Grady Fuel Tank Help

[NightOwl15]

Hello Grady Experts, looking for some insights please on following:

My Boat: 2001 Grady Sportsman 180, center console, hard-top, Yamaha 2-stroke 130HP, 350+ hours.

My Problem: During commissioning this year, noted fuel sender head on top of tank, just under deck porthole aft center console, was pretty corroded. Yard suggested we replace, but warned “it can open a can of worms.” Still, corrosion seemed excessive, so went for it…..well it opened a can of worms alright. 1 of screws was stripped, seal around sender was decomposed to a mushy mess, fuel tank opening into which sender goes is so warped and misshapen that getting old sender out proved problematic. Drained tank and found zero, none, no H2O in tank which was good, and engine, carbs, etc. all checked out clean. Now have been told by 2 yards, w/ excellent services/mechanics that best thing to do is…..replace the fuel tank.
Have asked if can plug old hole and just not having a fuel gauge, re-sealing a new sender, but no options seem to be plausible as tank surface is so uneven a new seal will not be tight and will result in fuel leakage, which is clearly not acceptable. There’s tag on the wire of sender indicating it’s the original sender from `01, so it’s time is up….I guess. Just seems crazy that a $100 part can bring my boat to complete standstill and require major work like tank replace. [Deep breath]

My questions:
1. Anyone heard of this before on grady’s or w/ plastic tanks?
2. No fuel in tank, but corrosion on sender might indicate leaking porthole above it?
3. I’m going to take it to local grady dealer here in Eastern MA, but should I consider another outfit to replace tank? Suggestions for 1?
4. Am I really going to replace the tank on a `01 18’ grady…..Seems hard to believe.
5. Any other ideas….?

Any suggestions would be terrific. Thanks!

 

[NightOwl15]

here are some pictures to spur any discussion, would love suggestions. If in fact I have to replace, which seems to be the vibe I'm getting, then any suggestions for quality shop in Eastern MA in the NE to do this kind of work on a grady??
The pics in reverse order are, sender in tank and general condition of head, remains of seal once sender was lifted up, and condition of sender hole into tank......again the tank surface is warped and uneven now around the hole.....a new seal is seemingly not possible.
Ideas?? Thanks all!!

 

[Rangoonb]

I used Atlantic Coastal Welding out of NJ. It was for an aluminum tank. 175 gal Coast Guard sealed, epoxied and ready to drop in was $1,200. Filled out the online order form with all measurements on Monday and finished tank was shipped Friday. Not cheap but should be a 30 year tank. Those pics of your plastic tank are pretty eye opening....good luck

 

[NightOwl15]

Thanks Rangoonb. plastic is my material of choice here, but appreciate your lead.

 

[Greatty]

Wow, that is an eye-opener, as I too have a '99 180 and periodic inspection has revealed slight pooling of moisture in this location on my tank as well. After owning this boat for 9 years I thought that this poly tank was impenetrable, but now I know that's wrong. Good luck and please keep us posted. - Bob

 

[Sharkbait282]

We have a new-to-us 282 Sailfish that's been in the water for 2 months up here in RI. One of the commissioning tasks that we dealt with was to get the main tank back into "usable" condition, prior owner had disclosed they had watered fuel pumped out and hadn't used the main tank for 24 months or more.

Long story short. Water gets into or onto your tanks in two primary ways. First past the degraded or missing O-rings on the fuel fill caps. Bad/cracked/o-rings? replace them. Missing o-rings? replace them. Replace them often.

The second part is that deck plates aren't meant to be permanently water tight for a long period of time without regular maintenance. That INCLUDES re-bedding the deck plate surround on a regular interval, since it's a piece of hardware we typically stomp all over during the boating season, eventually breaking the seal the silicone or caulk between the deck and deck plate surround and mounting screws.

When we opened up our deck plates to pull out the last of the cheese/fuel/water mix from the main tank, the deck plates all but fell off once the screws were removed. As a long time sailboat owner, where hardware is under load and subject to side forces regularly, this wasn't surprising, but it's still concerning since water can easily get onto your fuel tanks once that silicone seal is compromised.

Maybe every 2-3 years, remove the screws, pull on the deck plate. Well bonded? put the screws back in with a little fresh goo in the screw holes. If the deck plate seems to pull up at all, take it off entirely, clean both surfaces to the best of your ability with a straight razor and solvent, and re-bed the deck plate.

Two cents.

 

[seasick]

The flange of the tank may flatten out when the new sender is screwed on. Assuming the stripped screw can be removed, the next size up screws may fix the stripped issue. Clean the flange and actually see what the deflection (warping) is using a straight edge. You might be able to install a new sender using a combination of one or two gaskets and sealant. You need to buy sealant intended for gasoline applications. NO silicone, 5200, 4200 etc. Screws should be a bit snug but not over tightened. The poly tanks usually last a long time.
The fact that there was no water in the tank means that the sender seal was intact and therefore the new sender may seal OK too. The corrosion is from salt water and salt buildup in the bilge. As mentioned, a deck plate could be leaking but it can just be bilge water in general . Grady recommends flushing the outside of the tank tank with a hose every now and then. Of course keeping the bilge as dry as possible will help (check all those deck plates and gaskets etc.
I would take a shot at reusing the tank. Remember that an empty tank with gas fumes is extremely volatile so be aware of doing anything that might ignite fumes. That includes power tools, vacuums , electrical sparks and the like.
Good luck

 

[onoahimahi]

This looks like a good "challenge..." :hmm

No shop is going to suggest trying to fix your old tank so you will have to try it yourself. They can only do things "by the book" but you as the boat owner can get creative. Why not give it a try before throwing in the towel on your existing tank?

You main concern is the distorted opening but since this is plastic, that could very well straighten out when you tighten up the new metal sending unit. It looks like they chopped the hole in that tank with a chisel so it could have been distorted since new. The last sending unit I replaced was stainless steel and had a thick cork gasket. The stainless steel plate combined with the thick gasket might just do the trick. If should be obvious whether you got a good seal by visual inspection and you would keep an eye on it during your first few trips.

I'd be tempted to first try tightening up the sending unit without the gasket to see how flexible the plastic is and whether or not the distortion is coming out. If it is really not flattening out, there are some other things you could try, like warming up the plastic if you can find a safe way to do it, or using double gaskets, or building up the lip area with a fuel-safe epoxy.

You mentioned that one nut stripped so you will have fix that. Perhaps you could tap it to the next largest size or epoxy in a new nut.

-Scott

 

[NightOwl15]

going w/ new WEMA seals and sender, dealer says tank will snug/pull up to seal as all plastic tanks can "shrink and swell some in heat/cold." If pressure test shows no leakage then good to go. Seals over time will look like above due to reaction w/ ethanol, not uncommon. For now NO new fuel tank needed. We'll see. Thanks to all for the input and thoughts, very, very helpful! The post above about the porthole reseal is indeed worth doing. Am on that next. Thanks all!!