If could be accumulation at the tank bottom since fuel pickup tubes do not reach the tank bottom. fuel pickup tubes and hoses breaking. I would be sure and avoid the time and money for new tanks. Any fuel leakage or odors?
 
Thanks, all. Sounds like bad tanks is not so likely even tho 20 yrs old, but bad gas and possibly hoses. So I will try to empty, clean, replace hoses and check that result. Yes, there is some leakage at filling, I guess gaskets at the top of the tanks need replacing. If I can ever retire, I may need the larger tanks for some major water treks, but I only get occasional weekends now.
Thanks again.
 
Unless you have fuel gauges there probably are no gaskets at the top of the tank. But the fuel fill and vent hoses are probably original and should be replaced; that is likely a point of leakage, where they are double hose clamped onto the inlet of the fuel fill and the outlet of the tank vent. As almost all of us suggested, the lines from the tanks to the selector valve, and from the selector valve to the engine should also be replaced.

When you have the tanks out--then you can look at the battens which hold the that in place and core.

Actually replacing the tank is not much more work than taking the tanks you have out, and cleaning them--plus replacing all of the fuel lines.
 
If they were like the originals on my 94 (18 gallon grey things), they have a fuel gauge and gasket and that is where my leak was. Sadly, I ended up changing out the tanks because of severe corrosion between the screws and bedded nuts in the top of the tank that secures the fuel float. They leaked pretty bad and when I took them apart it was clear not much was clamping the gauge float to the top of the tank. I suppose that could be fixed - I probably should have tried since there was nothing else wrong with them at all. The 19 gallon Moeller tanks amazon sells for about $200 bucks are almost a direct replacement and are equal quality.
 
My tanks '97 are somewhat translucent polyethylene but very hard to see fuel level (unless dark outside and a flashlight shining into tank). They do have fuel gauge (do not work well despite replacement a few years ago)
with gasket on top, which is where the fuel is leaking. Are you suggesting it may be just as well to replace tanks instead of cleaning, and replacing gaskets?
 
Perhaps. The tanks have a boss fitted for nuts in the mold and this houses the bolts that secure the fuel gauge assembly into the tank. Mine were disintegrating and even eating into the plastic mold. I tried to make one tank work as it wasn't too bad, but it still leaked when full and I wouldn't run it that way.

A tank repair shop might be able to fix this, but I didn't even try as the new ones were not expensive and the repair shop is $150 an hour. BTW, it sounds like we have/had the same tanks. I hope you are able to seal yours - I didn't really want to spend the $400 bucks on new tanks, but went that route as mine seemed like a lost cause.
 
Polyethylene tanks (at least the tops--I would not consider fooling with any damage to the bottom of the tank because of risks), can be polyethylene welded. There are also some ways that some epoxies can be used to rebuild the area where the fuel tank sensor enters the tank, and the flange is bolted down. These can be from replacing the nuts, to putting in new threaded half backing plates thru the existing holes. These then solve the nut problem. Of course you should be sure that all fuel is out of the tanks, and that they have been thoroughly cleaned and no fuel fumes remain before any work on the area where the sensor bolted in. I have also have very good luck with Permatex Form a gasket compounds.
 
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